Sessile Serrated Adenoma (SSA) and Borderline Sessile Serrated Adenoma (BSSA) Differ from Hyperplastic Polyp (HP) and Normal Colorectal Mucosa by the Status of Endocrine Cells
Mahin Mohammadi, Amna Aziz, Michael Bzorek, Susanne Holck. Hvidovre University Hospital, Hvidovre, Denmark; Hospital South, Naestved, Denmark
Background: Dilatation and serration of cryptbases are important qualities of sessile serrated adenoma (SSA) and, to a lesser extent of its borderline variant (BSSA) . We have previously reported additional qualities of BSSA, more in line with SSA than with hyperplastic polyps (HP), including proneness of large polyp size and demographic data . A single communication  on SSAs has further noticed an absence of endocrine cells in SSA, a property not subsequently validated. Nor has this feature been addressed in relation to BSSA. Here, these serrated polyps are systematically examined for chromogranin A-positive cells, correlating the results with those of HP.
Design: The material, previously detailed , comprised 24 SSAs, 13 BSSAs, and 11 HPs matched for site and age as well as 10 biopsies of normal colorectum. The specimens were immunostained for the endocrine marker chromogranin A. The immunostained slides were scrutinized for the presence of labelled cells, the number of which was counted in 10 crypts per specimen (mode of selection: for SSA and BSSA structurally aberrant crypts were chosen, for HP and normal mucosa 10 contiguous, longitudinally or near longitudinally cut crypts were chosen).
Results: Immunopositive cells (any number) were recorded in 25%, 38%, 100%, and 100% of the studied SSAs, BSSAs, HPs, and normal mucosa, respectively. Among specimens with immunopositive cells, the average number per counted crypt was 0.12, 0.26, 2.34, and 2.45 for SSAs, BSSAs, HPs, and normal mucosa, respectively.
Conclusions: We have previously demonstrated that BSSA in several, albeit not all respects, resembles SSA more so than HP. Here we add the endocrine cell status to this notion, which may be exploited in the routine diagnostic process and which strengthens the idea that HP fundamentally differs from SSA and BSSA.
Ref.: 1. Mohammadi et al. Pathol Res Pract 2011; 207: 410-16; 2. Mohammadi et al. J Clin Pathol, 2012; 3. Torlakovic et al. Am J Surg Pathol 2003; 27: 65-81.
Tuesday, March 5, 2013 1:00 PM
Poster Session IV # 133, Tuesday Afternoon