Report of a case: primary mucinous carcinoma of the skin.

Primary mucinous carcinoma of the skin is an extremely rare adnexal tumor that is thought to originate from eccrine sweat glands. The neoplasm usually arises on the head and neck, with the most commonly involved area being the periorbital region. The tumor is typically a solitary, asymptomatic nodule, cyst, or ulcer that is slow growing with low metastatic potential. However, post-excisional local recurrence is common, affecting up to 36 percent of patients. Since primary mucinous carcinoma of the skin is such a rare neoplasm (fewer than 130 cases have been reported to date), a complete workup should be conducted to rule out other internal malignancies that may metastasize to the skin. We report a case of primary mucinous carcinoma of the skin, and discuss the clinical presentation, histology, treatment, course, and prognosis.