Primary mucinous eccrine adenocarcinoma: A rare skin adnexal tumor at an unusual site

The extracellular mucin was periodic acid Schiff (PAS) and Alcian blue positive [Figure 2]a and [Figure 2]b. On immunohistochemistry, the tumor cells were positive for CK 7 and negative for CK 20 which supported the eccrine origin of the tumor [Figure 2]c and [Figure 2]d. The final histopathological diagnosis of primary eccrine mucinous adenocarcinoma was given. Metastatic tumors from breast and colon most closely mimic primary eccrine mucinous carcinoma of the skin. [...]primary mucinous eccrine carcinoma of the skin should be considered in the differential diagnosis of mucinous carcinoma on aspiration cytology of subcutaneous masses even at rare sites such as periumbilical region.