The patient was a 62-year-old man who presented with the chief complaints of diminished visual acuity in his right eye. Cranial magnetic resonance imaging revealed multiple osteoclastic tumors. Moreover, contrast-enhanced computed tomography revealed lesions in the pancreas and left thoracic wall. Endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) of the pancreatic lesion was performed using a 22-gauge needle, and multiple immunostaining assays were conducted. These findings led to the diagnosis of multiple myeloma with metastasis to the pancreas. Although, EUS-FNB is widely used as an effective endoscopic procedure to support pathological diagnoses of rare cancers, it is important to select the puncture needle for each case while carefully considering safety. We report a rare case in which extramedullary lesions associated with multiple myeloma were diagnosed based on pathological findings.
