Primary Mantle Cell Lymphoma of Rectum with Rare Presentation: A Unique Case Report and Review of Literature

Abstract

Background: Primary Mantle Cell Lymphoma (MCL) is an infrequent subtype of aggressive B-cell non-Hodgkin's lymphoma, representing a small fraction of all lymphomas. Primary gastrointestinal B cell lymphomas are a rare subset of B cell lymphomas and are characterized by their aggressive behaviour and an unusual chromosomal rearrangement (11;14) with overexpression of cyclin D1. The initial presentation of primary MCL as rectal nodules is an exceptionally uncommon, and sparsely documented in medical literature. Case Report: A 59-year-old male patient who presented with symptoms of rectal bleeding, constipation, and abdominal pain that persisted for four months is the subject of this case report. A subsequent colonoscopy revealed distinct features such as edema, loss of vascularity, nodularity, and central ulceration encircling the rectal region. A punch biopsy was performed on the affected area, followed by a comprehensive histopathological examination. Based on the distinctive histomorphology and immunohistochemistry findings of the biopsy specimen, a diagnosis of MCL was conclusively established. Conclusion: This case serves as a reminder that lymphoproliferative neoplasms, including MCL, should be included in the differential diagnosis for patients who present with rectal bleeding and rectal nodularity, especially in older individuals. Immunohistochemistry plays a vital role in the definitive diagnosis, as clinical symptoms and colonoscopy findings may mimic those of rectal cancer.