Malignant pilomatricoma: causes, symptoms, diagnosis, treatment

Fungi-positive pilocarcoma (syn: pelomatocarcinoma, calcified epitheliocarcinoma, malignant pilomatrixoma, trichomatous carcinoma, pilomatrix carcinoma) is a very rare tumor that appears as a nodule usually on the skin of the trunk or extremities in middle-aged people and has no pathognomonic clinical signs.

Pathomorphology of malignant pyloricarcoma. Under the epidermis, often eroded, in the dermis are located different sizes and configurations of matrix cell complexes, often reaching the subcutaneous adipose tissue. Inside the complexes, foci of necrosis are often seen. The second population of tumor cells is the so-called shadow cells, which in some places form a natural continuation of the matrix cell complexes, and in some places separate structures form. Neoplastic matrix cells are characterized by the presence of atypical nuclei, nucleoli and large-dispersed chromatin. The figures of mitoses are frequent, including pathological ones. The third population of cells in the malignant pyloric coma can be melanonites.

Differential diagnosis should be made with pyloricarcoma. Fertilized pyloric coma is not associated with the funnel epithelium, does not have a cyst-like appearance, is not surrounded by a denser connective tissue. In the pyloric coma, as it evolves, the shadow cells begin to predominate over the matrix cells, almost completely replacing them in the final stages. In malignant cells, matrix cells predominate at all stages of development and are surrounded by dense lymphocytic infiltrates that are absent in the pyloric coma.