Endoscopic Biopsy in Differential Diagnosis of Colorectal Serrated Lesions

Abstract

Background. Preoperative biopsy is recommended for morphological verification of colorectal epithelial neoplasms prior to their endoscopic resection. However, histological reports for endoscopic biopsy and resected lesions are not reliably consistent.Aim. Assessment of sensitivity, specificity and accuracy of endoscopic biopsy in differential diagnosis of colorectal serrated adenomas and risk factors for variance between biopsy results and morphological examination of completely resected lesions.Materials and methods. The assay used data on 56 morphologically verified serrated adenomas diagnosed and resected in 50 patients (14 men, 36 women; average age 66.9 ± 10.5 years). Biopsy was taken from all tumours before endoscopic resection. Results of morphological examination of biopsy samples and resected tumours were analysed and compared. Sensitivity, specificity and accuracy of biopsy was assessed, with the tumour size and type and biopsy forceps system taken as criteria.Results. The identified cases included 22 (39.3%) right-colon, 21 (37.5%) left-colon and 13 (23.2%) rectal lesions of 28.5 ± 2.6 mm average size. Polypoid were 17 (30.3%), non-polypoid — 6 (10.7%) and spreading — 33 (59%) of the tumours. Full consistency of morphological examination was observed for 12 cases (21.4%). In 9 cases (16%), dysplasia was established as mild-graded with biopsy, whilst the eradicated tumours contained severe dysplastic foci. Foci of adenocarcinoma were detected in 10 tumours (including 2 with submucosal invasion), but only 2 cases were correctly diagnosed for malignant adenoma with biopsy. Tumour morphology was misidentified in 32 cases (57.1%).Conclusions. Preoperative forceps biopsy is shown to possess low sensitivity in differential diagnosis of serrated colorectal lesions and very low sensitivity to predict malignant serrated adenomas.

Keywords

• colonoscopy
• biopsy
• serrated adenoma
• colon
• polyp