Colorectal cytology in chronic ulcerative colitis.

During a period of ten years, 109 colorectal cytology specimens were obtained from 41 patients with chronic ulcerative colitis. There were 28 male and 13 female patients, whose average age was 45 years. All patients were symptomatic and had ulcerative colitis with repeated attacks of profuse diarrhea on the average for 12 years prior to their first cytologic examination. Eight cytology specimens were positive for malignant cells, 35 had atypia, 58 were negative and 8 were unsatisfactory. The malignant cells showed marked anisocytosis, pleomorphism and nuclear hyperchromasia and appeared in loosely cohesive clusters or in single forms in an inflammatory and necrotic background. Subsequent colectomy revealed invasive carcinoma in five patients and carcinoma in situ in two. Smears that were negative or showed atypia contained abundant chronic inflammatory cells. The atypical colonic epithelial cells contained prominent nuclei and formed cohesive clusters. Surgical biopsy and/or segmental resection revealed the presence of polyps, pseudopolyps, polypoid hyperplasia, mucosal atypia and crypt abscesses in patients with atypical and negative cytologic findings. It is concluded that cytologic examination of the colon can play an important role in the examination of patients with ulcerative colitis and allows for the detection of malignant transformation of the colonic mucosa.