Hyperplastic polyposis: semantics, biology, and endoscopy

Variant forms of hyperplastic polyps of the colorectum, the so-called sessile serrated polyp (SSP) or sessile serrated adenoma (SSA), have recently been described. These are characterised by crypts whose serrations extend all the way to the crypt base, with a widened base that may extend laterally in a ‘boot shape’. Cytological abnormalities of the sort usually required of traditional adenomas—nuclear enlargement and loss of basal orientation—are not essential to the newer SSA terminology.1–4 A tendency for pathologists to engage in descriptive and terminological splitting have the workaday endoscopist and pathologist struggling to keep up and to decide what is important. One might not care except for the presence of emerging details of associations between sessile serrated lesions and colorectal cancer (CRC).5 6 The complex categorisation of morphological subtypes and the specifics of cancer risk have been abetted by molecular pathology correlations.7 8

Complicating matters in the world of serrated neoplasia of the colorectum has been the relationship between multiple hyperplastic polyps (HPs), or ‘hyperplastic polyposis syndrome (HPS)’ and the serrated morphology/molecular signature/cancer risk story.9 Indeed, the very term hyperplastic polyposis is defined in terms of very arbitrary criteria that have never been validated and almost certainly involves a heterogeneous spectrum of conditions. However confusing the HPS story may be, most would agree that at least when the HPs of HPS are large, right sided and/or part of the SSA spectrum, they are important to endoscopists, pathologists and colorectal surgeons.

In this issue of Gut (see page 1094), members of a seven-institution Netherlands consortium conducted a retrospective review of their 1982–2008 experience with respect to demographic, endoscopic and pathological features in patients with hyperplastic polyposis.10 This …