S3445 Microscopic Enteritis: A Rare Manifestation of T-cell Promyelocytic Leukemia

Abstract

Introduction: An abnormal infiltration of intraepithelial lymphocytes in the intestinal mucosa is described as microscopic enteritis (ME). ME is a heterogeneous condition that can be found in, but not limited to, celiac disease, autoimmune disorders, food protein intolerance, parasitic infections, and NSAID use. Thus, an obvious cause of ME is difficult to elucidate and requires thorough work up. We report a case of a patient who was found to have ME thought to be secondary to infiltrative T-cell promyelocytic leukemia (T-PLL). Case Description/Methods: A 68-year-old male with a history of type II diabetes and hyperlipidemia presented with intermittent fever, abdominal pain, nausea, and emesis. He was found to have small bowel obstruction with severe enteritis of 3/4 of the small bowel (distal jejunum to the ileocecal valve). He had a small bowel resection with pathology revealing necrotizing lymphocytic enteritis. Bidirectional endoscopy revealed mild colonic, ileal and duodenal edema with biopsies revealing increased intraepithelial lymphocytes. He was empirically treated with intravenous methylprednisolone with resolution of fevers. He was discharged home with a follow up with gastroenterology for ME and with hematology for persistent leukocytosis. He continued to have recurrent fevers with persistent lymphocytic leukocytosis (14,200 WBC/microliter). Infectious (acid fast bacteria, fungi, cytomegalovirus, adenovirus, syphilis) and rheumatologic diagnostics were unrevealing. He underwent bone marrow biopsy and peripheral blood examination with immunostains, flow cytometry, and cytogenetic studies and was found to have clonal T-cell receptor gamma gene rearrangement concerning for T-PLL. He was treated with alemtuzumab; however developed worsening disease and disseminating opportunistic infections (cytomegalovirus and aspergillosis). He passed away shortly after his diagnosis. Discussion: ME is a challenging diagnosis as its etiology can be difficult to elucidate. Prompt, timely evaluation should be prioritized to improve outcomes. T-PLL is a rare leukemia due to abnormal growth of T-lymphocytes and typically presents with leukocytosis, weight loss, and infection; however, gastrointestinal symptoms may be a presenting symptom.