Role of endosonography in rectal lymphoma.

Sir, Endoscopic ultrasonography (EUS) is widely applied in gastric lymphomas: it helps to distinguish lymphoma from carcinoma,1 to detect the degree of loco-regional involvement,1,2 to monitor response to radio-chemotherapy3,4 and to identify a recurrences4 early during follow-up evaluation. EUS could give the same informations when applied to the study of rectal lymphoma. Nevertheless, only few studies exist in literature5,6 on this subject, probably because this neoplasm is less frequently localized to the rectum. In this paper we describe a case of non-Hodgkin’s mucosa-associated rectal lymphoma. The aim of our work is to emphasize the role of EUS in the diagnosis and therapeutic planning of rectal lymphoma. A 45-year old man was referred to our hospital complaining of repeated rectal bleeding, mucous diarrhea and weakness lasting several months. At rectal examination the ampulla was completely occupied by a circumferential polypoid elevation, irregular in surface, friable, easily bleeding. We performed EUS, using biplanar, linear and sectorial probes. The rectal mucosa appeared markedly thickened, diffusely hypoechoic and raised in multiple polypi-like folds. The submucosa and the muscularis propria were normal. A great number of enlarged lymph nodes were scattered in the perirectal fat (Figure 1). Endoscopic biopsies showed a low-grade mucosa associated with nonHodgkin’s lymphoma, with small cleaved type B-cells (immunophenotype CD20/L26+, CD45RA/4KB5–, CD5–, CD3–, CD45R0/UCHL1–, CD4). The whole staging revealed widespread disease in the bone marrow with lymph node involvement both above and below the diaphragm and diffuse lymphomatous lesions in the stomach and in the colon. After chemotherapy (CVP and CHOP), the thoraco-abdominal CT showed only some mesenteric lymph nodes at the upper limits of normal size; gastric and colic endoscopic patterns were normal. EUS showed regression of the polypi-like folds and near-normal thickness of rectal mucosa. However, adenopathies, though smaller, were still visible in the perirectal fat. Four months later the patient, whose general condition was good, reported some mucous bloody discharge. Endorectal ultrasonography detected an important recurrence. The mucosa was very thick, markedly hypoechoic, again raised into giant folds; a great number of enlarged lymph nodes were visible in the perirectal fat. Endoscopic biopsies showed persistence of lymphoma. High-dose chemotherapy was therefore started following Gerhartz’s schedule. After every therapeutic cycle EUS demonstrated continuous reduction in thickness of the rectal mucosa until normalization at the end of the treatment. To date, 2 years after the diagnosis, endosonographic follow-up shows a normal rectal wall (Figure 2). The whole staging is also normal. Our report demonstrates that EUS can be an excellent 882