Traumatic pseudoaneurysm: a possible early lesion in the spectrum of epithelioid hemangioma/angiolymphoid hyperplasia with eosinophilia.

We describe a vascular lesion that develops secondary to trauma (pseudotraumatic aneurysm) and study its relation to epithelioid hemangioma (EH)/angiolymphoid hyperplasia with eosinophilia (ALHE). Four lesions are described, all with a distinct history of trauma to the site from which they arose. They presented with masses in the subcutaneous tissue of the head. They were studied by immunohistochemical methods to identify their component cells. The lesions all demonstrated marked thickening of the wall of small and medium-sized arteries, with capillary vascular proliferations. One lesion demonstrated increased eosinophils. Myxoid changes were noted in all lesions. We hypothesize that these lesions may represent an early form of EH/ALHE.