COLORECTAL MINI-DE NOVO CARCINOMA - A REALITY IN GERMANY TOO

Background and Study Aims: Based on Japanese case studies, we examined whether colorectal mini-de novo carcinoma also occurs outside Japan. We defined mini-de novo carcinomas as carcinomas infiltrating the submucosa, with a maximum diameter of 10 mm, and with no evidence of precursive adenomatous tissue. Patients and Methods: Between 1988 and 1994, we diagnosed carcinomas of this type in polypectomy and surgical resection specimens from 155 patients, These mini-de novo carcinomas did not differ from carcinomas arising from adenomas in terms of patient age (median 67.1 years), sex distribution (men: women 0.96:1), or location-they occurred primarily in the sigmoid (53%) and rectum (27.3%). Results: Most of the mini-de novo carcinomas were macroscopically of the polypoid type (59.4%); flat, elevated carcinomas were also relatively frequent, including those with a central concave depression (21.9%) and those without a depression (12.3%), Histologically, all of the lesions without exception were adenocarcinomas (grade 1: 28.4%, grade 2: 65.8%, grade 3: 5.8%), There was carcinomatous invasion of submucosal lymphatic or blood vessels in 20%. Conclusions: Our analysis shows that colorectal mini-de novo carcinoma is not a purely Japanese phenomenon, and that these carcinomas are being diagnosed with increasing frequency as the awareness of their existence and macroscopic growth characteristics increases.