Center for Colorectal Cancer, Research Institute and Hospital, National Cancer Center, Goyang, Gyeonggi, Korea.
Endoscopy. 2011 Feb;43(2):100-7. doi: 10.1055/s-0030-1256027. Epub 2010 Dec 16.
Laterally spreading tumors (LST) are classified into two subtypes, with the nongranular type harboring a higher risk of (pre)malignant changes than the granular type. Further subdifferentiation into two subgroups each has been suggested, but the clinical significance of such a subdifferentiation has not previously been studied in detail in larger numbers.
Out of 6499 patients diagnosed with colorectal adenomas between January 2006 and November 2008, 153 patients (2.35 %) had 158 LSTs, 96 with a granular and 62 with a nongranular pattern. The former group was subdivided into homogeneous and nodular mixed, the latter group into flat elevated and pseudodepressed. Clinical and histopathological parameters were compared among the four subtypes.
Parameters were variably distributed between the four groups, with nodular mixed tumors being larger than the other three types ( P < 0.0001). As in other studies, malignant transformation and premalignant lesion (HGIN/CIS) were more frequent in nodular mixed than in homogeneous tumors (45.0 % vs. 5.6 %, P < 0.001), and also more common in pseudodepressed than in flat elevated tumors (41.7 % vs. 13.2 %, P = 0.011). Submucosal invasive cancer was present in 8.3 % of nodular mixed tumors, 7.9 % of flat elevated, and 12.5 % of pseudodepressed, while it was absent in homogeneous tumors. Serrated adenoma was identified in 10.8 % of all LSTs, and sessile serrated adenoma tended to be more common in flat elevated tumors.
Further subdifferentiation of the LST lesions to identify lesions at risk of malignant transformation makes most sense in the granular type. Among nongranular LSTs, both subtypes carry a significant risk.
侧向伸展性肿瘤（LST）分为两种亚型，其中非颗粒型比颗粒型更易发生（前）恶性变化。进一步细分每一种亚型为两个亚组，但这种细分的临床意义在之前的研究中尚未在更大数量的患者中进行详细研究。
在 2006 年 1 月至 2008 年 11 月期间诊断出的 6499 例结直肠腺瘤患者中，有 153 例（2.35%）患有 158 例 LST，其中 96 例为颗粒型，62 例为非颗粒型。前者进一步分为均质型和结节混合型，后者分为扁平隆起型和假凹陷型。比较了这四种亚型之间的临床和组织病理学参数。
参数在四组之间分布不均，结节混合性肿瘤大于其他三种类型（P < 0.0001）。与其他研究一样，结节混合性肿瘤中的恶性转化和前恶性病变（HGIN/CIS）比均质型肿瘤更为常见（45.0%比 5.6%，P < 0.001），而假凹陷型肿瘤比扁平隆起型肿瘤更为常见（41.7%比 13.2%，P = 0.011）。结节混合性肿瘤中有 8.3%存在黏膜下浸润性癌，扁平隆起型肿瘤中有 7.9%，假凹陷型肿瘤中有 12.5%，而均质型肿瘤中则没有。所有 LST 中均发现有锯齿状腺瘤，占 10.8%，而无蒂锯齿状腺瘤则更常见于扁平隆起型肿瘤。
在颗粒型 LST 中，进一步细分病变以识别恶性转化风险的病变最有意义。在非颗粒型 LST 中，两种亚型都有很大的风险。
