Metastatic carcinoma simulating inflammatory colitis.

Metastatic carcinoma to the colon may be mistaken for inflammatory colitis, particulary Crohn's disease, both clinically and roentgenologically. Characteristic changes include mucosal thickening, nodular masses, multiple and eccentric strictures, asymmetric involvement, pseudosacculations, and spiculations of contour. This report, based upon experience with 12 cases, establishes the distinctive roentgen features of metastatic disease to the colon from a variety of primary sites. It is shown that these changes are dependent upon pathways of spread, growth characteristics, and local tissue response. The clinical importance of making this differential diagnosis is two-fold. A patient with an occult or a known primary malignancy may present clinically with metastatic disease to the colon masquerading as inflammatory colitis. Recognition of the characteristic roentgenologic changes immediately either leads to a search for the primary neoplasm or establishes the diagnosis of widespread disease.