P0279 - A Rare Case of Primary Gastrointestinal Mantle Cell Lymphoma Hiding in Plain Sight as Colon Polyps

Suhib Alhaj Ali, MD¹, Polo Kostecki, DO¹, Muhammad Zarrar Khan, MD², Amit Bhan, MD^1
1Henry Ford Hospital, Detroit, MI; ²Henry Ford Hospital, Royal Oak, MI

Introduction: Mantle cell lymphoma (MCL) is an aggressive subtype of B cell non-Hodgkin lymphoma that constitutes only a small fraction (0.4%) of all primary gastrointestinal lymphomas. Patients with MCL have a high relapse rate and poor prognosis.

Case Description/Methods: A 71-year-old man presented with 6 months of non-specific symptoms including abdominal discomfort, altered bowel habits, and weight loss. Although he had a normal colonoscopy 4 years prior, a repeat endoscopic examination revealed significant lymphomatous polyposis, with hundreds of non-bleeding polyps localized from the rectum to the distal ascending colon. Histopathological assessment of the polyps revealed a lymphoid infiltrate consistent with MCL. Cytogenetic analysis of bone marrow aspirate along with imaging revealing extensive mesenteric and retroperitoneal adenopathy and a mildly enlarged spleen confirmed the MCL diagnosis. The patient underwent 6 cycles of bendamustine and rituximab followed by maintenance rituximab therapy every 2 months. Throughout and after treatment, serial imaging showed markedly reduced adenopathy, and colonoscopy performed 2 months post-treatment (prior to maintenance therapy) demonstrated completely normal colon without evidence of any residual polyps. One month after completing initial chemotherapy, an incidental complex renal lesion was diagnosed as clear-cell renal cell carcinoma (World Health Organization / International Society of Urologic Pathologists grade 1, 4 cm, limited to the kidney), and the patient underwent successful partial nephrectomy after completion of chemotherapy.

Discussion: Our case underscores the imperativeness of thorough endoscopic evaluation in patients with non-specific gastrointestinal symptoms to ensure early detection and effective management of rare colonic cancers. This is particularly important with classic “red-flag” symptoms and features suggesting malignancy and despite normal recent colonoscopies (as in our patient who had a normal colonoscopy 4 years prior). The case further highlights how quickly the rare condition of gastrointestinal MCL can arise, necessitating swift immunohistochemical, imaging, and cytogenetic analysis to identify this aggressive condition. Even with a delayed presentation and diagnosis, diligent and timely treatment can still result in significant disease remission. The co-occurrence of gastrointestinal MCL with renal cell carcinoma introduces additional complexity to the case and suggests a potential association warranting further study.



Disclosures:


Suhib Alhaj Ali, MD¹, Polo Kostecki, DO¹, Muhammad Zarrar Khan, MD², Amit Bhan, MD¹. P0279 - A Rare Case of Primary Gastrointestinal Mantle Cell Lymphoma Hiding in Plain Sight as Colon Polyps, ACG 2024 Annual Scientific Meeting Abstracts. Philadelphia, PA: American College of Gastroenterology.