Department of Pathology, The Methodist Hospital, Weill Medical College, Cornell University, Houston, TX 77030, USA.
Ann Diagn Pathol. 2010 Dec;14(6):408-12. doi: 10.1016/j.anndiagpath.2010.05.013. Epub 2010 Sep 22.
The muscle layer in the cystic duct and common bile duct is not well defined, and it is unresolved whether it represents muscularis mucosae or muscularis propria. Smoothelin is a novel smooth muscle-specific contractile protein expressed only in fully differentiated smooth muscle cells of the muscularis propria and not in proliferative or noncontractile smooth muscle cells of the muscularis mucosae. In this study, we characterize the histologic aspects of the muscle layer in gallbladder, cystic duct, and common bile duct by evaluation of routine histologic sections and the utilization of immunohistochemistry using desmin and smoothelin. Formalin-fixed, paraffin-embedded sections of the gallbladder (15 cases), cystic duct (11 cases), and common bile duct (10 cases) were stained for smoothelin and desmin. Staining intensity was evaluated as weak or strong. The staining pattern score was evaluated as follows: 0 or negative = less than or equal to 5% positivity, +1 or focal = 6% to 10% positivity, +2 or moderate = 11% to 50% positivity, and +3 = greater than 50% muscle cells positivity. With desmin, strong and diffuse (+3) staining was observed in all gallbladder cases (15/15, 100%), highlighting one continuous muscle layer. The muscle layer was discontinuous and interrupted in all cystic duct cases and in most common bile ducts, highlighted by the desmin stain. Smoothelin intensely stained (at least +2) muscle fibers in the gallbladder in 11 (73%) of 15 cases similar to that observed with desmin staining. In contrast, common bile ducts predominantly had absent or weak and focal immunostaining (0 or +1 staining) with smoothelin (7/10, 70%), with only a few cases (3/10, 30%) having +2 staining (no cases with +3). Cystic ducts also showed absent or weak and focal immunostaining with smoothelin, with 5 (44%) of 11 cases showing 2+ immunostaining with smoothelin (no cases with 3+). Based on our findings, we conclude that, in the gallbladder wall, the muscle layer is muscularis propria and there is no muscularis mucosae present. In the cystic duct and common bile duct, only an attenuated and incomplete muscle layer of muscularis mucosae is present; because there is no muscularis propria, there probably is limited contractile function. Differentiating these anatomical muscle structures may be important for the pathologic staging of carcinoma in these organs.
胆囊、胆囊管和胆总管的肌层界限不明显，其是否代表黏膜肌层或固有肌层尚未确定。平滑肌蛋白 smoothelin 是一种新型的平滑肌特异性收缩蛋白，仅表达于固有肌层的完全分化平滑肌细胞，而不表达于黏膜肌层的增殖性或非收缩性平滑肌细胞。在这项研究中，我们通过评估常规组织学切片和使用 desmin 和 smoothelin 的免疫组织化学，对胆囊、胆囊管和胆总管的肌层组织学特征进行了描述。对 15 例胆囊、11 例胆囊管和 10 例胆总管的福尔马林固定石蜡包埋切片进行了 smoothelin 和 desmin 染色。染色强度评估为弱或强。染色模式评分如下：0 或阴性=阳性率≤5%，+1 或局灶性=阳性率 6%10%，+2 或中度=阳性率 11%50%，+3=阳性率＞50%的肌细胞。用 desmin 染色时，所有胆囊病例（15/15，100%）均显示强而弥漫的（+3）染色，突出一个连续的肌层。所有胆囊管和大多数胆总管病例的肌层均不连续且中断，desmin 染色突出显示。在 15 例胆囊病例中，11 例（73%）平滑肌蛋白 smoothelin 染色强烈（至少+2），与 desmin 染色观察到的相似。相比之下，胆总管主要表现为 smoothelin 缺失或弱而局灶性免疫染色（0 或+1 染色）（7/10，70%），只有少数病例（3/10，30%）存在+2 染色（无+3 染色）。胆囊管也存在 smoothelin 缺失或弱而局灶性免疫染色，11 例中有 5 例（44%）显示 smoothelin 为 2+免疫染色（无 3+染色）。根据我们的发现，我们得出结论，在胆囊壁中，肌层为固有肌层，不存在黏膜肌层。在胆囊管和胆总管中，仅存在薄弱且不完整的黏膜肌层固有肌层；由于没有固有肌层，可能收缩功能有限。区分这些解剖学肌肉结构对于这些器官癌的病理分期可能很重要。
