Sclerosing Microcystic Adenocarcinoma: A Case Report and Review of Literature

Sclerosing microcystic adenocarcinoma is an extremely rare tumor that was described by Mills et al in 2016 and occurs in the head and neck region. There are 8 cases published with this terminology in the English language literature. Here, we present a 59-year-old female patient with sclerosing microcystic adenocarcinoma in the anterolateral tongue and review the previously reported 8 cases. Most of the reported cases are in females and localized to the tongue. This tumor mimics microcystic adnexal carcinoma, which is a cutaneous-based malignant tumor. The tumor in the present case was composed of cells that were arranged in nests or gland-like structures, with had ductular differentiation in a densely sclerotic stroma. The diagnosis of sclerosing microcystic adenocarcinoma may be difficult because of its paucicellular histomorphology. Surgical margins can be problematic to assess. Several salivary gland tumors should be included in the differential diagnosis, such as adenoid cystic carcinoma, polymorphic adenocarcinoma, and mucoepidermoid carcinoma. The role of immunohistochemistry in this differential diagnosis is limited. Therefore, the diagnosis depends on routine histology.