Melanoma on ultrasound: what does it show, what do metastases look like, and can cancer be ruled out?

A standard ultrasound examination cannot reliably determine whether a mole or pigmented spot is melanoma. If melanoma is suspected based on clinical presentation and dermatoscopy, a definitive diagnosis requires tissue examination. Ultrasound for melanoma has other applications: high-frequency skin examination can preliminarily estimate the tumor depth, and standard ultrasound is particularly useful for regional lymph nodes and superficial metastatic lesions. [1]

Primary melanoma often appears on high-frequency ultrasound as a hypoechoic, solid lesion darker than the surrounding dermis. However, this appearance is nonspecific: other benign and malignant skin tumors can have similar echogenicity. Therefore, the diagnosis of "hypoechoic lesion" does not necessarily mean "melanoma," and a normal ultrasound does not rule it out. [2]

The most proven practical role of ultrasound in established cutaneous melanoma involves regional lymph nodes. A metastatic node may become more rounded, acquire a hypoechoic cortex, lose its normal fatty chyle, have an irregular contour, and exhibit abnormal vascular patterns. However, even a suspicious ultrasound image requires morphological confirmation. [3]

Ultrasound is not a substitute for sentinel lymph node biopsy. The most recent meta-analysis from 2026 showed that preoperative ultrasound detects only about a third of occult regional metastases in patients who are indicated for sentinel node biopsy. Therefore, a negative ultrasound does not necessarily mean that micrometastases are absent. [4]

What do they want to find out with the help of an ultrasound?	What the method can actually do
"Is this a mole or a melanoma?"	Doesn't determine reliably
Thickness of the suspicious skin lesion	Can be preliminarily assessed using high-frequency ultrasound
Precise Breslow	Determined histologically, not by ultrasound
Metastases in the superficial lymph nodes	One of the main areas of application
Micrometastasis in a normal sentinel node	May miss
Subcutaneous/in-transit metastases	Can visualize superficial lesions well
Metastases throughout the body	Ultrasound does not replace computed tomography, positron emission tomography, or MRI.
Melanoma of the eye	Special situation: ophthalmological ultrasound has a much more important diagnostic role

A source on the current role of ultrasound in the diagnosis and monitoring of melanoma. [5]

Can primary melanoma be detected on ultrasound?

Yes, some primary melanomas can be visualized with high-frequency ultrasound, but seeing a lesion and diagnosing a melanoma are not the same thing. Skin examination uses transducers with a significantly higher frequency than conventional abdominal ultrasound: the higher frequency improves the resolution of superficial structures while simultaneously reducing the depth of ultrasound penetration. [6]

On a typical ultrasound image, melanoma may appear as a relatively uniform hypoechoic area in the dermis. In some tumors, color Doppler imaging reveals internal or peripheral blood flow. However, neither hypoechogenicity nor vascularization are specific features of melanoma: similar characteristics are also found in other skin neoplasms. [7]

This is precisely what limits ultrasound as a primary diagnostic method. A Cochrane review of high-frequency ultrasound studies found that combinations of certain sonographic features could demonstrate high sensitivity in individual studies, but specificity varied widely, and the quality of evidence was insufficient to support the use of ultrasound as a substitute for standard clinical diagnostics. [8]

The primary diagnostic approach remains the same: a suspicious lesion is first assessed clinically and dermatologically, and then, if suspicion persists, tissue is obtained. The current European interdisciplinary consensus clearly states that if melanoma is suspected, histopathological examination is necessary. [9]

High-frequency ultrasound is more useful as a preoperative adjunct. It can show how deep a mass visible on ultrasound is, whether it extends into the dermis and subcutaneous tissue, and where its inferior border lies. This can aid in surgical planning, especially for thicker tumors. [10]

Therefore, the phrase "hypoechoic skin lesion" in the protocol alone does not allow the lesion to be labeled a melanoma. Similarly, the absence of a clearly visible tumor mass on a standard ultrasound does not allow the statement "melanoma excluded." [11]

Ultrasound sign of the primary lesion	How to interpret it
Hypoechogenicity	Possible in melanoma, but nonspecific
Relatively homogeneous structure	May occur
Clear lower boundary	Helps to measure depth
Uneven/increased blood flow	May increase concern but does not confirm the diagnosis.
Size of the hearth	It can be measured
Thickness on ultrasound	Preliminary assessment
Histological type	Not detectable by ultrasound
Melanoma in situ or invasive tumor	It is finally determined by morphology

A source on modern high-frequency ultrasound capabilities in dermatology. [12]

What does melanoma look like on high-frequency ultrasound?

