Syringomatous carcinoma of the eyelid and orbit: a clinical and histopathological challenge.

AIMS: To present three patients with a syringomatous carcinoma (SC). SC 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, keratin filled cysts, and granular structures.
METHODS: The clinical histories of the patients with a SC were investigated retrospectively.
RESULTS: Patient 1 had a benign appearing tumour of the lower eyelid. Five tumour excisions were necessary to remove the SC completely. Patient 2 had a tumour on the lateral part of the lower eyelid and in the medial canthal area. The histopathological findings revealed a squamous cell carcinoma, later revised as a SC. In spite of two excisions and one microscopically controlled excision, a recurrence occurred. An exenteration orbitae was recommended. Patient 3, known to have a history of multiple malignant skin tumours after kidney transplantation and use of cyclosporin, presented with a firm mass in the eyebrow region and in the nasal area of the orbit. The pathological diagnosis of this adnexal tumour was difficult. An exenteration was recommended.
CONCLUSIONS: SC is a benign appearing but extremely invasive, locally destructive, 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.