Mucin-producing sweat gland carcinoma of the eyelid: diagnostic and prognostic considerations.

PURPOSE: To describe the clinical and pathologic characteristics of mucin-producing sweat gland carcinoma of the eyelid and to determine whether neuroendocrine differentiation is of prognostic significance.
DESIGN: Retrospective interventional case series.
METHODS: Search of the New York Eye and Ear Infirmary pathology database between 1990 and 2011 identified 16 patients with mucin-producing sweat gland carcinoma. Clinical, histopathologic, and immunohistochemical analyses were performed on all identified cases.
RESULTS: The patients presented with vascularized, focally cystic, nonulcerated eyelid margin lesions. Histopathologic evaluation showed that 4 lesions (25%) had a cystic, papillary, and solid growth pattern with an in situ component, 7 (44%) were pure invasive mucinous carcinomas, and 5 (31%) demonstrated both growth patterns. Immunohistochemical analysis of 15 tumors showed that pure cystic/papillary lesions had a significantly greater percentage of synaptophysin-immunoreactive cells (P = .036). There was no significant difference in the number of neuroendocrine markers expressed or in the intensity of immunostaining among the 3 different growth patterns. Re-excision for margin clearance was performed in 8 of 13 cases (61.5%). Two of 13 lesions recurred (15%); 1 of these was an in situ tumor with cystic morphology and neuroendocrine differentiation and the other was pure invasive mucinous carcinoma. None of the lesions metastasized.
CONCLUSIONS: Mucin-producing sweat gland carcinoma pathologically represents a continuum, from an in situ lesion to a classic, invasive mucinous carcinoma. Immunohistochemical evidence of neuroendocrine differentiation can be observed in all lesions and does not appear to have a prognostic significance, arguing against the utility of immunohistochemical subtyping of mucinous sweat gland carcinomas.