There is no single ultrasound image that can be used to say "it's definitely melanoma." A hypoechoic solid structure is most often described, but echogenicity, shape, and vascularity vary depending on the tumor thickness, subtype, and surrounding inflammatory response. [13]

In one study, early melanomas were more likely to have a flat, oval, or spindle-shaped shape and relatively well-defined margins, while more advanced tumors became more rounded and could have less distinct borders. The authors specifically emphasized the limited value of this method for differential diagnosis. [14]

Doppler imaging can detect vascular signals within or around a tumor. More pronounced vascularization may accompany biologically active tumor processes, but blood flow also exists in many benign lesions, inflammatory lesions, and other skin cancers. Therefore, Doppler imaging is not a "malignancy test." [15]

Melanoma may also be too thin to be reliably measured with the available equipment. This is especially true for melanoma in situ and very thin T1 tumors, where a difference of a few tenths of a millimeter is clinically significant, and the technical error becomes comparable to the thickness of the lesion itself. [16]

Another problem is that ultrasound does not measure tumor cells directly, but rather the boundaries of an area with different acoustic properties. Inflammatory lymphocytic infiltrate, residual nevus, and differences between living tissue and fixed histological specimens can lead to discrepancies between ultrasound and pathological thickness. [17]

Therefore, in a clinical report, it is more accurate to write about the ultrasound thickness or depth of the lesion, rather than the "Breslow ultrasound index." The Breslow index is a pathological measurement of invasive melanoma after tissue examination. [18]

Can ultrasound determine the thickness of a melanoma using the Breslow method?

Ultrasound can be a good preliminary estimate of the thickness of some melanomas, but does not replace the histological Breslow measurement. The most convincing current data are obtained for high-frequency transducers and thicker tumors. [19]

A meta-analysis published in the Journal of the European Academy of Dermatology and Venereology in 2025 included 36 studies. The correlation between high-frequency ultrasound thickness and histology was high in most studies; the median correlation coefficient was 0.94. [20]

Accuracy was significantly dependent on transducer frequency. For frequencies of 10-20 MHz, the average correlation with histology was lower than for 20-25 MHz, and the strongest correlation was observed in studies with frequencies of 70 MHz and higher. Such ultra-high-frequency devices, however, are not standard equipment in every ultrasound room. [21]

The method also worked better for melanomas thicker than approximately 0.75 millimeters. Very thin lesions are more difficult to separate from normal epidermis, inflammation, and technical artifacts. [22]

Sometimes, ultrasound evaluation is more accurate than histological evaluation. Researchers cite the surrounding inflammatory infiltrate, the presence of a nevus component, and tissue shrinkage during fixation and processing of the pathological specimen as possible explanations. [23]

The practical value of preliminary measurements lies in surgical planning. For example, if the tumor appears sufficiently thick, it is easier for the physician to plan surgical treatment in advance and decide whether regional staging should be considered simultaneously. However, the final T-category is assigned only after histology. [24]

Method	What is measured	Status
High-frequency ultrasound	Estimated lesion depth/thickness in vivo	Additional method
Histology	Breslow thickness of invasive melanoma	Standard
Dermatoscopy	Surface architecture and structures	Diagnostic tool
Confocal microscopy	Cell-like structures of the superficial layers	Additional method
An ordinary photograph	Type and dynamics of education	Breslow does not measure

Source of meta-analysis of high-frequency ultrasound accuracy.[25]

What does an ultrasound of the lymph nodes show in melanoma?

Ultrasound examination of regional lymph nodes is one of the most important clinical applications of ultrasound in melanoma. It allows for the detection of structural changes in the superficial cervical, axillary, inguinal, and other accessible lymphatic basins before some nodes become apparent upon palpation. [26]

A normal lymph node typically has an oval or bean-shaped form, a relatively thin cortex, and a persistent echogenic fatty chyle. In metastatic melanoma, the architecture may gradually deteriorate.[27]

A recent 2026 study specifically comparing cervical lymph nodes with melanoma metastases and benign nodes showed more frequent irregular borders, hypoechoic cortex, occult or absent chyle, abnormal vascular pattern, and posterior acoustic enhancement in metastatic nodes.[28]

Shape also matters: as tumor replaces the lymph node, it often becomes more rounded. However, size or roundness alone is not sufficient—a reactive node can also enlarge and change shape after infection or inflammation. [29]

Doppler ultrasonography evaluates the vascular pattern. A benign reactive nodule often retains a central hilar blood supply, whereas a metastatic process may be accompanied by peripheral, mixed, or disorganized vascularization. However, this sign also lacks absolute specificity. [30]

If a doctor sees a suspicious lymph node, the next step may be ultrasound-guided fine-needle aspiration or core biopsy. In this case, ultrasound is used for guidance, and the final answer comes from cytological or histological examination of the tissue obtained. [31]

Ultrasound sign of a lymph node	Possible interpretation
Oval shape, preserved chyle	Most often a benign picture
Rounding	Increases alertness
Localized thickening of the cortex	May be an early warning sign
Hypoechoic cortex	More common in metastases
Disappearance of fatty chyle	A suspicious sign
Uneven outline	Increases the likelihood of tumor damage
Peripheral/disorganized blood flow	A suspicious sign
Several signs at once	Much more important than one sign

Source on modern signs of melanoma metastases in the cervical lymph nodes. [32]

Can a normal lymph node ultrasound rule out metastases?

