Track: Case Reports

Abstract:

Endocrine mucin-producing sweat gland carcinoma is a type of sweat gland carcinoma with characteristic neuroendocrine differentiation and mucin production. These neoplasms most often affect the face, with the lower eyelid being the most common site. Most follow an indolent clinical course; however, some can progress to cutaneous mucinous carcinoma. It is important to differentiate this entity from other common lesions of the eyelid, such as basal cell carcinoma, and hidrocystoma, as well as metastatic mucin-producing adenocarcinomas and neuroendocrine tumors. 

 We present a case of an 83-year-old man with a history of a composite resection and subsequent radiation for squamous cell carcinoma of the oral cavity presenting with a pearly papule on the lower eyelid. A biopsy of the lesion showed sheet-like growth of monotonous, intermediate sized, basaloid cells with occasional pools of mucin. The cells stained positive with INSM1, and a diagnosis of endocrine mucin producing sweat gland carcinoma was rendered.  

Prompt and accurate diagnosis of this tumor helps guide clinical management and follow-up for patients. Endocrine mucin-producing sweat gland carcinomas have a high rate of local recurrence, and Mohs surgery has been increasingly used to obtain negative margins for these tumors. While differentiating a solitary pearly nodule of the eyelid can be a challenge, endocrine mucin-producing sweat gland carcinoma is an important entity for pathologists and clinicians to consider in the differential diagnosis.