Malignant syringoma: causes, symptoms, diagnosis, treatment

Malignant syringoma (syn.: sclerosing carcinoma of the sweat gland duct, syringomatous carcinoma, microcystic adnexal carcinoma, syringoid eccrine carcinoma, eccrine epithelioma, basal cell epithelioma with eccrine differentiation, eccrine carcinoma with syringomatous structures, eccrine basalioma, etc.).

Based on literature data and their own observations, P. Abenoza and AB Ackerman (1990) came to the conclusion that all of these numerous names actually describe different degrees of differentiation of a single tumor process - tubular eccrine carcinoma, and proposed the term "syringomatous carcinoma of high, medium and low degree of differentiation" to designate this process.

This is a rare tumor that occurs equally often in men and women. The average age of patients is 45 years, the growth is relatively slow - years, occasionally - decades. 85% of malignant syringomas with high differentiation are localized on the skin of the face, especially often on the upper lip (35%), cheeks (16%), periorbitally (10%). In these places, compaction is noted, and subjectively patients indicate paresthesia. The tumor usually manifests itself as a solitary node or plaque with a smooth surface, 1-3 cm in diameter or more, ulceration may occur in long-existing elements. Areas of compaction when localized on the lip usually indicate transmural growth towards the mucous membrane.

Pathomorphology of malignant syringoma. The tumor is characterized by the presence of tubular structures in the central sections, as in syringoma, lined with bilayer epithelium; cysts with signs of keratinization, in some places with calcium salt deposits, violations of the integrity of the cystic wall and granulomatous reaction in the surrounding stroma. Along the periphery - cords of small dark cells with infiltrating growth in the dermis and subcutaneous adipose tissue. Some cords have emerging lumens. In the stroma surrounding the cords, metachromasia is revealed when stained with toluidine blue, and ultrastructural examination shows that the cells forming the cords have large nuclei, which is typical for processes of increased synthesis of nucleic acids. Sometimes tumor cells penetrate bundles of peripheral nerve fibers, adventitia of medium-caliber vessels and cause destruction of skin appendages. The literature describes observations of syringomatous carcinoma with a predominance of light cells rich in glycogen.

Syringomatous carcinoma of moderate differentiation, according to P. Abenoza, AB Ackerman (1990), occurs somewhat more often in women, the average age of patients is 61 years. The tumor exists for years, the predominant localization is the skin of the scalp, palms, back, lower extremities. Clinically it looks like a dense plaque with unclear boundaries up to 5 cm in diameter.

Pathomorphology. The tumor is characterized by the presence of nuclear atypia, the absence of keratinized cysts, ductal structures of irregular configuration and various sizes, solid or adenoid cystic clusters of basaloid cells.

In low-grade syringomatous carcinoma, typical "syringoid" structures are difficult to determine, nuclear atypia is sharply expressed, there are many mitotic figures, strands of tumor cells between bundles of collagen fibers of the dermis with single microfoci of tubular differentiation. The risk of metastasis is high. It is necessary to differentiate from carcinoma of any other localization, in particular, the mammary gland.

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