No. A normal ultrasound image significantly reduces the likelihood of a large metastatic lesion, but does not exclude microscopic metastasis. This is the fundamental limitation of ultrasound in the initial staging of clinically negative lymph nodes. [33]

A micrometastasis may be a very small cluster of cells within a sentinel node that has not yet changed its shape, cortical thickness, chyle, or blood flow enough to be visible to an ultrasound transducer. Therefore, a morphologically positive sentinel node often appears completely normal on ultrasound. [34]

Older studies had already shown this problem, but in 2026 it was confirmed by a new systematic review and meta-analysis of 19 studies with 7396 patients. The pooled sensitivity of preoperative ultrasound was only 33.6%, while the specificity was 92.4%. [35]

In other words, if we take 100 patients with true occult sentinel node disease, a typical preoperative ultrasound strategy may miss a significant proportion of them. Therefore, a negative report such as "no abnormal regional lymph nodes were detected" does not equate to a negative sentinel node biopsy. [36]

A positive ultrasound has practical value. If a suspicious nodule can be confirmed by fine-needle aspiration before surgery, the patient is already considered to have clinically detectable regional disease, and the subsequent treatment algorithm is modified. [37]

Thus, the main rule of interpretation is that ultrasound is good at searching for structurally visible metastases, but is not sensitive enough for the smallest micrometastases. [38]

Can ultrasound replace sentinel lymph node biopsy?

No. In a patient whose primary melanoma characteristics indicate a sentinel lymph node biopsy, a negative ultrasound does not automatically preclude this procedure.[39]

Sentinel lymph node biopsy is fundamentally different from ultrasound. It first identifies the true primary lymphatic drainage pathway using lymphatic mapping, then the removed node is examined microscopically. This allows for the detection of tumor deposits that do not yet cause ultrasound changes. [40]

Traditional targeted high-resolution ultrasound studies have shown a sensitivity of approximately 20-30% for occult sentinel node lesions. It is precisely small metastatic deposits that most often remain invisible. [41]

A new meta-analysis from 2026 did not reverse this conclusion. Its authors, however, suggested a more modern application: ultrasound plus targeted puncture of a suspicious node may identify a proportion of patients with already large regional lesions before SLNB, which is potentially important in the era of neoadjuvant immunotherapy. [42]

That is, the role of ultrasound is expanding, but it is not becoming a substitute for morphology. More accurately, ultrasound can detect a node that should be punctured; a negative ultrasound does not exclude the need for SLNB if it is indicated by the stage and Breslow. [43]

Situation	Ultrasound	Sentinel node biopsy
Large suspicious node	Very useful	Usually no longer the main task
Micrometastasis	May miss	It is intended specifically for its detection.
Shows the actual first lymph node	Not always	Yes, after lymphatic mapping
Receives fabric	Only with puncture	Yes
A negative result excludes micrometastasis.	No	Much more reliable
Can be used for follow-up	Yes	No, this is a one-time surgical procedure.

Source on limitations of preoperative ultrasound before SLNB. [44]

At what stages of melanoma is an ultrasound of the lymph nodes performed?

International recommendations are not formulated entirely uniformly, so it is impossible to provide a single, universal rule for all countries and centers. The most detailed European diagnostic consensus of 2025 recommends ultrasound examination of regional lymph nodes starting from stage IB. [45]

The same European consensus states that for very thin melanomas up to 0.8 millimeters thick, additional imaging is not required. Beginning with stage IIB-IIC, systemic examination is expanded to include computed tomography or positron emission tomography, along with magnetic resonance imaging of the brain. [46]

A separate 2025 ESMO guideline is somewhat more broad in its definition of imaging, recommending that in stages IIB and above, ultrasound, computed tomography and/or positron emission tomography (PET) scans should be considered along with brain magnetic resonance imaging (MRI) for a complete assessment of prevalence.[47]

The American College of Radiology also does not consider ultrasound to be a universal whole-body screening tool in its 2026 updated criteria. Its role depends on the clinical situation: it may be appropriate in cases of suspected regional disease, recurrence, and in certain surveillance scenarios. [48]

Thus, the difference in recommendations concerns mainly the intensity of low- and intermediate-risk imaging, rather than the basic principle: the higher the risk of regional recurrence, the greater the practical value of ultrasound monitoring of the accessible lymphatic basin. [49]

Therefore, it is more useful for the patient to focus not on the formula “everyone with melanoma should have an ultrasound every six months,” but on their own stage, sentinel node status, and the chosen monitoring program. [50]

Stage/situation	Typical role of ultrasound
Melanoma in situ	Regional ultrasound is usually not required.
Very thin pT1a	Routine imaging is not usually necessary.
Stage IB	European consensus recommends LN-US
Higher regional risk	The importance of ultrasound is increasing
IIB-IIC and above	Ultrasound is already being supplemented by systemic visualization
Positive sentinel node without complete dissection	Ultrasound can be used to monitor the pool
Suspicious node at any stage	Targeted ultrasound + morphological examination

Source of the European Recommendation 2025, DOI 10.1016/j.ejca.2024.115152. [51]

How is ultrasound used after a positive sentinel lymph node?

