Nodules Arising Within Port-wine Stains: A Clinicopathologic Study of 31 Cases

Nodules are seen in approximately 10%―30% patients within port-wine stains (PWS) and usually regarded as vascular "tumor." However, nodules arising within PWS have not been systematically examined and the precise pathologic characteristics of them are unknown. The aim of this study is to evaluate the clinicopathologic and immunohistochemical features of blood vessels of nodules in 31 cases. A total of 31 biopsy specimens (excision) were obtained from the representative areas of lesion of each patient with nodules. Clinical features of all patients were recorded. Hematoxylin and eosin staining, immunohistochemical staining, and Weigert elastic stain were performed to investigate the histopathologic features of nodules. In a total of 31 subjects, there are 16 patients whose nodules occurred in the area innervated by the second branch of the trigeminal nerve (51.6%), 4 in the first branch (12.9%), 6 in the third branch (19.4%), 2 in both the first, and the second branch (6.5%). Based upon specular microscopic findings, 14 biopsy specimens were designated as pyogenic granuloma (PG) (45.1%), 10 as arteriovenous malformation (AVM) (32.3%), 5 as both (16.1%), and 2 cases as cavernous-like vascular ectasia (6.5%). Moreover, both AVM and PG were prone to occurring in the area innervated by the second branch of the trigeminal nerve. In summary, we believed that both AVM and PG are not rare histologic changes in PWS. Moreover, histologic findings suggest that the major portion of nodules arising within PWS can be categorized into AVM, PG, and AVH associated with PG.