N Kalimuthu Sangeetha, Serra Stefano, Hafezi-Bakhtiari Sara, Colling Richard, Wang Lai Mun, Chetty Runjan
Department of Pathology, Laboratory Medicine Program, University Health Network, University of Toronto, Toronto, ON, Canada.
Department of Cellular Pathology, Oxford University Hospitals, Oxford, UK.
Histopathology. 2017 Aug;71(2):208-216. doi: 10.1111/his.13212. Epub 2017 May 5.
Traditional serrated adenomas (TSAs) account for 5% of serrated polyps, and have a villiform architecture, eosinophilic cells with a brush border, and indented, flat-topped luminal serrations. However, some are composed of mucin-filled goblet cells (GCs): mucin-rich TSA (MrTSA). The aim of this study was to determine whether this variant has unique features as compared with classic TSA (cTSA).
One hundred and fifty-six TSAs were retrieved from the period 2010-2016. Patient demographics, site of polyps and 16 microscopic variables were evaluated. TSAs containing ≥50% GCs were classified as MrTSAs. Ectopic crypt foci (ECFs) were quantified as low (1-10) or high (>10), counted at ×200 magnification, and the average was taken for 10 fields. Twenty-four fulfilled the criteria for MrTSA. In males, MrTSAs (65%) were more prevalent than cTSAs (55%). There was no age difference, and both variants had a predilection for the left colon, although, in the right colon, MrTSAs were more frequent (39%) than cTSAs (10%) (P = 0.012). Adenomatous dysplasia was present in four of 24 MrTSAs (low grade, 3; high grade, 1). The most distinctive features of MrTSAs were: a variable growth pattern [endophytic (9%), mixed (30%), or villiform/exophytic (61%)], and a lower frequency of ECFs (P = 0.001) and more intraepithelial lymphocytes (P < 0.05) than in cTSAs. MrTSAs retain characteristic luminal serrations, at least focally. Inflamed MrTSAs can mimic inflammatory polyps and hamartomatous polyps (when there are >95% GCs).
MrTSA is characterized by >50% GCs, and fewer ECFs than cTSA, but with preservation of archetypal luminal serrations. Awareness of this variant will prevent misdiagnosis, given the association of TSA with the accelerated pathway to colorectal cancer.
传统锯齿状腺瘤（TSA）占锯齿状息肉的5%，具有绒毛状结构、带有刷状缘的嗜酸性细胞以及凹陷的、平顶的管腔锯齿。然而，有些是由充满黏液的杯状细胞（GC）组成：富含黏液的TSA（MrTSA）。本研究的目的是确定与经典TSA（cTSA）相比，这种变体是否具有独特特征。
检索2010 - 2016年期间的156例TSA。评估患者人口统计学资料、息肉部位以及16个微观变量。含有≥50% GC的TSA被归类为MrTSA。异位隐窝灶（ECF）在×200倍放大倍数下计数并量化为低（1 - 10个）或高（>10个），取10个视野的平均值。24例符合MrTSA标准。在男性中，MrTSA（65%）比cTSA（55%）更常见。年龄无差异，两种变体都好发于左半结肠，不过在右半结肠，MrTSA（39%）比cTSA（10%）更常见（P = 0.012）。24例MrTSA中有4例存在腺瘤性发育异常（低级别，3例；高级别，1例）。MrTSA最显著的特征是：生长模式多样[内生性（9%）、混合型（30%）或绒毛状/外生性（61%）]，与cTSA相比，ECF频率较低（P = 0.001）且上皮内淋巴细胞较多（P < 0.05）。MrTSA至少在局部保留了特征性的管腔锯齿。炎症性MrTSA可类似炎性息肉和错构瘤性息肉（当GC>95%时）。
MrTSA的特征是GC>50%，且ECF比cTSA少，但保留了典型的管腔锯齿。鉴于TSA与结直肠癌的加速发展途径相关，认识到这种变体将有助于防止误诊。