Following a microscopically positive sentinel node biopsy, regular ultrasound surveillance of the regional lymph node basin has become an important alternative to automatic removal of all remaining lymph nodes. This strategy emerged from studies demonstrating the feasibility of safe active surveillance in appropriately selected patients. [52]

With this approach, the examiner sequentially measures and compares the lymph nodes in the corresponding basin, paying attention to the cortex, chyle, shape, and blood flow. If a new suspicious lesion arises, a targeted puncture or biopsy is performed. [53]

A 2024 systematic review and meta-analysis of 36 studies with over 18,000 patients estimated the pooled sensitivity of ultrasound surveillance to be approximately 88% and the specificity to be approximately 97%. These figures relate to surveillance for regional recurrence, not to the search for microscopic disease before primary SLNB.[54]

This distinction is crucial. Ultrasound is a poor substitute for SLNB at the micrometastasis stage, but is much more effective in the subsequent detection of a growing metastatic node that has already begun to change its structure. [55]

The role of ultrasound continues to evolve, however, due to the widespread use of modern computed tomography and positron emission tomography. In a 2026 study of 240 patients with a positive sentinel node, cross-sectional imaging detected the majority of reported recurrences, while ultrasound detected only a small proportion and prompted more negative biopsies than true positives.[56]

The authors of this study therefore raised the question of whether, in the era of modern systemic imaging, it is necessary to maintain historical protocols for frequent ultrasound examinations for each patient so strictly. This does not mean the abandonment of the method; rather, it reflects a shift toward individualized monitoring. [57]

What do subcutaneous and in-transit metastases look like on ultrasound?

Ultrasound is particularly useful for superficial metastases in the skin and subcutaneous tissue, as these lesions are located close to the transducer. These include satellite, in-transit, and some cutaneous or subcutaneous metastases. [58]

In-transit metastases occur along the lymphatic pathways between the primary melanoma site and the regional lymphatic basin. Clinically, they may present as small, firm nodules in or under the skin. [59]

On ultrasound, such lesions often appear as well-defined hypoechoic nodules in the dermis or subcutaneous tissue. Doppler imaging may reveal significant blood flow within them, even at relatively small sizes. [60]

However, a hypoechoic subcutaneous nodule may also be a cyst, an inflammatory lesion, a lipoma with an atypical appearance, another cancer, or a benign neoplasm. Therefore, in an oncological context, a suspicious new nodule usually requires morphological verification. [61]

Ultrasound navigation is particularly useful if the nodule is small, deeply located in the subcutaneous tissue, or difficult to palpate. Image guidance can be used to perform fine-needle aspiration, core biopsy, or to mark the lesion before surgical removal. [62]

In cases of multiple superficial lesions, ultrasound helps map locoregional disease but does not answer the question of whether metastases coexist in the lungs, liver, brain, or bones. This requires stage-oriented systemic imaging. [63]

Surface find	Possible ultrasound image
In-transit metastasis	Hypoechoic dermal/subcutaneous nodule
Subcutaneous metastasis	A clearly defined, solid structure
Small metastasis	It may be better seen by ultrasound than by palpation.
Doppler	Often demonstrates internal/peripheral blood flow
An unclear knot	Can be punctured under ultrasound navigation

Source on interventional ultrasound in patients with melanoma. [64]

Will an ultrasound show melanoma metastases in the liver and other organs?

A routine abdominal ultrasound can detect some fairly large liver metastases, but a normal examination does not rule out systemic metastatic disease. For complete staging of high-risk cutaneous melanoma, methods capable of evaluating significantly more organs and smaller lesions are used. [65]

When liver metastases are involved, they may have varying echogenicity and do not have a single, specific ultrasound appearance. Small lesions are particularly easy to miss, while obesity, liver steatosis, deep location, and body type further limit the sensitivity of the examination. [66]

Current European guidelines for cutaneous melanoma do not recommend routine abdominal ultrasound as a substitute for systemic staging of stages IIB and higher. For high-risk melanoma, computed tomography or positron emission tomography (PET) is used in combination with magnetic resonance imaging (MRI) of the brain. [67]

Magnetic resonance imaging is particularly useful for detailed liver examination when CT scans reveal an indeterminate lesion or there is a high clinical suspicion of small metastases. In modern oncology imaging, MRI has a high sensitivity for small liver metastases. [68]

Therefore, the result “liver without focal changes on ultrasound” is a good finding, but in a patient with high-risk or metastatic melanoma it does not cancel out the studies that are provided for by the stage. [69]

Conversely, a lesion discovered incidentally on liver ultrasound in a patient with melanoma should not automatically be labeled a metastasis. Cysts, hemangiomas, focal fatty lesions, and other benign lesions are common and require proper characterization. [70]

How does ultrasound differ from PET-CT, CT, and MRI for melanoma?

