Pediatric Solitary Plasmacytoma

Abstract

Solitary plasmacytoma of bone (SPB) is a localized plasma cell neoplasm. SPB accounts for 5 10% of all plasma cell dyscrasias ( 1 -3). The relationship of SPB to multiple myeloma continues to be controversial. Many authors believe that SPB is an early stage of multiple myeloma ( I . 3-5). whereas others consider i t as a distinct clinical entity (6, 7). The occurrence of SPB in younger age groups and involvement of long bones is very rare. The youngest patient reported in the literature is 16 years old. Here we report a 15-year-old girl with SPB of the humerus with 10 yrars follow-up. She still remains in remission. Case report. A 15-year-old girl presented in March 1986 with a history of left shoulder joint pain of 6 months' duration. Pain appeared mainly on lifting the limb above the head. There was no history of any Trauma or swelling of the joint. On examination she was moderately built and nourished. There was no pallor or lymphadenopathy and no tenderness or swelling of the joint. Movements of the joint were full. A healed scar was seen over the anterior part of the left shoulder. Systemic examination did not reveal any abnormality. Suspecting a bone tumor open biopsy with curettage and bone grafting was performed in a peripheral hospital. She was later referred to us for further management. Investigations revealed Hb of 135 g/l. TLC of 7.5 x 109/1, platelets 300 x 109/l. and ESR 40 mm/lst hour. Urine analysis was normal. An x-ray of the shoulder joint showed osteolytic areas with ill-defined borders in the medial part of the head of the humerus (Figure). The biopsy showed mainly plasma cells in an amorphous background of which some were binucleate but the majority were mature. A few immature plasma cells were noted. In view of the plasma cell neoplasm she was investigated further for evidence of any systemic disease. However, skeletal survey, serum electrophoresis, immunoglobulin quantitation. bone marrow aspiration and biopsy were all normal. Bone scan showed a solitary lesion in the left humerus. In view of the isolated plasma cell tumor the diagnosis of solitary plasmacytoma of the bone was considered. She was treated with local radiotherapy-42 Gy in 14 fractions. The treatment was well tolerated. She has been followed up for the last 10 years and is still in remission. Discussion. Plasma cell neoplasma may be either localized (solitary plasmacytoma) or generalized (multiple myeloma). Solitary plasmacytoma may arise either in bone (solitary plasmacytoma of bone-SPB) or in extramedullary tissues. SPB accounts for 510% of patients with plasma cell neoplasm ( 1-3).