Fine-needle aspiration cytology of adenoid (acantholytic) squamous-cell carcinoma.

Adenoid squamous-cell carcinoma (ASCCa) is an uncommon cancer which occurs most frequently in the skin of the head and neck region of elderly, sun-exposed individuals. Histologically, ASCCa is characterized by gland-like, "adenoid" cell groups with a central, detached acantholytic cellular component and an intact peripheral rim of cells. The cytological features of five fine-needle aspiration cytology (FNAC) samples from four patients with primary or metastatic ASCCa are presented. These were assessed for features which would allow distinction of this variant from conventional squamous carcinoma. The adenoid component was represented in FNAC by intact, sometimes three-dimensional cell groups simulating glandular structures. Also present were cells in short chains of two or three in single cell files and scattered, individual dyskeratotic cells. Individual cells had rounded, accentuated borders, cytoplasmic keratinization, and often pyknotic nuclei, representing acantholytic cells from the adenoid "lumens." Features of malignancy, including cellular atypia and increased mitotic rate, were present allowing for distinction between ASCCa and benign acantholytic processes such as pemphigus.