Sclerosing Signet Ring Cell Carcinoma of the Lacrimal Gland: A Potentially New Primary Entity.

An 88-year-old man presented with diplopia, limitation of extraocular movements, and a firm palpable mass in the superolateral orbit. Biopsy revealed a sclerosing signet ring cell carcinoma with histopathologic features mimicking those of a primary signet ring cell (histiocytoid) carcinoma of the eyelid of eccrine or apocrine gland origin, a metastasis from an invasive lobular breast carcinoma or a metastatic diffuse-type gastric carcinoma. An extensive panel of immunohistochemical stains and molecular genetic analyses unequivocally failed to establish a precise diagnosis. Electron microscopy demonstrated features of a primary lacrimal gland lesion with intracytoplasmic lumens and zymogen granules typical of lacrimal secretory pyramidal cells. A thorough initial systemic work-up failed to reveal a primary visceral malignancy. Fifteen months of follow-up have failed to detect the emergence of another primary malignancy. To the best of our knowledge, a tumor with the morphology of the current lesion has not been previously described in the major or accessory lacrimal glands.