Three-dimensional reconstruction of perineural invasion in carcinoma of the extrahepatic bile ducts

Clinical pathology of perineural invasion in hilar cholangiocarcinoma

AIM: To elucidate the characteristics and mechanism of perineural invasion in hilar cholangiocarcinoma.

METHODS: A clinicopathologic study was conducted on tissue sections from 73 patients with hilar cholangiocarcinoma to observe the incidence and modes of perineural invasion. Clinicopathologic factors, such as tumor differentiation and pathologic stage, were analyzed when perineural invasion was observed in the sections. Immunohistochemical staining for CD34 and D2-40 in cancer tissue samples was performed to clarify the association of perineural invasion with vessels.

RESULTS: The overall incidence of perineural invasion was 91.78% (67 of 73 patients). However, the incidence of perineural invasion did not show any remarkable difference in various differentiated adenocarcinomas. Logistic regression analysis identified that penetration of bile duct was significantly correlated with perineural invasion (P < 0.01). The microvessel density (MVD) was significantly lower in well-differentiated adenocarcinomas than in moderately- and poorly- differentiated adenocarcinomas (P < 0.05). Five patterns were observed as the tumor cells invaded nerve fibers. Although tumor cells were found to invade microvessels and microlymphatics, immunohistochemical staining for CD34 and D2-40 respectively showed no association between perineural invasion and lymphatic or vascular invasion.

CONCLUSION: Perineural invasion is common in hilar cholangiocarcinoma and does not develop via the lymphatic or vascular network, but is a continuous extension from the primary tumor. Nerve plexus around the membrana adventitia should be completely divested during radical excision of hilar cholangiocarcinoma.