[Adenomatous tissue in colorectal carcinomas: clinical significance and probable histogenetic implications of morphological differences].

In this study we tested the hypothesis that colorectal cancers containing adenoma (CCA) could be a different entity from colon cancers without adenoma (CSA). Clinical data, histologic preparations of operative specimens and survival of 210 patients who underwent resective surgery for colorectal cancer were studied. Adenomatous tissue within the cancer was found in 62 of 210 carcinomas (CCA), the other 148 cancers were lacking adenomatous features (CSA). CCA occurred more frequently in female patients (p = 0.003). Synchronous adenomas were detected in the resected colon of 19 out 62 CCA and of 24 out 148 CSA (p = 0.04). CCA showed the extent of intraparietal spread (p = 0.001), grade (p = 0.007) and stage (p = 0.004) lower than CSA. These characteristics also appeared statistically related to size of the cancers. The adenomatous tissue within CCA was tubular in 4 cases, tubulo-villous in 34 and villous in 24 cases. The villous histotype was statistically related to the older age of patients (p < 0.0001), larger cancer size (p = 0.01), presence of synchronous adenomas in the resected colon (p = 0.02) and higher histologic grade of the cancer (p < 0.05). Patients with CCA evidenced a higher 5-year survival rate (p = 0.02). Our results evidence epidemiologic, clinical and pathologic differences between CCA and CSA and suggest a possible double histogenesis of colon cancer.