Synchronous presentation of Gaucher disease and solitary plasmacytoma with progression to multiple myeloma

A 37-year-old Polish immigrant presented with unilateral hip pain and difficulty weight-bearing. Plain radiography and magnetic resonance imaging (MRI) revealed a lytic lesion in the acetabulum, with abnormal serum electrophoresis and bone marrow biopsy. The patient was diagnosed with two rare conditions presenting synchronously - Gaucher disease and plasmacytoma. He was treated with enzyme therapy and radiotherapy, but subsequently developed a recurrence of plasmacytoma in the right femur, confirmed with bone marrow biopsy. This was also treated with radiotherapy, followed by a retrograde femoral nail to reduce the risk of pathological fracture. The patient went on to develop multiple lytic lesions in the ribs and vertebra, seen on MRI. Further bone marrow biopsy confirmed dissemination of the plasmacytoma into multiple myeloma, for which he was treated with systemic chemotherapy. In patients presenting with refractory bone or joint pain, haematological and histological investigations should be considered to exclude less common diagnoses.