Ultrasound works best where the object is superficial and can be examined precisely; computed tomography, positron emission tomography, and magnetic resonance imaging solve systemic problems. These methods are not interchangeable. [71]

Ultrasound is convenient for lymph nodes, skin and subcutaneous tissue: it does not use ionizing radiation, can be repeated many times and allows the needle to be immediately directed to a suspicious area. [72]

CT scans evaluate the chest, abdomen, and pelvis and are therefore better suited for looking for widespread disease in internal organs.[73]

Positron emission tomography combined with computed tomography visualizes metabolically active lesions throughout the body and is particularly useful in more widespread melanoma, although small regional micrometastases may also be below its resolution.[74]

Magnetic resonance imaging is the most important method for the brain and is of high value for the liver, bone and many soft tissue locations. [75]

This is why modern staging melanoma is multimodal: the doctor does not need “the best scan in general” – he needs a method that is optimal for a specific issue. [76]

Method	Strong point	The main limitation
High-frequency ultrasound of the skin	Thickness and surface extent	Does not confirm histological diagnosis
Ultrasound of the lymph nodes	Superficial regional nodes	Misses some micrometastases
Ultrasound + puncture	Quick morphological check of an accessible node	Only accessible fires
CT	Lungs, chest/abdomen/pelvis organs	Ionizing radiation
PET-CT	Systemic metabolic map of the disease	Small foci and the brain have limitations
MRI of the brain	The best specialized method for brain metastases	It is not a universal examination of the whole body

Source on modern multimodality imaging in melanoma. [77]

Ultrasound or PET-CT for lymph nodes: which is better?

For small, superficial regional lymph nodes, high-quality ultrasound is often very sensitive to structural changes, while PET-CT is better at determining the extent of disease throughout the body. Therefore, comparing them as direct competitors is not entirely appropriate. [78]

A historical meta-analysis of diagnostic imaging demonstrated the very high accuracy of ultrasound in monitoring regional lymph nodes and the superiority of PET-CT in searching for distant metastases. Although technology has improved significantly since then, this functional principle remains valid. [79]

PET-CT may miss a microscopic deposit within a normal-sized lymph node simply due to spatial resolution. For the same reason, PET-CT, like ultrasound, does not replace sentinel node biopsy at the appropriate stage. [80]

Ultrasound, on the other hand, allows for a very detailed examination of the cortex and chyle of a superficial node and immediate puncture. However, it will not simultaneously show all the lungs, bones, and deep organs. [81]

Therefore, for high-risk melanoma, the doctor may use both methods for different purposes, rather than choosing one of them permanently. [82]

What does a "hypoechoic lymph node" mean in melanoma?

Hypoechogenicity of a lymph node is not a diagnosis of metastasis. This term only describes the fact that the tissue reflects less ultrasound and appears darker; reactive and inflammatory lymph nodes can also be hypoechoic. [83]

The physician analyzes not only the overall echogenicity but also the distribution of changes. For example, focal or asymmetric cortical thickening may be more suspicious than uniform reactive hyperplasia. [84]

Preserved echogenic chyle is often a reassuring sign, while its disappearance or replacement by tumor tissue increases the suspicion of metastasis. But even here, there are exceptions. [85]

The vascular pattern is also important. Disorganization or peripheral blood supply combined with disruption of the nodule's architecture is significantly more suspicious than a single hypoechoic area. [86]

If the pattern of features is truly alarming, it is usually more appropriate to obtain tissue under ultrasound guidance than to try to “prove metastasis” with additional measurements of the same node.[87]

What does an "enlarged lymph node" mean in melanoma?

An enlarged lymph node in a person with melanoma requires evaluation, but enlargement is not always caused by metastasis. Skin infections, vaccinations, inflammation, recent surgery, and other conditions can cause reactive lymphadenopathy. [88]

Size is therefore only one parameter. A small nodule with prominent focal cortical pathology may be more suspicious than a large oval nodule with preserved chyle after infection.[89]

If a node is palpable or appears suspicious, ultrasound helps identify the most abnormal area and decide on a puncture. This differs clinically from the situation where all nodes are normal and SLNB is used to search for hidden micrometastases. [90]

If regional metastasis is confirmed, the patient no longer requires just a repeat ultrasound, but a full assessment of the stage and discussion of further treatment. [91]

Is it necessary to have regular ultrasounds after melanoma removal?

