Syringomatous carcinoma: Case report of a rare tumor entity

Abstract

Syringomatous carcinoma is a rare cutaneous neoplasm, most frequently situated on the face and scalp and histologically characterised by an
infiltrative pattern of basaloid or squamous cells, a desmoplastic stromal reaction and keratin filled cysts. We report the case of a 76-year-old
woman who presented an ulcerative interscapular lesion measuring 3x4cm. After resection, the histological examinations of the specimens have
identified a basal cell carcinoma. However, a local recurrence was observed 18 months later; histopathological findings showed a syringomatous
pattern and neoplastic epithelial cells arranged in interconnecting cords with microcystic areas. Nests, cords, and tubules of the tumour extended
into the dermis and into the adjacent muscle. Sclerosis of stroma around the cords was present. Tumour cells were not connected to the epidermis. The immunohistochemical analysis showed positivity for anti-CK7, AE1/AE3 and negativity for anti CEA and anti CK20. These histological and immunohistochemical analyses were consistent with the diagnosis of syringomatous eccrine carcinoma. Syringomatous carcinoma is an extremely invasive tumor, locally destructive and slowly growing adnexal tumour, derived from eccrine sweat glands. It is often mistaken, both clinically and microscopically, for other benign and malignant entities. The tumour recurrence is high due to extensive perineural invasion, but
regional or distant metastases are rare. The local aggressive nature of the tumour and the high recurrence rate may necessitate mutilating procedures. Optimal treatment consists of a complete microscopically controlled surgical excision with clear surgical margins.

Key words: Syringomatous carcinoma, histopathology, immunohistochemistry, differential diagnosis