Skin leiomyoma: causes, symptoms, diagnosis, treatment

Leiomyoma of the skin (synonym: angioleyomioma) is a benign smooth muscle tumor.

There are three varieties of this tumor: leiomyoma, which develops from the muscle that lifts the hair; dentoid (genital), emanating from the smooth muscles of the scrotum, female external genital organs or muscles contracting the nipple of the mammary glands; Angioleiomyoma, developing from the muscle elements of small vessels of the skin.

Leiomyoma, which develops from the muscle that lifts the hair, is small, dense, reddish, reddish-brown or normal skin color, nodular or plaque-like elements, arranged in groups or linearly, on the limbs. As a rule, painful. The solitary leiomyoma has the same form, but the elements are much larger.

Causes and pathogenesis of skin leiomyoma. Accordingly, histogenesis is currently distinguished by 3 types of skin leiomyomas, characterized by characteristic of each of them clinical and histomorphological features.

• I type - multiple leiomyomas, developing from smooth, lifting hair, or diagonal muscles.
• Type II - dartoid (genital) solitary leiomyomas, developing from tunica dartos of the scrotum and smooth muscles of the breast nipples.
• III type - salts of angiomyleyomi, developing from the muscular walls of the closing arteries and smooth-muscle elements of the walls of small vessels.

Some scientists believe that leiomyoma is more a developmental disorder than neoplasm. There are single descriptions of family leiomyoma, which allows to consider this disease as genetically conditioned.

Symptoms of leiomyoma of the skin. Leiomyoma of the skin is common in men. Element of defeat is a hemispherical dense knot of round or oval shape, the size of a pinhead to a lentil, a large bean and more, stagnant red, brownish, bluish-reddish color. A characteristic feature of skin leiomyoma is their sharp soreness under the influence of mechanical irritation (rubbing clothes, scratching, pressure or touching) and cooling. The pain syndrome is caused by the pressure of the nerve cells by the leiomyoma. Unbearable pains are often accompanied by dilated pupils, lower blood pressure, blanching of the skin. Leiomyomas usually have a multiple character and are localized on the face, neck, trunk and extremities, are more likely to group.

Histopathology. Leiomyoma consists of intertwining bundles of smooth muscle fibers separated by connective tissue interlayers. Cells have hyperchromic nuclei, the number of vessels is reduced, and nerve fibers - increased.

Pathomorphology. The tumor node of this type of leiomyoma is clearly delineated from the surrounding dermis and consists of intertwined thick beams of smooth muscle fibers, between which there are narrow layers of connective tissue. When painting according to the Van Gyzon method, the muscle beams are dyed yellow, and the connective tissue is red. A tumor that develops from a diagonal mouse, without clear boundaries, has a similar structure, but the bundles of muscle fibers are somewhat thinner, lie more loosely. Between the muscle bundles in a poor connective tissue lie capillary vessels, sometimes with focal lymphohistiocytic infiltrates. There may be edema and dystrophic changes.

Leiomyoma dentoid is a single, painless brownish-red node about 2 cm in diameter. Histologically it differs little from a leiomyoma developing from a muscle lifting a hair.

Angioleyomioma usually solitary, slightly rising above the surface of the skin, covered with unchanged or reddish-cyanotic skin, painful on palpation. In a limited area, several elements may occur, localized more often on the limbs, mainly near the joints.

Pathomorphology. Angioleyomioma differs from other species by leiomyomas in that it consists of a dense intertwining of bundles of thin and short fibers, located randomly in places, in places in the form of concentric structures or vortices. In the tumor tissue, many cells with elongated nuclei, intensely stained with hematoxylin and eosin. Among these elements, many vessels with an indistinctly expressed muscular membrane directly passing into the tumor tissue are found, and therefore the vessels have the appearance of slits located between the bundles of muscle fibers. Depending on the nature of the prevailing vascular structures, four main types of angioliomyomia structure can be distinguished. The most common are angioleiomioma of arterial type, then venous and mixed, as well as malodifferentiated angioleiomyomas, in which few vessels are identified, mainly with slit lumens. In some angioleomiomas, one can see features of similarity to the Barre-Masson glomus angiomas. They are characterized by the presence of "epithelioid" cells, which constitute the bulk of the tumor. In later terms, angioleiomyoma can detect various secondary changes in the form of a sharp expansion of the vessels, proliferation of connective tissue, leading to sclerosis, hemorrhages, followed by the formation of hemosiderin.

Histogenesis. Electron microscopy showed that leiomyomas from the muscles that lift the hair consist of bundles of normal muscle cells. They have a centrally located nucleus, surrounded by an endoplasmic reticulum and mitochondria, and along the periphery a large number of myofilament beams. Each muscle cell is surrounded by a basal membrane. Among them, nerve fibers are found in the state of twisting and disintegration of the myelin layer, apparently as a result of compression by their muscle cells. Some authors attribute these nerve fibers to the soreness of these tumors, while others believe that soreness is the result of muscle contractions. A.K. Apatenko (1977), studying the histogenesis of angioleiomyomas, showed that the closing arteries are the source of development of this variety of tumors, as evidenced by the characteristic structure of the vessels (presence of the longitudinal muscle layer, epithelioid cells, stellate lumens) and morbidity.

Leiomyosarcoma is rare. Can occur at any age, including in the first months of life. Located in the deep layers of the skin, reaching a large size, sometimes significantly protrudes over the surface of the skin, occasionally ulcerated. It is often located on the lower limbs, then on the head and neck. The tumor is usually solitary, but there are also multiple tumors.

Pathomorphology. With a longer and less malignant course, the structure of the tumor resembles that of benign leiomyoma, differing from it by a marked proliferation of spindle-shaped elements and the presence of polymorphism of the nuclei. In a more malignant variant, a large number of anaplastic hyperchromic nuclei, located in groups forming multinuclear symplasts, a lot of unevenly scattered mitoses, as well as infiltrating growth into the underlying tissues, are detected in the tumor.

Differential diagnosis should be carried out with fibromas, angiomas, fibrosarcomas, epitheliomas, skin leiomyosarcomas, neurofibromas and other tumors.

Treatment of leiomyoma of the skin. Surgical or laser excision, cryotherapy, intravenous or intramuscular injections of prospidin, per course - 1 - 2.5 g. For multiple foci a good effect has a calcium antagonist - nifedipine.

[1], [2], [3], [4]