Histiocytoid variant of eccrine sweat gland carcinoma of the eyelid and orbit: Report of five cases

Objective: To study the clinicopathologic features of the histiocytoid variant of adenocarcinoma of the eccrine sweat gland of the eye and orbit. Design: Retrospective case series. Participants: Five patients undergoing orbital and eyelid biopsy as a diagnostic procedure. Methods: The authors examined the clinical histories and pathologic findings of five patients with eccrine adenocarcinoma of the eyelid with orbital invasion. Main Outcome Measures: Clinical and histopathologic examinations, including routine histopathology, immunohistochemistry, and electron microscopy studies. Results: The tumors presented as insidious, diffusely infiltrative, firm cutaneous masses in the periocular area that later infiltrated the orbit. Histopathologic examination revealed that the tumors infiltrated the dermis and were composed of cells with a histiocytic to signet ring appearance. Tumor cells exhibited intracellular mucin production. Immunohistochemical stains were positive in tumor cells for low and high molecular weight cytokeratins, carcinoembryonic antigen, and epithelial membrane antigen. Electron microscopic examination showed lumen formation and intracytoplasmic mucin in tumor cells. Conclusions: The histiocytoid variant of adenocarcinoma of the eccrine sweat gland of the eyelid may present as an insidious tumor and diffusely invade the orbit. These cases may be confused with metastatio adenocarcinoma.