Primary Cutaneous NUT Adnexal Carcinoma

**Semantic type:** Neoplastic Process

**Definition:** A very rare carcinoma that arises from the sweat glands. It is characterized by mutations and rearrangement of the NUT gene. It presents as a papular or nodular skin lesion and has been described in the hand, shoulder, trunk, and lower limb. Histologically, there is a proliferation of malignant epithelial cells in the dermis and/or subcutaneous tissue. The tumor cells display round nuclei with prominent single nucleoli. Features include the presence of small round ducts and foci of abrupt keratinization.

**Synonyms:** - NUT Adnexal Carcinoma - NUT Sweat Gland Carcinoma - Primary Cutaneous NUT Sweat Gland Carcinoma