PT  - JOURNAL ARTICLE
AU  - Xianyong Gui
AU  - Martin Köbel
AU  - Jose GP Ferraz
AU  - Marietta Iacucci
AU  - Subrata Ghosh
AU  - Shuhong Liu
AU  - Young Ou
AU  - Marco Perizzolo
AU  - Robert J Winkfein
AU  - Peter Rambau
AU  - Douglas J Demetrick
TI  - Histological and molecular diversity and heterogeneity of precancerous lesions associated with inflammatory bowel diseases
AID  - 10.1136/jclinpath-2019-206247
DP  - 2020 Jul 01
TA  - Journal of Clinical Pathology
PG  - 391--402
VI  - 73
IP  - 7
4099  - http://jcp.bmj.com/content/73/7/391.short
4100  - http://jcp.bmj.com/content/73/7/391.full
SO  - J Clin Pathol2020 Jul 01; 73
AB  - Aims Inflammatory bowel disease (IBD)-associated precancerous lesions may be adenomatous or non-adenomatous with various histomorphologies. We aim to validate the newly proposed classification, to explore the neoplastic nature of the non-adenomatous lesions and to elucidate the molecular mechanisms underlying the different histomorphologies.Methods 44 background precursor lesions identified in 53 cases of surgically resected IBD-associated colorectal and ileal carcinomas were reviewed for the histomorphological features (classified into adenomatous, mucinous, sessile serrated adenoma (SSA)-like, traditional serrated adenoma-like, differentiated, eosinophilic and serrated not otherwise specified (NOS)) and analysed for a key panel of colonic cancer-related molecular markers.Results Approximately 60% of the lesions were adenomatous, of which some had mixed serrated, mucinous or eosinophilic changes. The remaining non-adenomatous lesions, including all other types except SSA-like type, mostly showed mixed features and focal adenomatous dysplasia. KRAS mutation and p53 mutant-type expression were found in about half cases across all types, while PIK3CA mutation only in some of adenomatous and eosinophilic lesions and MLH1/PMS2 loss in a subset of adenomatous, mucinous and eosinophilic but not in differentiated and serrated lesions. SAT-B2 or PTEN loss and IMP3 overexpression were seen in a small subset of lesions. No BRAF, NRAS or EGFR gene mutation was detected in any type. Certain molecular-morphological correlations were demonstrated; however, no single or combined molecular alteration(s) was specific to any particular morphological type.Conclusions IBD-associated precancerous lesions are heterogeneous both histologically and molecularly. True colitis-associated adenomatous lesions are unlikely conventional adenomas. Non-adenomatous lesions without frank cytologic dysplasia should also be regarded as neoplastic.