Endorectal sonographic appearances of rectal MALT lymphoma, its response to therapy, and local recurrence.

Endorectal sonography may significantly help to evaluate rectal lymphoma. We report the sonographic findings in a case of rectal non-Hodgkin's MALT (mucosa-associated lymphoid tissue) lymphoma, including the monitoring of response to therapy and confirmation of recurrence, in a 45-year-old man. On endorectal sonography of the rectal wall, the mucosa was markedly thickened to 1.1 cm and was diffusely hypoechoic and risen into multiple polypoid folds. The submucosa and muscularis propria appeared normal. Multiple lymph nodes were visualized in the perirectal fat; they were homogeneously hypoechoic, were round or oval, and ranged from 1.0 cm to 2.6 cm. Endoscopic biopsies revealed a grade I non-Hodgkin's MALT lymphoma. Following chemotherapy, endorectal sonography showed that the surface of the rectal mucosa had a smoother appearance and near-normal thickness, but lymph nodes, although smaller, remained visible in the perirectal fat. Four months later, endorectal sonography demonstrated a local relapse of disease, with significant thickening of the rectal mucosa and multiple lymph nodes visible in the perirectal fat. Following high-dose chemotherapy for the recurrence, endorectal sonography demonstrated a near-normal appearance of the rectal mucosa.