Hong Seung-Mo, Presley Alison E, Stelow Edward B, Frierson Henry F, Moskaluk Christopher A
Department of Pathology, University of Virginia Health System, Charlottesville, VA 22908, USA.
Am J Surg Pathol. 2006 Jun;30(6):744-9. doi: 10.1097/00000478-200606000-00011.
The histologic boundaries of the extrahepatic bile ducts (EBDs) are not well defined, despite the fact that pathologic staging of carcinomas arising in these structures requires the determination of extent of tumor invasion in this area. Perhaps in part, because the smooth muscle band in the EBD wall is not well formed throughout the length of these structures, a previous definition of the outer portion of the bile duct wall included "loose, richly vascularized connective tissue, interlaced with large nerve fibers." We have experienced difficulty in the application of these criteria in staging EBD carcinomas, which requires the histologic determination of the extent of the EBD wall. To systematically study the histologic features of EBD tissue boundaries, 34 EBD specimens obtained from autopsy were analyzed with attention to the distribution of blood vessels and nerve fibers along the length of this system. The EBD specimens were divided into lower, middle, and upper portions, and the locations of blood vessels and nerve fibers were then analyzed separately at each location. We defined the fibromuscular wall as the dense concentric arrangement of collagen and smooth muscle fibers surrounding the EBD mucosa. The location of blood vessels and nerve fibers was categorized as either (1) within, (2) junctional to, or (3) outside of the fibromuscular wall. Blood vessels and nerve fibers are located predominantly outside of the fibromuscular wall and are usually surrounded by adipose tissue throughout the entire EBD, however, their distribution in this location is not consistent. Because of these histologic features, we propose that the bile duct wall is more precisely defined as occurring between the mucosa and the outermost boundary of dense fibromuscular tissue, without consideration of the presence or absence of blood vessels and nerve fibers.
尽管肝外胆管（EBDs）癌的病理分期需要确定肿瘤在该区域的浸润范围，但肝外胆管的组织学边界并未明确界定。部分原因可能是，在这些结构的全长中，EBD壁内的平滑肌带发育不完善，因此先前对胆管壁外部的定义包括“疏松、血管丰富的结缔组织，与大型神经纤维交织”。我们在将这些标准应用于EBD癌分期时遇到了困难，而这需要对EBD壁的范围进行组织学判定。为了系统地研究EBD组织边界的组织学特征，我们分析了34例尸检获得的EBD标本，重点关注该系统全长上血管和神经纤维的分布情况。将EBD标本分为下部、中部和上部，然后分别分析每个部位血管和神经纤维的位置。我们将纤维肌壁定义为围绕EBD黏膜的胶原蛋白和平滑肌纤维的致密同心排列。血管和神经纤维的位置分为以下三类：（1）在纤维肌壁内；（2）与纤维肌壁交界；（3）在纤维肌壁外。血管和神经纤维主要位于纤维肌壁外，并且在整个EBD中通常被脂肪组织包围，然而，它们在该位置的分布并不一致。由于这些组织学特征，我们建议将胆管壁更精确地定义为位于黏膜和致密纤维肌组织最外边界之间，而不考虑血管和神经纤维的有无。
