The Role of Crush Cytology in the Diagnosis of Large-Intestine Lesions with Correlation on Histopathology

Objective: To study the efficacy of colonoscopic crush cytology as a convenient and near-accurate method to evaluate colonic neoplasms. Study Design: Retrospective and cross-sectional. The original cytologic diagnoses were correlated with a histology report on 100 cases sent to the cytology laboratory over 2 years. Results: Of the 100 cases, 25 were nonmalignant. Of the 75 malignant lesions, 72 could be identified as positive for malignancy on cytology. The false-positives consisted of 6 adenomas and 1 case of ulcerative colitis. Thus, sensitivity and specificity of cytology are 96 and 63.2%, respectively. Of the 6 adenomas diagnosed as malignant, 4 showed high-grade dysplasia, and the other 2 showed superficial ulceration with low-grade dysplasia on histopathology. The ulcerative colitis case showed widespread ulcers and regenerative/reparative features on biopsy. The 3 adenocarcinomas diagnosed s benign on cytology showed an occasional malignant cell with thickened nuclear borders and prominent central nucleoli. Conclusions: With careful attention to the cytomorphology, coupled with good clinical and endoscopic correlation, crush cytology of the large intestine is a reliable diagnostic tool. It categorizes lesions as malignant and benign with a high sensitivity, positive predictive value, and negative predictive value. Adenomas and reparative/regenerative changes seen in inflammatory bowel disease are major pitfalls in the cytology diagnosis of malignancy that may be averted by informing the endoscopic findings and clinical history. Cytology diagnosis saves time and gives proper feedback to the gastroenterologist.