Primary colorectal lymphoma: computed tomography and double-contrast barium enema examination findings with histopathological correlation in 19 patients

Background: Primary colorectal lymphoma (PCL) is a rare disorder, the accurate imaging diagnosis of which remains a clinical challenge. This study aimed to characterize the imaging features of PCL by double-contrast barium enema (DCBE) examination and computed tomography (CT) and correlate them with histopathological findings. Methods: DCBE (n=6) and CT (n=19) findings for 19 pathologically proven PCLs were evaluated and compared with histopathological findings in this retrospective analysis. Results: Non-Hodgkin lymphoma was present in all patients, and the most common histological type was diffuse large B-cell lymphoma (63.2%, 12/19). The most common site was the ileocecum (84.2%, 16/19). CT revealed circumferential infiltrative lesions (68.4%, 13/19), polypoid masses (26.3%, 5/19) and ulcerative lesions (5.3%, 1/19). Most (94.7%, 18/19) lesions appeared as moderate enhancements. Fourteen (73.7%, 14/19) patients had serous membrane infiltration presenting as a poorly defined serous membrane and focal opacities in the pericolonic fat. Regional lymph node involvement was observed in twelve (63.2%, 12/19) patients who presented with aggregated nodules or masses. Frequent findings of the DCBE exam included a filling defect and niche with slight mucosal destruction, mild luminal narrowing and preserved peristalsis. The imaging appearance reflected the gross pathological findings well, although the preoperative diagnostic accuracy was low. Conclusions: The imaging features of PCL have a relatively characteristic appearance but are still, at times, hardly differentiated from carcinoma. Familiarity with the radiological features of PCL on DCBE and CT can help ensure a correct diagnosis.