B-CELL SIGNET-RING CELL LYMPHOMA OF BONE-MARROW

A case of signet-ring cell lymphoma affecting the bone marrow and diag nosed by bone marrow trephine biopsy is reported. Normal marrow was re placed totally by cells with large central vacuoles, many of which dis placed the nucleus to the periphery of the cell, imparting a signet-ri ng appearance. Initially, the favoured morphological diagnosis was met astatic signet-ring adenocarcinoma, but on immunocytochemistry the tum our cells were strongly positive for CD45 (leucocyte common antigen) a nd the B cell marker CD20 (L26). Electron microscopy revealed electron -lucent vacuoles with no discernable internal structure. The tumour wa s classified as a high grade centroblastic lymphoma using the upgraded Kiel classification. Despite chemotherapeutic treatment, the patient died during an episode of septicaemic shock within two months of prese ntation.