Primary Gastrointestinal Follicular Lymphoma Exclusively Confined to the Mucosa.

Follicular lymphoma (FL) is a common form of non-Hodgkin's lymphoma that rarely occurs in the gastrointestinal (GI) tract. The majority of GI FL cases are indolent in nature and are incidentally detected. They arise in the duodenum and more specifically near the ampulla of Vater. Multiple lesions are usually present upon endoscopic examination with mucosal and submucosal involvement. We hereby report the rare diagnosis of primary GI FL that presented as a solitary lesion exclusively involving the mucosal layer of the GI tract and was not located in the classic periampullary region of the duodenum, using a combination of advanced endoscopic techniques.