Rhabdomyosarcoma

Rhabdomyosarcoma is a malignant tumor originating from a skeletal (transverse striated) muscle.

ICD-10 code

• C48. Malignant neoplasm of retroperitoneal space and peritoneum.
• C49. Malignant neoplasm of other types of connective and soft tissues.

Epidemiology

The share of rhabdomyosarcoma accounts for about half of all cases of soft-tissue sarcomas in children. It accounts for 10% of the total oncological pathology of childhood. In the incidence of this tumor, two age peaks are singled out - in 1-7 and 15-20 years. The first coincides with the period of manifestation of congenital malignant neoplasms of childhood - neuroblastoma and nephroblastoma, the second - with a typical age of diagnosis of malignant bone tumors.

[1], [2], [3], [4], [5], [6], [7], [8]

Rhabdomyosarcoma and hereditary syndromes

In about a third of cases, rhabdomyosarcoma is combined with various developmental defects: the urinary tract (8%). CNS (8%), digestive system (5%), cardiovascular system (4%). In 4% of cases, additional spleen is detected, in 1% - hemygypertrophy. Rhabdomyosarcoma can be found in syndromes that predispose to the development of malignant neoplasms - Beckwita-Wendemannia, Li-Fraumeni (determines the high incidence of malignant tumors in family members: associated with a mutation of the p53 gene). Recliquhausen. Rubinstein-Teibi (combination of dwarfism and oligophrenia with hypertelorism, facial asymmetry, beak-like nose, abnormal bite, gillermetropia, astigmatism, characteristic shortening and thickening of the thumbs of the hands and feet, and often with other abnormalities of the skeleton and internal organs).

Symptoms of rhabdomyosarcoma

Rhabdomyosarcoma can be localized in any area of the body, including in the absence of skeletal muscles (for example, the bladder, bile ducts). For this neoplasm is characterized by lymphogenous and hematogenous (in the lungs, bone, bone marrow) metastasis.

Localization of rhabdomyosarcomas in the head and neck region and in the genito-urinary tract is more often detected in children under 10 years of age, while for adolescents, neoplasm of the extremities, trunk and paratesticular rhabdomyosarcomas are characteristic.

Classification of rhabdomyosarcoma

Histological structure and histological clamification

Rhabdomyosarcoma develops in the striated muscle tissue, as well as in such smooth muscle anatomical formations as the bladder, vagina, prostate, and seminal cord. The source of growth of rhabdomyosarcoma is not the mature skeletal musculature, but the immature mesenchymal tissue, its predecessor. Conditions for the emergence of rhabdomyosarcoma arise, for example, in the zone of the urinary bladder triangle as a result of mixing of meeodermal and ectodermal tissues in this area or in the region of the head and neck, where there are disturbances in the development of the derivatives of branchial arches. There are several histological types of rhabdomyosarcoma.

• Embryonic rhabdomyosarcoma (57% of all rhabdomyosarcomas) histologically resembles the structure of the skeletal musculature of a 7-10 week old fetus. It is characterized by loss of heterozygosity of the locus 11p15, which leads to loss of maternal genetic information and duplication of paternal genetic material. This variant is mainly observed in patients aged 3-12 years. Rhabdomyosarcoma affects the head and neck, orbit, genitourinary tract.
• The botryoid variant (6%) of embryonic rhabdomyosarcoma is characterized by the presence of polypoid or "groatslike" masses localized inside organs covered with mucous membranes, and in body cavities. Neoplasm is met at the age of 8 years. Localized in the bladder, vagina, nasopharynx.
• Alveolar rhabdomyosarcoma (9%) is histologically similar to the skeletal muscle cells of a 10-21 week old fetus. It is characterized by the translocation t (2; 13) (q3S; ql4). Neoplasm usually affects the limbs, the trunk, in adolescents - the perineum. Meet her at the age of 5 to 21 years.
• Pleomorphic rhabdomyosarcoma (1%) is histologically not similar to the fetal muscular tissue, affects the trunk and limbs, children are rarely found.
• Undifferentiated rhabdomyosarcoma (10%) arises from mesenchymal cells with no signs of differentiation, is localized in the extremities and trunk, is met in children under 1 year old.
• For rhabdomyosarcomas, which can not be attributed to any of the above options, account for 7%. Histologically, these neoplasms are heterogeneous. Localized in the limbs and trunk, meet them in patients aged 6 to 21 years.

In rhabdomyosarcomas, chromosomal abnormalities such as 5q +: 9q +: 16p +: 12p +: del (l) are also detected: and hyperdiploidy with multiple copies of 2.6.8. 12,13,18,20,21. The prognosis for diploid tumors is worse than hyperdiploid tumors.

