Primary Colorectal Follicular Lymphoma Observed by Magnifying Endoscopy, with a Five-year Follow-up.

Colorectal involvement is very rare in cases of follicular lymphoma. Colonoscopy of a 69-year-old man revealed an aggregation of multiple whitish nodules in the sigmoid colon. Magnifying endoscopy with narrow-band imaging demonstrated a coiled and elongated microvascular pattern on the surface and crystal violet staining showed a type I pit pattern. A biopsy showed follicular lymphoma (Grade 1), and no other involvement of lymphoma was detected. Following a diagnosis of primary colorectal follicular lymphoma stage I (Lugano classification), the patient was monitored by watch-and-wait therapy. We documented the endoscopic images of colorectal follicular lymphoma in the present case.