Primary signet ring cell carcinoma of the eyelid: report of a case demonstrating further analogy to lobular carcinoma of the breast with a literature review.

Primary signet ring cell carcinoma of the eyelid is a rare neoplasm with less than ten cases described. This report details another case, which shows further parallels to lobular carcinoma of the breast, and reviews the literature on this subject. A 73-year-old white female presented with diffuse induration of her left eyelids. Histopathology revealed a delicate infiltrate of epithelial cells scattered throughout the lid stroma in a non-destructive pattern. The cells were relatively monomorphous and showed only mild atypia and rare mitotic figures. Many had slightly granular amphophilic cytoplasms, others showed distinct signet ring cell morphology, and all were strongly positive for epithelial mucin. Immunomicroscopy showed strong reactivity for estrogen receptor (ER), progesterone receptor (PR) and gross cystic disease fluid protein-15 (GCDFP-15), and was negative for Her-2/neu (erb-2) and cytokeratin 20. An extensive workup for other primary sites was negative. Orbital exenteration showed extensive involvement of both lids and soft tissue, including diffuse muscle and lacrimal gland infiltration. In the breast, signet ring cell carcinoma is considered a variant of lobular carcinoma. The delicate infiltrating pattern in our case and the ER+, PR+, GCDFP-15+, Her-2/neu-phenotype further strengthen this analogy. Together, these data also support apocrine differentiation of primary eyelid signet ring cell carcinoma.