An immunohistochemical study of angiokeratomas of children.

ABSTRACT

BACKGROUND: Angiokeratomas are vascular anomalies in which the clinical, histological, and immunohistochemical characteristics are insufficient to determine whether the lesion is a vascular neoplasm or vascular malformation, and their exact origin is also uncertain. To further clarify the nosology of angiokeratomas, we studied 14 cases. OBJECTIVE: To analyze immunohistochemical characteristics of angiokeratomas to gain further insight into its histogenesis. METHODS: We carried out a retrospective review of the histopathology files. Immunohistochemical expression for Wilms tumor 1 (WT1), GLUT1, D2-40, podoplanin, Prox1, and ERG1 was performed in 14 cases. RESULTS: None of the lesions showed cytoplasmic immunoreactivity for WT1. GLUT1 resulted to be negative in 13 cases. All 14 cases in our series showed some expression with at least 1 lymphatic marker. In 12 cases, the positivity was diffuse and strong for ERG1. CONCLUSIONS: Angiokeratomas are complex lesions with difficult classification. Angiokeratomas are best considered vascular malformations in children, according to the WT1-negative stain. The lymphatic component of angiokeratoma is demonstrated by positivity and/or focal expression for lymphatic markers (podoplanin and Prox1); however, a blood capillary component within the malformation cannot be excluded.