Toxic megacolon: a rare presentation of primary lymphoma of the colon.

Primary colonic lymphoma is rare and accounts for less than 1% of colon malignancies. Moreover, diffuse neoplastic invasion of the colon is exceptional. This case describes a patient with primary non-Hodgkin's lymphoma of the colon presenting as toxic megacolon. This unique presentation is the first case reported in the literature of a diffuse colonic lymphoma diagnosed in the setting of a toxic megacolon. Histological confirmation was performed on the piece of colectomy.