Signet-ring cell variant of small lymphocytic lymphoma with a prominent sinusoidal pattern.

Signet-ring cell lymphoma is a rare morphologic variant of non-Hodgkin's lymphoma characterized by neoplastic lymphoid cells with cytoplasmic vacuoles or eosinophilic globules that impart a signet-ring cell morphology. Although most cases are variants of follicular center B-cell lymphomas, this pattern also can be seen in T-cell lymphomas. An indolent clinical course and prolonged survival have characterized the majority of published cases. We document the case of a 62-year-old African-American woman with diffuse small lymphocytic signet-ring lymphoma having a predominant sinusoidal growth pattern, which, to our knowledge, has not been previously reported. The prominent sinusoidal pattern of signet-ring lymphocytes contributes to its confusion with metastatic signet-ring cell adenocarcinoma. The correct diagnosis is greatly facilitated by the use of appropriate immunohistochemical stains for lymphoid markers.