Aspiration cytology of signet-ring cell lymphoma. A case report.

BACKGROUND: Signet-ring cell lymphoma is a rare subtype of non-Hodgkin's lymphoma, composed of vacuolated cells with a signet-ring cell appearance. We found only two cases that had been reported as diagnosed by fine needle aspiration biopsy. CASE: A 61-year-old female had signet-ring cell lymphoma diagnosed by computed tomography-guided aspiration biopsy. Smears of aspirates from her retroperitoneal mass contained a population of small to medium-sized, angular lymphoid cells; lymphoglandular bodies; and an abundance of signet-ring cells. The signet-ring cells were negative for cytokeratin and positive for leukocyte common antigen and CD20, a B-cell marker. Monoclonality for lambda light chain determinant was noted, and a diagnosis of signet-ring cell lymphoma of the B-cell type was made. A core biopsy specimen confirmed the diagnosis. CONCLUSION: Signet-ring cell lymphoma should always be considered in the differential diagnosis of tumors composed of signet-ring cells.