The prognostic significance of epithelioid granulomas in Crohn's disease (CD) remains controversial. We have determined the prognostic significance of epithelioid granulomas noted in endoscopic rectosigmoid biopsies obtained from untreated pediatric patients at initial presentation of CD. Data collected from 19 subjects with rectosigmoid granulomas and inflammation (Group 1) were compared to those obtained from another 37 subjects (Group 2) with CD of the rectosigmoid, but in whom no granulomas were present. Both groups had similar ages at disease onset [Group 1: 11.6 +/- 3.6; Group 2: 10.4 +/- 4.0 years (X +/- SD)]. At diagnosis, Group 1 had more extensive CD (small bowel and colon involvement, with Group 1 74% versus Group 2 30%; isolated rectosigmoid involvement, with Group 1 11% versus Group 2 35%; p less than 0.01). Perianal disease was also more common in Group 1 (58% versus 27% Group 2; p less than 0.05). However, CD activity scores and clinical laboratory findings were comparable. Duration of follow-up was identical (5.6 +/- 3.3 years) for both groups. By the end of the period of follow-up, 43% of Group 2 had developed small bowel involvement, but Group 1 continued to have more extensive CD (p less than 0.05). Perianal fistulae and abscesses and anal stenosis were more frequent in Group 1. Throughout this period, the need for oral and parenteral corticosteroids, 6-mercaptopurine, and nutritional support modalities were similar in the two groups. Although the number of subjects requiring hospitalization and the number of hospitalizations per patient were similar in both groups, Group 1 had more surgery (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)