Signet Ring Cell/Histiocytoid Carcinoma

**Semantic type:** Neoplastic Process

**Definition:** A rare aggressive adnexal carcinoma that affects the eyelid and rarely the axilla. Morphologically, it is characterized by the presence of signet ring cells or histiocytoid epithelial cells with eosinophilic cytoplasm infiltrating the dermis and subcutis, often in a single file pattern.

**Synonyms:** - SRCHC - Signet-Ring Cell/Histiocytoid Carcinoma