Not all patients and not on the same schedule. Modern surveillance should be individualized based on stage, risk of recurrence, sentinel node biopsy result, and treatment received. [92]

The European Diagnostic Consensus recommends a stage-based program and includes lymph node sonography starting at stage IB. However, the authors explicitly note that the optimal intensity of surveillance requires further study. [93]

A review of international guidelines showed significant differences, with some guidelines routinely recommending lymph node ultrasound, while others use it primarily in higher risk, no SLNB, or surveillance after a positive sentinel node without complete lymph node dissection.[94]

A recent ASCO 2026 review emphasizes that intensive imaging alone does not always improve survival and may increase the number of false-positive findings and additional procedures. [95]

Therefore, self-mandating "ultrasound of all lymph nodes every three months" after a thin, low-risk melanoma makes no sense. The schedule should be tailored to the specific stage and the current monitoring protocol. [96]

If a new enlarged node, subcutaneous formation or local symptom appears outside the planned schedule, a separate indication for a targeted examination arises. [97]

How has the role of ultrasound in melanoma changed in recent years?

The main change is not the emergence of a completely new ultrasound method, but a more precise understanding of where ultrasound is truly useful and where its capabilities are limited.[98]

First, a 2025 meta-analysis of high-frequency ultrasound confirmed the high correlation between ultrasound assessment of primary melanoma depth and histology, especially at higher frequencies and in thicker tumors. This strengthens the role of HFUS in preoperative planning but does not make it a diagnostic substitute for biopsy. [99]

Secondly, a 2026 systematic review found that preoperative ultrasound of lymph nodes before SLNB has a sensitivity of only about one-third. Thus, current data once again refute the idea that a good ultrasound machine can simply replace surgical sentinel node examination. [100]

But the same work suggested a new potential role: if ultrasound reveals a suspicious node and puncture confirms metastasis, the patient could be identified as node-positive before surgery, which is of importance in the era of neoadjuvant therapy.[101]

Third, 2026 studies question the need for equally frequent ultrasound in current active surveillance programs after positive SLNB, as cross-sectional systemic imaging detects a significant proportion of recurrences and simultaneously evaluates distant organs.[102]

Thus, the direction of development can be described as a transition from “the more ultrasound, the better” to risk-adapted imaging – the choice of a specific visualization for a specific risk and clinical question. [103]

A special case: what does ocular melanoma look like on ultrasound?

For uveal melanoma, the situation is fundamentally different: ophthalmic ultrasound is one of the primary diagnostic methods. Therefore, the query "melanoma ultrasound" may have a completely different meaning if we are talking not about the skin, but about a tumor inside the eyeball. [104]

Uveal melanoma occurs in the choroid of the eye—most often in the choroid, less commonly in the ciliary body or iris. The 2026 ESMO-EURACAN guidelines state that the diagnosis of typical uveal melanoma is based on ophthalmoscopy, fundus photography, and traditional ocular ultrasound. [105]

Unlike cutaneous melanoma, biopsy is not always necessary for diagnosis of typical intraocular tumors. This is one of the most important differences between cutaneous and uveal melanoma. [106]

Ultrasound allows measurement of the thickness and basal diameter of an intraocular tumor and assessment of its position and extent. Higher-frequency ultrasound biomicroscopy is particularly useful for ciliary body melanoma. [107]

Therefore, the phrase "ultrasound does not diagnose melanoma" cannot be applied to uveal melanoma without further clarification. While this is true for common cutaneous melanoma, ophthalmic melanoma is a distinct disease with a distinct diagnostic algorithm. [108]

Question	Cutaneous melanoma	Uveal melanoma
The main role of ultrasound of the primary tumor	Additional	One of the main
Is it possible to confirm the diagnosis with a single routine ultrasound of the skin?	No	Typical ocular melanoma is often diagnosed clinically + ocular US
The main task of ultrasound	Thickness, lymph nodes, superficial metastases	Size and characteristics of the intraocular tumor
Biopsy for diagnosis	If cutaneous melanoma is suspected, histology is required.	Not always necessary
Breslow	Important	Not for use on skin

Source: ESMO-EURACAN Clinical Practice Guideline 2026, DOI 10.1016/j.esmoop.2026.106888. [109]

What to do if the ultrasound report says "suspected melanoma metastasis"

This conclusion indicates the need for morphological examination, rather than an established diagnosis of metastasis. The radiologist assesses the probability based on the combined size, shape, cortex, hilus, contours, and vascular pattern. [110]

If the lymph node is accessible, one of the usual next steps is a puncture or core biopsy under ultrasound guidance. This allows for examination of the suspect tissue. [111]

