Transformation of Primary Small Intestinal Follicular Lymphoma to CD20-Negative Diffuse Large B-Cell Lymphoma following Rituximab Treatment: A Case Report.

ABSTRACT:

Introduction

Follicular lymphoma is an indolent B-cell lymphoma that can involve the gastrointestinal tract, most commonly the small intestine. Although rituximab-based therapy is effective, transformation to diffuse large B-cell lymphoma (DLBCL) can occur and becomes difficult to diagnose after CD20 loss.

Case presentation

We report the case of a 64-year-old woman initially diagnosed with primary small intestinal follicular lymphoma who subsequently developed transformation to DLBCL 2 years after rituximab therapy. Double-balloon enteroscopy revealed progression of mucosal lesions, raising suspicion of histologic transformation. However, endoscopic biopsy was inconclusive because of the loss of CD20 expression, likely resulting from prior rituximab therapy. Surgical resecti

SUBMITTER: Kitamura M 

PROVIDER: S-EPMC12659653 | biostudies-literature | 2025 Jan-Dec

REPOSITORIES: biostudies-literature