Beginning >> Diseases >> Tumors >> Pilomatrikoma


Pilomatrikoma — a benign tumor, gistogenetichesk connected with cells of a matrix of a hair follicle.


Pilomatrikoma meets more often at children's and youthful age. Family cases are occasionally observed.

Etiology and pathogeny

Histochemical and electronic microscopically it is proved that tumor cells represent cells of an unripe hair matrix.
Sharply positive reaction to SS-and SH groups in the majority of cells of a tumor and double refraction of cells shadows in the polarizing microscope testify to a tendency to keratinization.
Transitional cellular elements between matriksny cells and cells shadows are analogs of hair, those at normal keratinization, they contain a large number of tonofibrils, and in them there is no keratogialinovy stage of keratinization.

Clinical signs and symptoms

The tumor is localized mainly on a face, upper extremities or in the field of a shoulder girdle.
At early stages of development of a pilomatrikom it is characterized by prompt growth, creating a small knot of 0,5 in size — 0,8 cm in 1 — 1,5 month. A small knot with a smooth or lobular surface, a dense and elastic consistence, with a yellowish shade.
The phase of rapid growth is replaced by a phase of slow growth, and the node within several years can reach the size of several centimeters, getting at the same time a stony and dense consistence.
At emergence of a pilomatrikoma in a wall of a hair cyst it is long the existing tumor it is provided by a node with a thin wall at which palpation fluctuation is defined, and contains in a cavity petrifikat.

The diagnosis and the recommended clinical trials

The diagnosis is made on the basis of clinical inspection and results of a biopsy.
Characteristic pathomorphologic sign of a pilomatrikoma at early stages of development is availability of massive layers of small roundish cells with dark basphilic kernels and almost indiscernible cytoplasm — typical cells of a hair matrix. Within these accumulations islands of gradual transformation of matriksny cells in larger cells with faintly painted cytoplasm with indistinct borders and pyknotic, gradually disappearing kernels are visible owing to what they received the name of "cells shadows". The tumor stroma at the first stages is rich with vessels.
In more mature educations accumulations of cells shadows prevail, the vascular component is expressed poorly and processes of dystrophy with presence of huge multinuclear macrophages and deposits of salts of calcium which in the form of small granular masses are in cells shadows prevail or are located in the form of the amorphous masses which is coming to light by Kossa's method. In 15 — 20% of cases ossification is observed.
Among islands of the pale-painted cells with symptoms of dystrophy often find accumulations of an unripe keratin, and also the pigmented cells of a hair bulb. The pilomatrikoma can sometimes arise in a wall of a hair cyst.

Differential diagnosis of a pilomatrikoma

Hair cyst, skin calcification, skin osteoma.

General principles of treatment

Surgical excision, electroexcision are shown.


"Papillary syringadenoma   Piokokkovy granuloma"