OBJECTIVETo study the distribution of abdominal and pelvic lymph nodes involved in non-Hodgkin lymphoma in Chinese patients.

METHODSCT images of 241 non-Hodgkin lymphoma patients with abdominal and pelvic lymph nodes involved were reviewed. Of them, 96 patients whose clinical and image data fulfilled the requirements of the analysis were included: 1. Positive abdominal and/or pelvic nodular lesion in untreated patients examined by CT (n = 74). 2. New lesions in abdominal or pelvic lymph nodes who never had any nodular lesion by previous abdominal and/or pelvic CT (n = 14). 3. Treated patients who did not have abdominal and/or pelvic CT before, showed regression of initial disease for at lease 6 months after chemotherapy and patients showing abdominal and/or pelvic nodal lesions (n = 8) were assessed. In accordance with Clinical Schema for the Lymphoid System, these patients were divided into 3 histology subtypes: indolent (IL; n = 31), aggressive (AL; n = 61) and very aggressive (VAL; n = 2) lymphoma. The remaining 2 cases were unclassified (UCL). Both abdominal and pelvic CT scans were undertaken in 46 patients, abdominal CT only in 47 patients and pelvic CT only in 3 patients. Enhanced CT with i.v. contrast was obtained in 80 patients. The anatomic sites involved were designated as retroperitoneal (i.e. paraaortic), mesenteric, abdominal (i.e. celiac, paracardiac, gastrohepatic, and hepatic hilar, etc), retrocrural, subdiaphragmatic, common iliac, internal iliac, external iliac, and inguinal nodes, respectively.

RESULTSThe lesions were located in the retroperitoneum, with an incidence of 83% for both IL and AL. These were predominantly seen superior and inferior to the renal hila, with incidences of 72.0% (18/25) in IL and 67.3% (33/49) in AL. Pelvic lymph nodes came the next, with incidences of 41.9% (126/301 sites of IL and AL), 57.5% (50/87 sites) in IL and 35.5% (76/214 sites) in AL. Mesenteric lymph nodes stood third with incidences of 37.1% (33/89 IL and AL), 43.3% (13/30) in IL and 33.9% (20/59) in AL. There was only one statistically significant evidence that the external iliac lymph nodes were much more commonly seen in IL than in AL (P < 0.05).

CONCLUSIONIn Chinese patients, retroperitoneal, iliac, and mesenteric nodes are the most commonly involved lymph nodes in NHL. The involved retroperitoneal lymph nodes are predominantly located superior and inferior to the renal hila. The anatomic distribution of abdominal and pelvic lymph nodes in NHL of Chinese patients is different from that of the western countries.