Endoscopic ultrasound-guided fine-needle aspiration in the diagnosis of multiple myeloma accompanied by portal extramedullary plasmacytomas

Abstract

A 67-year-old man presented with plasmacytomas in the hepatic portal region, as diagnosed with endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). Laboratory blood tests showed no myeloma-related symptoms such as hypercalcemia, renal failure, and anemia, and normal levels of serum immunoglobulins. However, bone marrow examination demonstrated approximately 15% of atypical plasma cells in bone marrow mononuclear cells, and serum tests showed an abnormal serum free light-chain ratio and monoclonal protein of Bence Jones lambda upon immunoelectrophoresis. Positron emission tomography/computed tomography demonstrated high ¹⁸F-fluorodeoxyglucose uptake in the portal hepatic tumors and several bone lesions accompanied by osteolysis. The patient was treated with bortezomib plus dexamethasone followed by high-dose melphalan with autologous stem cell transplantation, resulting in a complete response. Lymph nodes are common sites of extramedullary myeloma disease associated with poor prognosis. EUS-FNA is less invasive than open surgical biopsies and thus it is recommended in the differential diagnosis of plasmacytoma in cases such as ours. EUS-FNA may enable early treatment, resulting in a good response even in myeloma patients with unfavorable prognoses.