Sonography of peritoneal lymphomatosis: some new and different findings.

OBJECTIVE

The purpose of this study was to assess the sonographic features of lymphoma with peritoneal, omental, and mesenteric involvement.

MATERIALS AND

METHODS

All records of peritoneal biopsies under the guidance of ultrasound in our institutional database were retrospectively reviewed to find out cases with peritoneal, omental, and mesenteric lymphoma involvement. Sonographic studies of these patients were evaluated for the presence of peritoneal involvement, ascites, omental mass, organomegaly, retroperitoneal lymphadenopathy, and other associated findings.

RESULTS

Six cases of omental lymphoma and 3 cases of mesenteric lymphoma were included in the study. All the cases were diffuse large B-cell non-Hodgkin lymphomas. Under high-frequency insonation, the omentum became markedly irregularly thickened when involved by lymphoma, and in 4 cases, "fish scale" appearance was observed, and the fish scale was proved to be normal omental tissue by pathology. Hypoechoic mass or "sandwich" appearance of thickened mesenteric tissue could be observed in mesenteric lymphoma. The amount of ascites in omental lymphoma was much more than that in mesenteric lymphoma, and intensive echogenic particulate was found in ascites in 2 cases of omental lymphoma. Retroperitoneal lymphadenectasis was seen in only 3 cases, and the most common location was para-aortic.

CONCLUSIONS

The fish scale sign in the omentum and the sandwich sign of the mesentery might indicate the possibility of peritoneal lymphoma, and ultrasound seems to be the ideal imaging modality to show the thickened omentum and mesentery mass when lymphoma involves peritoneum.