[9], [10], [11], [12], [13], [14], [15], [16]

Clinical staging

With rhabdomyosarcoma and other soft tissue sarcomas, the staging of the TNM system is used at the preoperative stage (Tables 66-20).

In TNM-classification classification of T3 and T4 categories is not provided. The presence of more than one neoplasm is considered as a primary tumor and its distant metastases. In modern protocols for the treatment of soft-tissue sarcomas for their staging at the stage after a radical surgery or biopsy, the classification of the IRS (Intergroup Rhabdomyosarcoma Study) and postoperative pT staging

[17], [18], [19]

Diagnosis of rhabdomyosarcoma

Symptoms of rhabdomyosarcoma and other soft tissue sarcomas depend to the greatest extent on their localization.

• When the neoplasm is located in the limbs, there is a palpable tumor formation that causes the deficit of the limb and disrupts its function. Education is usually quite dense, its palpation does not cause noticeable soreness.
• With the localization of the neoplasm in the retroperitoneal space, there are pains in the abdomen, its increase and asymmetry, symptoms of compression of the intestine and urinary tract.
• In case of localization of the neoplasm in the trunk, head, neck area, the neoplasm can be identified by physical examination: defecation of the affected part of the body, restriction of movements in this area. At the same time, rhabdomyosarcoma of the neck can be combined with voice coarsening and dysphagia, nasopharyngeal neoplasms with local pain, epistaxis, dysphagia, paranasal sinus tumors with local pain and edema, sinusitis, unilateral discharge and nasal bleeding, rhabdomyosarcoma of the middle ear with chronic otitis with purulent and hemorrhagic secretions, the presence of polypand masses in the external auditory course, peripheral paralysis of the facial nerve, rhabdomyosarcoma of the orbit - with ptosis, strabismus, lower visual acuity.
• Neoplasms of paramagnetial localizations are accompanied by paralysis of the facial nerves, meningeal signs, respiratory insufficiency due to the invasion of the tumor into the brain stem.
• Pelvic neoplasm is accompanied by obstruction of the intestine and urinary tract. With tumors of the urinary tract, a violation of the passage of urine is noted, down to its acute delay; a strong formation can be palpated above the lobe. With neoplasms of the bladder and prostate, in some cases there is a macrohematuria. For tumors of the vagina and uterus are characterized by vaginal bleeding, the presence of vaginal groatslike tumor masses. With neoplasms of the epididymis, its growth and soreness are noted. Laboratory and instrumental studies

The diagnosis of soft tissue sarcoma is based on the morphological verification of the diagnosis. However, before it is carried out, an assessment of the primary tumor focus and localization of possible metastases is necessary. In the diagnosis of the primary tumor focus in the diagnostic plan include studies that are applicable for this localization of rhabdomyosarcoma: radiography, ultrasound, RCT and MRI, excretory urography, and histography, etc. Diagnosis of possible metastases is performed according to the standard plan, proceeding from the localizations of metastases localized in sarcoma soft tissues. Perform chest radiography and thoracic angiography, a radioisotope study of the skeleton, a study of the myelogram. Ultrasound of regional lymph nodes.

[20], [21], [22]

Mandatory and additional studies of patients with malignant tumors of soft tissues

Compulsory diagnostic tests

• Complete physical examination with assessment of local status
• Clinical blood test
• Clinical analysis of urine
• Biochemical blood test (electrolytes, total protein, liver tests, creatine, urea, lactate dehydrogenase, alkaline phosphates, phosphoric-calcium exchange)
• Coagulogram
• Ultrasound of the affected area
• Radiography of the chest cavity in five projections (straight, two side, two oblique)
• Ultrasound of the abdominal cavity and retroperitoneal space
• Bone puncture from two points
• Scintigraphy (RID) of the bone system
• ECG
• Echocardiography
• The final stage is a biopsy (or complete removal) for verifying a histological diagnosis. It is advisable to make prints from a biopsy for a cytological study

[23], [24], [25], [26],

Additional diagnostic tests

• When suspected of lung metastases
• TCC of the thoracic cavity
• If there is a suspicion of involvement of bone structures in the process - the radiography of the bones of this anatomical region in two projections (direct and lateral with the seizure of the above and lower joints
• When metastases are detected in other bones according to
• RID-aimed radiography of the affected foci or RCT of the indicated areas
• If there is a suspicion of a brain metastasis - EchoEG and PKT of the brain
• Ultrasound of regional lymph nodes in case of suspected metastatic lesion
• Renoscintigraphy with revealed renal dysfunction
• With the localization of rhabdomyosarcoma in the soft tissues of the limb - MRI of the affected limb
• Ultrasound color duplex angioscanning of the vessels of the affected limb
• Angiography of the limb (according to indications)
• When localized in the bladder:
  • cystoscopy with possible biopsy;
  • excretory urography;
  • uroflowmetry
• With paramagnealing localizations:
  • ENT examination;
  • ophthalmologic examination;
  • cytological examination of cerebrospinal fluid;
  • RKT / MRI of the brain

