576 Journal of the College of Physicians and Surgeons Pakistan 2008, Vol. 18 (9): 576-577 INTRODUCTION Plasma cell neoplasms represent a spectrum of diseases characterized by clonal proliferation and accumulation of terminally differentiated B cells. The spectrum includes conditions as benign as Monoclonal Gammopathy of Undetermined Significance (MGUS); indolent conditions like Waldenström’s macroglobu- linemia and more malignant disorders like multiple myeloma and plasma cell leukemia. These disorders share a common feature of production of single monoclonal peak (M component) on serum protein electrophoresis. Among patients with multiple myeloma, 70% have their M component comprising IgG and 20% having IgA. Production of monoclonal light chains only represents 5 - 10%. Less than 1% of patients produce monoclonal IgD, IgE, IgM or have non-secretory myeloma. 1 Multiple myeloma is diagnosed on the basis of major and minor criteria comprising tissue diagnosis, monoclonal gammopathy, bone marrow plasmacytosis, lytic bone lesions, and suppressed uninvolved immunoglobulin. 2 More recently, International Staging System (ISS) for multiple myeloma has been established on the basis of beta-2 microglobulin and serum albumin levels. 3 We are presenting a case report of non-secretory myeloma, which is a rare variant in the spectrum of plasma cell neoplasms. CASE REPORT A 42-year-old male presented to our department with history of a lump at the upper part of sternum present for the last two years. The swelling was small in size to begin with but enlarged slowly over time. Patient complained of slight pain in the lump for about two months with generalized weakness. There was no associated history of fever, cough, headache, abdominal pain, or any other lump. On examination, there was a lump at the manubrium sternii; about 4 x 3 cm in size, mildly tender, immobile and firm in consistency. The baseline blood picture with differentials, renal and liver function tests and uric acid levels were essentially normal. Chest X-ray revealed multiple small lytic lesions involving especially both scapulae and clavicles. Ultrasound abdomen was normal except for mild fatty infiltration of liver. CT scan of the chest showed an expansile lytic lesion involving manubrium sternii with extraosseous extension. There were also lytic expansile lesions involving right 3 rd , 4 th , and left 6 th ribs and the thoracic spine. The lump was excised, which turned out to be a plasmacytoma on histopathology. Bone marrow biopsy was normal with plasma cells representing only 4%. Serum protein electrophoresis was essentially normal. Quantitative immunoglobulins were then performed which showed IgG (8.42 g/dl), IgA (1.28 g/dl) and IgM (0.41 g/dl) to be within normal limits. Urine test was negative for Bence Jones protein. Other relevant findings were raised levels of beta-2 microglobulin (ß2M, 3478 ng/ml) and low levels of serum albumin (2.6 g/dl). Serum calcium was markedly raised at 14.5 mg/dl. X-ray skull revealed multiple punched out lesions of varying sizes. Final diagnosis of non-secretory myeloma was made as it fulfilled one major criterion of tissue diagnosis of plasmacytoma and one minor criterion of multiple lytic lesions in the skeleton. ABSTRACT The spectrum of plasma cell neoplasm represents indolent conditions like Monoclonal Gammopathy of Undetermined Significance (MGUS) to more aggressive multiple myeloma and plasma cell leukemia. Non-secretory myeloma comprises less than 01% of this spectrum where serum protein electrophoresis and quantitative immunoglobulins remain essentially normal. We are presenting a case report of this rare variant involving the sternum of an adult male. Key words: Multiple myeloma. Plasma cell neoplasm. Non-secretory myeloma. 1 Department of Medical Oncology and Hematology, Shifa International Hospital, Islamabad. 2 Department of Pathology, Shifa International Hospital, Islamabad. Correspondence: Dr. Col. (R) Saleem Siddiqui, House No. 30, Nazim-ud-Din Road, F-8/1, Islamabad, Pakistan Received September 22, 2006; accepted August 7, 2008. Non-Secretory Myeloma: A Rare Variant of Multiple Myeloma Khurshid Ahmed Khan 1 , Nauman Saleem Siddiqui 1 , Ayesha Junaid 2 and Saleem Siddiqui 1 CASE REPORT