NCIt definition : A rare aggressive adnexal carcinoma that arises from the eyelid. It often affects
both the upper and lower eyelids and manifests with painless swelling, usually in
elderly males. 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.;