2157 A Novel Case of Plasma Cell Leukemia Diagnosed by Endoscopic Ultrasound With Fine-Needle Biopsy

Abstract

INTRODUCTION: There are numerous reports of endoscopic ultrasound (EUS) with fine needle aspiration (FNA) used to diagnose plasmacytoma of the GI tract but, to our knowledge, this is the first report of plasma cell leukemia diagnosed by EUS with fine needle biopsy (FNB). CASE DESCRIPTION/METHODS: A 78 year old woman presented with exertional chest pain, dyspnea, and unquantified unintentional weight loss. CT chest showed bilateral pleural effusions, left pleural soft tissue masses, and multiple paravertebral soft tissue masses. Thoracentesis was non-diagnostic. She re-presented a month later with the same symptoms. Repeat imaging revealed enlargement of the lesions and the decision was made to pursue EUS-FNB to obtain tissue for diagnosis. On endoscopy, the patient was found to have gastric erosions and two non-bleeding, ulcerated nodules in the fundus. Biopsies resulted in chronic gastritis and h.pylori. EUS described one enlarged lymph node visualized in the middle para-esophageal mediastinum, surrounded by hyperechoic hazy soft tissue. The lymph node measured 30.6 mm by 18.5 mm, with irregular, poorly defined margins. A second lymph node was found in the peri-pancreatic region, measuring 19.4 mm × 15 mm. FNB was performed. The pathology report from both nodes identified sheets of atypical plasma cell proliferation which stained positive for CD138 and CD56. Flow cytometry revealed a proportion of 40% IgG Lambda-restricted plasma cell population. These findings, taken in the context of a known M-spike and circulating atypical IgG lambda-restricted plasma cells on peripheral blood smear, established the diagnosis of plasma cell leukemia with soft tissue component. Unfortunately, it was felt that the patient would not be able to tolerate chemotherapy and she was sent home with hospice. DISCUSSION: While EUS-FNA is used frequently to evaluate lesions in the upper GI tract, this is the first reported case, to our knowledge, of EUS-FNB used to diagnose a plasma cell leukemia. In this case, the diagnosis was confirmed, not on peripheral smear or with cytology from pleural fluid, but from the biopsies we obtained. This is a good example of how EUS-FNB can often be the safest and easiest way to obtain adequate tissue samples from intrathoracic or intraabdominal lesions to facilitate diagnosis.