If morphology confirms metastasis, it is necessary to determine the full stage of the disease. For high-risk and regionally metastatic cutaneous melanoma, ultrasound alone is no longer sufficient – further imaging is selected according to the stage. [112]

If the biopsy is negative but the ultrasound remains highly suspicious, the physician may recommend a repeat or larger biopsy, surgical removal of the nodule, or additional imaging. The decision depends on how well the specimen represented the suspicious area. [113]

Don't compare lymph node sizes to "normal millimeter" figures found online. In melanoma, the internal architecture and dynamics of the node are often more important than the maximum diameter alone. [114]

Practical algorithm

1. If we are talking about a suspicious mole, start with a dermatologist and a dermatoscopy, not an ultrasound.
2. If melanoma is suspected, obtain tissue for histological examination.
3. After confirmation, find out the exact thickness according to Breslow and the stage.
4. If the stage indicates, examine the regional lymph nodes.
5. Suspicious node on ultrasound → targeted puncture or biopsy.
6. A negative ultrasound should not be used instead of SLNB if sentinel node biopsy is indicated.
7. At a higher stage, perform the prescribed systemic staging.
8. After treatment, follow an individual monitoring schedule.
9. A new subcutaneous node or enlarged lymph node should be examined unscheduled.

The current diagnostic algorithm for cutaneous melanoma is built around primary tumor histology, stage-based lymph node assessment, and systemic imaging in high-risk patients.[115]

When you need to see a doctor quickly

An unscheduled evaluation is necessary if, after treatment for melanoma, a new growing nodule appears in the skin or subcutaneous tissue, or a regional lymph node enlarges. Such symptoms do not automatically indicate a recurrence, but they do require verification. [116]

A new lump immediately adjacent to a surgical scar or between the scar and the regional lymphatic basin also requires examination, as this may indicate local, satellite, or in-transit recurrences. [117]

If a person has not yet been diagnosed with melanoma and a new or changing suspicious mole appears, the first investigation should usually be a dermatoscopy rather than a stand-alone skin ultrasound.[118]

Emergency care is required not because of a "suspicious ultrasound" per se, but rather due to corresponding acute symptoms—for example, sudden, severe neurological deficits in a patient with advanced melanoma. In such situations, specialized neuroimaging, rather than ultrasound, is used to assess possible brain damage. [119]

What is often misunderstood

"A doctor can immediately tell from an ultrasound that a mole is melanoma." - No. Even a typical hypoechoic skin tumor lacks sufficient specificity; suspicion of cutaneous melanoma is confirmed by pathological examination. [120]

"If a melanoma isn't visible on an ultrasound, it's not there." - No. Particularly thin superficial tumors may be at the limit of the machine's resolution, and ultrasound itself is not a method for ruling out melanoma. [121]

"Ultrasound can accurately determine the Breslow thickness." - No. It can provide a preliminary estimate of the depth, but the final Breslow thickness is measured by a pathologist. [122]

"Normal lymph nodes on ultrasound mean the sentinel node is negative." - No. Ultrasound is not sensitive enough to detect small micrometastases. [123]

"Any round lymph node is a metastasis." - No. The totality of shape, cortex, chyle, contours, vascular pattern and clinical situation is assessed. [124]

"If a hypoechoic nodule is found, it is already cancer." - No. Hypoechogenicity is a descriptive ultrasound characteristic and occurs in various conditions. [125]

"An abdominal ultrasound is sufficient to check for metastases." - No. For high-risk melanoma, staging requires stage-appropriate systemic imaging techniques. [126]

"Ultrasound is useless because a biopsy is still needed." - No. The method is very useful for lymph nodes, superficial metastases, biopsy guidance, and dynamic observation. [127]

"With ocular melanoma, ultrasound also shows almost nothing." - Incorrect. With uveal melanoma, ocular ultrasound is one of the key methods for diagnosing and measuring the tumor. [128]

Frequently Asked Questions

Is melanoma visible on a regular ultrasound?

Some melanomas can be visualized, but standard ultrasound is not a reliable way to diagnose or rule out cutaneous melanoma. High-frequency transducers are much more informative for the skin itself. [129]

What color is melanoma on ultrasound?

On grayscale imaging, it often appears hypoechoic, meaning darker. This has no relation to the actual brown or black color of the skin lesion. [130]

Can melanoma be hyperechoic?

Ultrasound characteristics vary, so echogenicity cannot be used as a standalone diagnostic criterion. Hypoechoic tumors are most frequently described. [131]

Is it possible to distinguish melanoma from nevus using ultrasound?

Reliable - no. High-frequency ultrasound can provide additional morphological information, but it does not replace histological diagnosis. [132]

Can ultrasound measure the depth of melanoma?

Yes, tentatively. A modern meta-analysis shows good correlation of HFUS with histological thickness, especially for thicker tumors and high frequencies. [133]

Is the thickness on ultrasound true Breslow?

