Extramedullary Plasmacytoma of the Pancreas Diagnosed Using Endoscopic Ultrasonography-Guided Fine Needle Aspiration
A 58-year-old woman was transferred to our hospital for further evaluation of pelvic pain that was aggravated by walking and began approximately 2 months before admission. The initial laboratory tests showed a hemoglobin level of 10.6 g/dL, and blood urea nitrogen was 12.0 mg/dL. The results of liver function tests were within normal limits. The level of total protein level was 9.7 g/dL and the albumin level was 3.3 g/dL. A peripheral blood cell smear revealed mild lymphopenia. Skeletal surveys detected a small osteolytic lesion without a sclerotic rim in the left parietal bone and a large bone destructive osteolytic lesion in the right inferior pelvic bone (). Incisional biopsy of the right pelvic bone suggested a malignant bone tumor. The lesion was diagnosed as a plasmacytoma. Further evaluation showed a serum free light chain lambda level of 3,475.3 mg/L and a β2-microglobulin level of 4.6 mg/L. Immunoelectrophoresis showed the presence of an abnormal band of immunoglobulin G and lambda lanes. Plasma cells were 14.2% on bone marrow biopsy. Contrast-enhanced abdominal computed tomography (CT) revealed a suspicious ill-defined marginated mass in the body of the pancreas (). To further characterize the lesion, magnetic resonance imaging (MRI) of the pancreas was performed. T2-weighted MRI indicated that the pancreatic proximal body contained a mass of subtle high signal intensity () with marked diffusion restriction (). For the histopathologic diagnosis, EUS-FNA was planned. Linear EUS (EU-ME1 Ultrasound System; Olympus, Tokyo, Japan) (GF-UCT 240; Olympus) revealed a 1.2×1.0-cm sized, hypoechoic, heterogeneous, well-defined round mass in the pancreatic body (); FNA was performed via a transgastric approach and five passages were made with a 22-gauge needle (EchoTip Ultra, ECHO-22; Cook Endoscopy, Winston-Salem, NC, USA) (). The cytopatholgy results showed a small cell neoplasm and the immunohistochemical profile was compatible with plasmacytoma (). The patient began combination therapy consisting of bortezomib, mephalan, and prednisolone with local radiation therapy for the right pelvic bone lesion. The patient was followed up carefully.