A Rare Case of Colorectal Peripheral T-Cell Lymphoma Associated with Mycosis Fungoides

Abstract

Purpose: ‘Mycosis Fungoides' (MF) is an indolent T cell lymphoma, involving primarily skin with rare extracutaneous, or visceral involvement occurring in advanced stages of the disease. Gastrointestinal system involvement is very rare and it is associated with significant morbidity and mortality secondary to various complications. We are describing a case of “Peripheral T-Cell Lymphoma” involving the rectum and the colon diagnosed on a screening colonoscopy in a patient with a history of Mycosis Fungoides. A 66-year-old AA man with h/o of HTN, dyslipidemia, and mycosis fungoides was referred by his dermatologist for a screening colonoscopy. He denied any symptoms including weight loss, rectal bleeding, melena, hematemesis or altered bowel movements. His physical exam was notable for diffuse hypopigmented and hyperpigmented patches over the skin, primarily hands and feet. There was no evidence of splenomegaly or lymphadenopathy. He was lost to follow up for five years after a decade of stable disease. He was started on clobetasol topical ointment and narrow band UVB therapy. Colonoscopy showed a large ulcerated mass with greenish black exudate occupying 50-74% of the circumference of the rectum, extending 5cm from entry site up to 17cm. The biopsy showed colonic mucosa diffusely infiltrated by large atypical lymphoid cells with varied size, hyperchromatic nuclei and small nucleoli. Flow cytometry showed abnormal clonal T cell proliferation and stained positive for CD3, CD4, CD5 and rarely for CD8 suggestive of peripheral T cell lymphoma. A molecular study for TCR Gamma rearrangement performed on the previous lymph node biopsy and the current rectal specimen showed identical clonal peaks indicating that the process in the rectum likely represents transformation of the patient's cutaneous T cell lymphoma. A month later, he was admitted to the hospital with severe pain and swelling in his right lower extremity. He was found to be having a diffuse systemic involvement of T cell lymphoma of plural fluid, right thigh, inguinal lymphnodes, and CNS. His prognosis was assessed to be very poor and he was sent to hospice care based on his wishes for comfort care.Figure: No Caption available.