No. Breslow is established during histopathological examination of an invasive tumor. [134]

What does melanoma metastasis in a lymph node look like?

Most commonly, suspicion is raised by rounding, hypoechoic cortex, disappearance of chyle, irregular contours, and abnormal blood flow. No single sign is absolute. [135]

If the ultrasound of the lymph nodes is normal, is it possible to skip the sentinel node procedure?

No, if SLNB is indicated based on the characteristics of the primary melanoma. A negative ultrasound may miss micrometastasis. [136]

How well does ultrasound detect occult metastases before SLNB?

Sensitivity is limited. In a 2026 meta-analysis, the pooled sensitivity was approximately 33.6%. [137]

What to do if a lymph node is suspicious on ultrasound?

Morphological examination is usually required. An accessible node can be punctured or biopsied under ultrasound guidance. [138]

Is it necessary to do an ultrasound of the lymph nodes after melanoma removal?

It depends on the stage. The European consensus includes lymph node sonography starting from stage IB, but other surveillance programs may differ. [139]

Are in-transit metastases visible on ultrasound?

Yes, superficial lesions are often readily visible on ultrasound. They may appear as hypoechoic nodules in the skin or subcutaneous tissue. [140]

Can liver ultrasound rule out melanoma metastases?

No. Normal abdominal ultrasound does not replace systemic staging with computed tomography, positron emission tomography, or magnetic resonance imaging when indicated. [141]

Which is better for melanoma - ultrasound or PET-CT?

They are designed for different purposes. Ultrasound is particularly useful for superficial lymph nodes, while PET-CT is used for the systemic search for metastatic disease in appropriate patients. [142]

Is ocular melanoma diagnosed using ultrasound?

Yes, with uveal melanoma, ocular ultrasound is one of the key diagnostic and tumor measurement methods. This is a distinct disease and a distinct situation compared to cutaneous melanoma. [143]

Key points from experts

Claus Garbe is a professor at the University Dermatology Clinic of Tübingen and one of Europe's leading specialists in dermato-oncology. His university profile confirms his affiliation with the University Hospital of Tübingen and his long-standing work in the field of melanoma research. [144]

The European multidisciplinary guideline, of which Garbe is the first author, emphasizes the fundamental distinction: suspicion of primary melanoma must be confirmed histopathologically, whereas lymph node sonography is already used as part of stage-oriented assessment and surveillance. [145]

Eric R. Tkaczyk, MD, PhD, FAAD is an Associate Professor of Dermatology at Vanderbilt University and Director of the Vanderbilt Dermatology Translational Research Clinic; his research focuses on noninvasive skin imaging technologies. [146]

Tkaczyk is a co-author of a 2025 meta-analysis of high-frequency ultrasound. The work shows that ultrasound measurement of melanoma thickness can correlate well with histology, but accuracy depends significantly on transducer frequency and tumor depth; therefore, HFUS should be considered an additional preoperative tool rather than a replacement for pathological Breslow.[147]

Philippe Saiag is a dermatologist-oncologist at the Hôpital Ambroise-Paré, Assistance Publique-Hôpitaux de Paris. His official AP-HP profile confirms his specialization in dermatology and venereology and his work in the general and oncological dermatology service. [148]

In a classic meta-analysis by Saiag's group, ultrasound was superior to palpation in detecting regional nodal metastases. This principle remains the foundation of the modern role of ultrasound: it is particularly valuable not for diagnosing a primary mole, but for more sensitive monitoring of accessible regional lymphatic basins. [149]

Main

When it comes to skin melanoma, ultrasound is an auxiliary, not a definitive, diagnostic method. A suspicious mole requires dermatoscopy and, if there are appropriate signs, histological examination; a normal skin ultrasound does not rule out melanoma. [150]

High-frequency ultrasound can provide a fairly accurate preliminary measurement of the depth of many invasive melanomas, especially when high frequencies are used and the tumor is not very thin. However, the final Breslow thickness remains a pathological measurement. [151]

The most practical role of ultrasound is in regional lymph nodes. Metastasis may manifest as node rounding, hypoechoic cortex, loss of chyle, irregular contours, and abnormal blood flow; a suspicious node can be immediately aspirated under ultrasound guidance. [152]

A negative lymph node examination should not be used as a substitute for sentinel node biopsy if indicated. A 2026 meta-analysis confirms the low sensitivity of ultrasound specifically for occult microscopic metastases. [153]

At a higher stage, ultrasound becomes only part of the overall imaging system: computed tomography and positron emission tomography are used to search for distant metastases, and magnetic resonance imaging is used for the brain. [154]

An exception is uveal melanoma of the eye. In this case, ophthalmic ultrasound is indeed one of the primary diagnostic and measurement methods for the primary tumor, so it is always important to clarify whether the melanoma is cutaneous or intraocular. [155]