Presence of a distinct neural component in congenital vascular malformations relates to the histological type and location of the lesion.

Congruency of the development of peripheral nerves and blood vessels has been well described, and usually, the nerves and blood vessels follow each other during development. Although little is known about the existence of a substantial neural component in vascular malformations, we investigate the presence of an intralesional component of nerve bundles in congenital vascular malformations of soft tissues. Resection specimens of 130 congenital vascular malformations of soft tissue were retrospectively screened for the presence and extent of intralesional mature nerves bundles. Lesions were histologically categorized in arteriovenous malformations (n = 83), pure venous malformations (n = 33), and lymphatic-venous malformations (n = 14). For identification of nerves, all sections were immunostained with anti-S100. GLUT-1 immunostaining excluded the presence of infantile hemangiomas in these series. Of 130 cases, 96 (74%) showed a substantial increase of intralesional nerves in close apposition to the vessels. The nervous component appeared to be more extensive in the head and neck region and upper extremities than in malformations of other topographic sites. Most cases of arteriovenous malformations showed an increase in nerve elements (87% of all arteriovenous malformations), which was more than in pure venous malformations (55%). In cases of lymphatic-venous malformations, the areas composed of lymphatic vessels showed an almost complete absence of nerves. Prior surgery in the malformation gave no different nerve pattern compared to cases that were surgically treated for the first time. The abundant presence of intralesional mature nerves in most congenital vascular malformations suggests that at least in a large subset of lesions, neural components are an integral part of the developmental disorder. This is particularly evident in the arteriovenous type of malformations and lesions that arise in the head and neck region of the body.