Signet ring cell carcinoma of the eyelid - the monocle tumour.

We report the clinical and histopathological characteristics of two cases of signet ring cell carcinoma of the eye lids, and discuss the histogenesis of this neoplasm. Two 72-year-old Caucasian males both presented with slowly growing tumours of the eyelids. The tumours were excised and specimens were examined using light- and transmission electron microscopic techniques. Clinically, the tumours infiltrated both eyelids on one side of the face with swelling and periocular inflammation, creating a monocle-like appearance. Extensive clinical work-up excluded periocular metastases. Histopathologically, the tumours were composed of rather bland cells with mainly histiocytoid morphology. A minor proportion had a signet ring cell appearance. The cytoplasmic inclusions giving the signet ring morphology were PAS- and colloidal iron positive. The tumour cells reacted with antibodies against cytokeratins, carcinoembryonic antigen, epithelial membrane antigen, gross cystic disease fluid protein-15 and lysozyme. Transmission electron microscopy demonstrated tumour cells containing intracytoplasmic vacuoles lined by microvilli. The tumour cells aggregated in duct-like clusters. A diagnosis of primary signet ring cell carcinoma was made in both cases. Histopathological, immunohistological and ultrastructural findings indicated that the tumours were of sweat gland origin.