Laryngeal fibroma

One of the varieties of laryngeal tumor formations is laryngeal fibroma, a tumor of connective tissue that is classified as a mesenchymal tumor.

Fibrous neoplasms of the larynx are detected quite rarely and, despite their benign nature, they can be locally aggressive, and under the influence of various unfavorable factors, their malignant transformation cannot be ruled out. [ 1 ]

Epidemiology

Among benign lesions of the larynx, tumors account for 26% of cases; the main contingent of patients are males (men are affected six times more often than women) in the age range from 30 to 60 years.

Up to 70% of benign tumors are localized in the glottis, 25% in the supraglottic and 5% in the peripharyngeal zones.

The remaining formations, according to clinical statistics, turn out to be inflammatory pseudotumors (formed as a result of hyperplasia of lymphoid tissue or proliferation of spindle-shaped cells with a pronounced inflammatory infiltrate).

Primary benign fibrous histiocytoma of the lower larynx (localized from the vocal cords to the beginning of the trachea) occurs in only 1% of middle-aged patients with laryngeal tumors.

Causes laryngeal fibroma

Depending on the cause of occurrence, laryngeal fibromas are divided into the main types: congenital and acquired. In the first case, the supposed causes of the appearance of fibrous formations of this localization are considered by specialists to be a genetically determined predisposition of the body, viral and bacterial infections of the expectant mother, as well as teratogenic effects during the period of ontogenesis (intrauterine development), leading to mutation of the germ cell. [ 2 ]

In the second case, risk factors for the formation of laryngeal fibroma at the junction of the middle and anterior thirds of the vocal cords include:

• increased stress on the vocal cords caused by the need to speak loudly and for a long time;
• smoking and alcohol abuse;
• irritation of the larynx from inhaled vapors, gases, and finely dispersed substances (which is often associated with poor production or general environmental conditions);
• exposure to inhaled allergens;
• long-term inflammatory processes affecting the laryngopharynx, in particular, chronic laryngitis, chronic pharyngitis or catarrhal tonsillitis, etc.;
• persistent nasal breathing disorder;
• irritating effect on the mucous membrane of the larynx of acids of the stomach contents due to gastroesophageal reflux in the presence of GERD - gastroesophageal reflux disease or extraesophageal reflux;
• chemical burns of the larynx;
• history of endocrine and systemic connective tissue diseases.

Some medications, such as antihistamines (used for allergies), cause a loss of moisture from the mucous membranes, which can lead to further irritation and/or increased sensitivity of the larynx and vocal folds.

Taking into account histology, such types of formations as myo and elastofibroma can be distinguished, and according to their consistency - soft or dense fibromas. Laryngeal polyps are also considered a type of fibroma.

In addition, very rare, so-called desmoid fibromas include aggressively growing fibroblastic formations of unknown origin (with local infiltration and frequent relapses). [ 3 ]

For more details see – Benign tumors of the larynx

Pathogenesis

In most cases, laryngeal fibromas are solitary, round-shaped formations (often pedunculated, that is, having a “stalk”), up to 5 to 20 mm in size, consisting of fibroblasts of mature fibrous tissue (originating from embryonic mesenchyme) and located on the mucous vocal folds (plica vocalis) inside the larynx, commonly called the vocal cords.

Explaining the pathogenesis of laryngeal fibroma formation, specialists note the anatomical features and morphological characteristics of the vocal fold tissues. They are covered with stratified squamous epithelium on top, with ciliated pseudostratified epithelium (consisting of mucinous and serous layers) located below; the submucosal basement membrane, the lamina propria, lies deeper, formed by layers of lipopolysaccharide macromolecules, as well as cells of loose connective tissue consisting of amorphous fibrous proteins and interstitial glycoproteins (fibronectin, fibromodulin, decorin, versican, aggrecan).

The connection of cells with the extracellular matrix – to ensure the elastic biomechanical properties of the vocal fold during its vibration – is maintained by hemidesmosomes of the basal plates and collagen and elastin fibers, interspersed with fibroblasts, myofibroblasts and macrophages.

Any tissue alteration activates cytokines and kinins, fibroblast growth factors (FGFs), platelet-derived growth factor (PDGF), etc., and as a result of fibroblast and macrophage activation, an inflammatory reaction develops and connective tissue cell proliferation begins at the site of damage. And their induced proliferation leads to the formation of a connective tissue tumor – fibroma.

Symptoms laryngeal fibroma

The first signs of a fibroma that has formed in the larynx are a disorder of voice formation: hoarseness, huskiness, changes in the timbre of the voice and its strength.

As otolaryngologists note, clinical symptoms of benign laryngeal tumors can vary from mild hoarseness to life-threatening respiratory distress and most often manifest as:

• sensation of a foreign body or lump in the throat;
• weakening (increased fatigue) of the voice during conversation;
• the appearance of a dry cough;
• shortness of breath.

Complications and consequences

The larger the size of the neoplasm, the higher the likelihood of complications such as:

• stridor (noisy breathing) and difficulty breathing - due to narrowing of the lumen of a separate section of the larynx;
• problems with swallowing - dysphagia;
• obstruction of the glottis with loss of voice (aphonia).

Diagnostics laryngeal fibroma

Otolaryngologists record the patient's complaints, examine the laryngopharynx and conduct a functional study of the larynx.

Instrumental diagnostics – visualization of laryngeal structures using laryngoscopy and laryngeal stroboscopy, as well as CT and MRI – is a key diagnostic method.

Diagnostic fibroscopy allows obtaining a sample of tumor tissue for its histomorphological evaluation.

Differential diagnosis

Differential diagnosis is carried out with cysts, myxomas, fibromyomas and fibrosarcomas of the larynx, as well as with carcinomas - laryngeal cancer.

It is necessary to differentiate between vocal nodules or vocal fold nodules (nodular or fibrous chorditis, code J38.2 according to MK-10), which are classified as diseases of the vocal cords and larynx and are considered tumor-like polypous formations of connective tissue. [ 4 ]

Treatment laryngeal fibroma

In case of laryngeal fibroma, only surgical treatment is performed.

Today, removal of laryngeal fibroma is performed using the method of electro- and cryodestruction, as well as – as a method of choice – endoscopic laser exposure (using a carbon dioxide laser). [ 5 ]

At the same time, according to some data, the rate of fibroma recurrence after laser surgery is about 16-20%. [ 6 ]

Prevention

The formation of laryngeal fibroma can be prevented by neutralizing risk factors such as smoking and alcohol abuse; it is also possible to reduce the load on the vocal cords, and in case of gas pollution in industrial premises, to use protective equipment.

Respiratory infections should be treated promptly to prevent them from becoming chronic.

Forecast

The prognosis for life of fibrous neoplasms of the larynx is positive, however, the possibility of their malignancy should be kept in mind.