Sessile serrated lesion and its borderline variant - Variables with impact on recorded data

Sessile serrated lesion (SSL), belonging to non-dysplastic serrated polyps (SP), has lately received much focus. Its role in the serrated neoplasia pathway(s) seems well established. Data on prevalence rate, demography, and some polyp characteristics remain, however, to be firmly established. Nor has its relation to SPs with subtle aberrant features, falling short of definite SSL-histology, been sufficiently addressed. The aim of this study was to highlight variables that may influence recorded data on SSL and to further discuss the appropriate place of SPs that possess histological attributes intermediate between traditional hyperplastic polyp (HP) and SSL, termed borderline SSL (BSSL). Upon review of 8.324 consecutive colorectal polyps signed-out as HP, 219 SSLs and 206 BSSLs were segregated, using strict predetermined criteria. Predominant left-sidedness and equal gender distribution characterized the present series, though right-sided SSLs occurred significantly more often in older subjects with a trend toward more females. The lower age of patients with SSL/BSSL in the last part of the study reflects the increased focus on hereditary neoplasm. BSSL differed from SSL only by a smaller polyp size. Discordant SSL-data can be ascribed primarily to diversities in endoscopic procedure, though tissue handling, the criteria used, and study design may contribute. A precursor status of BSSL to SSL is an attractive, though still unsubstantiated thesis.