Peritoneal lymphomatosis: CT findings

Diffuse peritoneal tumor infiltration is well recognized on computed tomography (CT) and is usually associated with carcinomatosis. The purpose of this investigation was to analyze the CT findings of peritoneal spread from primary gastrointestinal lymphomas.

Abdominal CT scans in eight patients with peritoneal lymphomatosis were retrospectively reviewed. Patients were 12-75 years old (mean = 48 years); with six patients were male and two were female. Pathologic evidence of primary lymphoma was available by colonoscopic biopsy of the terminal ileum in seven cases and by gastroscopic biopsy of the stomach in one case. All patients had non-Hodgkin's lymphoma. We analyzed CT findings in view of presence or loculation of ascites, abnormal patterns of mesentery and omentum, presence of peritoneal enhancement, presence of low attenuation and location of lymph nodes, and primary gastrointestinal lymphoma.

Although ascites was present in all patients, there was no loculation. The involvement of mesentery was present in seven patients, and the stellate pattern was the common type (4/7). The involvement of omentum was present in seven patients, and the common type was omental cake (3/7). Peritoneal enhancement was present in six patients. Enlarged lymph nodes were present in six patients, mainly at the retroperitoneum and mesentery, and showed centrally low attenuation in half the patients.

Patterns of tumor involvement of mesentery, omentum, and peritoneum seen in peritoneal lymphomatosis are indistinguishable from those seen in peritoneal carcinomatosis or tuberculous peritonitis. However, ascites without any loculation or septation and diffuse distribution of enlarged lymph nodes were helpful signs of peritoneal lymphomatosis.