Amyloid Secreting Jejunal Plasmacytoma

A 58 years old male patient with no known co-morbidities presented with history of chronic anemia and abdominal lump for 3 years. CT scan of abdomen showed a 9 cm segmental circumferential asymmetric jejunal mural thickening with mild luminal narrowing with post contrast enhancement. He underwent exploratory laparotomy, resection of jejunal segment and primary anastomosis. Histopathological examination from the growth showed diffuse sheets of plasmacytoid cells (positive for CD138, Kappa and negative for Lambda) with many areas showing extracellular and perivascular amorphous eosinophilic material deposition which was congo red positive and revealed apple green birefringence under polarised light (Fig. 1). Bone marrow aspiration revealed 3% plasma cells. PET CT revealed coalescent mesenteric nodes of size 5.9 × 5.4 cm (SUV max 9.5) but no FDG avid lesions elsewhere in the body. No monoclonal band was seen but serum free light chain assay was abnormal (Kappa 134.5 mg/dl and Lambda 19.15 mg/dl; ratio 7.02). Cardiac 2D ECHO and NT-ProBNP were normal. A diagnosis of amyloid secreting jejunal plasmacytoma was made. He was treated with Bortezomib, lenalidomide and Dexamethasone protocol and achieved complete hematologic remission. He is off treatment and in complete hematologic remission after 3 years of follow up. Extramedullary plasmacytomas (EMP) comprise about 3% of plasma cell neoplasms. They occur most commonly in upper respiratory tract including the paranasal sinuses. Only 5–10% EMP occur in gastrointestinal tract mostly in stomach [1]. Extramedullary intestinal plasmacytoma with amyloidosis is a very rare occurrence [2]. Of all of the plasma cell neoplasms, EMPs have the best prognosis. However, these patients need to be followed up on regular basis for the development of amyloidosis and progression to multiple myeloma.

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