[27], [28], [29]

Treatment of rhabdomyosarcoma

The treatment of rhabdomyosarcoma is complex. It includes chemotherapy, radical surgery and radiotherapy. Modern chemotherapy programs use such cytostatics as alhilating agents (ifosfamide, cyclophosphamide), vinca alkaloids (vincristine), anthraniline antibiotics (doxorubicin), actinomycin-D, topoisocarase inhibitors (etoposide), platinum preparations (carboplatin).

Surgical treatment of rhabdomyosarcoma should be carried out, guided by the general principle of surgical radicalism. With initially unresectable neoplasms, the first stage should be a biopsy. This allows us to subsequently avoid repeated local growth of the tumor from its macro- or microscopic remains, which is especially important for localizations in the head, neck, orbit. In some cases, even after effective polychemotherapy, rhabdomyosarcoma may remain unresectable (neoplasm of nasopharynx, parameneginal localization). In this case, surgical treatment is not indicated, local control is performed by means of conservative chemoradiotherapy.

When the tumor is localized in the soft tissues of the limbs, a significant amount of lesion and involvement of the neurovascular bundle in the neoplasm are possible. In such cases, despite the absence of signs of the spread of the malignant process to the bone structures, the only radical is the organo-carrying operation. Operations with the preservation of the limb are carried out either after reducing the size of the tumor as a result of chemotherapy, or initially with small tumors that have clear boundaries with ultrasound and PKT / MRI.

In the case of an isolated lesion of the rhabdomyosarcoma of the bottom of the bladder (other parts from the tumor are free), with a good response to chemotherapy, a resection of the bladder wall is possible. In most cases, the bladder is affected either completely, or rhabdomyosarcoma is localized in the region of the urinary bladder, so there is a need for bladder extirpation followed by surgical reconstruction of the urinary outflow pathways. The optimal tactic of one-stage surgical treatment in oncopediatric practice should be considered ureterosigmostomiyu. In contrast to both ureterokutaneostomii, and the one-stage formation of complex artificial urinary reservoirs from various parts of the intestinal tube. Against the backdrop of chemotherapy in the first case, the risk of ascending infection with the development of bilateral pyelonephritis is great, and in the second case, the incompleteness of the formed reservoir is due to the reduced regeneration ability of tissues against the background of the action of cytostatic agents. As an alternative, a tactic with initial ureterocutaneostomy and a subsequent (several months after the end of chemoradiotherapy) stage of the formation of an official urinary reservoir is possible.

Paratesticular neoplasms are removed together with the testicle and the spermatic cord from the inguinal access (orhofunkullectomy). With rhabdomyosarcoma of the uterus, its extirpation is shown, with a vaginal tumor - removal of the vagina. With neoplasms affecting both these organs, the uterus and vagina are removed with a single block with a tumor.

Pulmonary metastases with their resectability are subject to surgical removal. Bone metastases due to their fatalities for prognosis should not be deleted.

Radiation therapy with rhabdomyosarcoma is performed in accordance with the criteria determined by the specific treatment program. The dose of irradiation depends on the location or metastases.

High-dose chemotherapy with bone marrow transplantation is prescribed for patients with high-risk rhabdomyosarcomas: in stage IV.

What prognosis does rhabdomyosarcoma have?

Rhabdomyosarcoma is associated with a relatively favorable prognosis: at stage I, up to 80% of patients survive, and at II - up to 65%. At III - up to 40%. IV stage is associated, as a rule, with a fatal prognosis. The prognosis is better with the embryonic type (up to 70%) in comparison with the alveolar and other types (50-60%). The prognosis worsens with the increase in the size of the neoplasm at the time of diagnosis (usually take into account: more or less than 5 cm the size of the tumor in the largest dimension). Depending on the location of rhabdomyosarcoma, favorable and unfavorable localizations are identified. The prognosis for unfavorable localizations is worse than when favorable; nevertheless it is not fatal. Favorable localizations include the orbit, the paratesticular region, the superficial regions of the head and neck, the vulva, the vagina, the uterus. Adverse localizations include the trunk, limbs, bladder, prostate, thoracic and abdominal cavities, deep regions of the head and neck. The best outcomes are observed in children under 7 years old compared with the older ones. This is associated with both a decrease in the frequency of the embryonic type of rhabdomyosarcoma, and with an increase in the frequency of common forms with the age of the patients. The prognosis for local relapse after program treatment, including after a radical surgery, is usually fatal.