Bence Jones myeloma with signet-ring-like plasma cells.

Abstract

Signet-ring cells, typical of muciparous adenocarcinoma, are seldom observed in other solid tumors or in lymphoproliferative disorders. Two cases of myeloma with signet-ring morphology have been reported so far. To the best of our knowledge, the following is the first case of signetring cell Bence-Jones myeloma. A 69-year-old man presented with cachexy, dehydration, liver enlargement and multinodular goiter. Blood tests revealed leukocytosis (12.9310/L), increased serum creatinine (130 μmol/L) and lactic dehydrogenase (534 U/L). Proteinuria (1 g/L), hypercalcemia (2.86 mmol/L) and hypogammaglobulinemia (7.81 g/L) were also present. Serum concentrations of tissue polypeptidic antigen (177 U/L), thyroglobulin (261 μmg/L), and b2-microglobulin (5.39 mg/L) were increased, while carcinoembryogenic antigen, a-fetoprotein, calcitonin, CA 199 and prostate-specific antigen were normal. Briefly, chest X-ray, esophagogastroduodenoscopy, echography and needle aspirate of the thyroid, and echography and CT scan of the abdomen did not detect any solid tumor. Skeletal roentgenograms revealed a diffuse worm-eaten bone aspect, due to small multiple lytic lesions of the skull, vertebrae, pelvis and femora. Immunophoresis disclosed monoclonal l light chains in the urine and serum. Iliac bone marrow smear and trephine biopsy demonstrated an interstitial infiltrate of small lymphoplasmacytic elements and several larger cells that contained a broad single cytoplasmic vacuole displacing the nucleus to the periphery, conferring a signet ring-like appearance (Figure 1, A,B,C). Only l light chains were documented in both cell types by immunohistochemistry. The lymphoplasmacytes displayed an intense diffuse cytoplasmic pattern; signet-ring cells showed a similar reaction at the periphery of vacuoles and scanty positivity inside (Figure 1, D). Bence-Jones myeloma, esophagitis and non-toxic multinodular goiter were diagnosed. The patient experienced temporary benefit from treatment with clodronic acid, melphalan, prednisone. He died eighteen months later of cerebral hemorrhage. This case represents a rare morphological variant of an equally rare disorder. Both the peculiar signet-ring aspects, probably the result of an accumulation of material from defective immunoglobulin assemblage, and the presenting symptoms initially suggested a misleading diagnosis of solid tumor.