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

ABSTRACT 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.