Case Report of a Rapidly Progressive Indolent T-Cell Lymphoma of the Gastrointestinal Tract.

Indolent T-cell lymphoma of the gastrointestinal tract (iTCL-GI) is a relatively newly recognized disease entity. iTCL-GI was first proposed by Perry et al. in 2013, before it was formally incorporated as a distinct disease category in the fifth edition of the World Health Organization Classification of Hematolymphoid Tumors: Lymphoid Neoplasms in 2022. Although the prognosis of iTCL-GI is generally favorable, some cases may present with malignant transformation or severe clinical manifestations. Herein, we describe a case of iTCL-GI with a poor clinical outcome. An 85-year-old female presented with chronic diarrhea and weight loss. Esophagogastroduodenoscopy and colonoscopy performed at the referring clinic were nondiagnostic, and the patient was referred to our institution. Balloon-assisted enteroscopy revealed multiple ulcerative lesions in the distal ileum, which were eventually diagnosed as iTCL-GI based on the biopsy findings. Palliative care was provided in accordance with the patient's preferences. Her gastrointestinal symptoms progressed rapidly, and she died 5 months after symptom onset. In this report, we discuss how balloon-assisted enteroscopy can be useful in the diagnosis of iTCL-GI, as well as a review of the literature on potential risk factors for poor clinical outcomes, including the presence of ulcers on endoscopy.