Cutaneous epithelioid angiomatous nodule arising in capillary malformation

Cutaneous epithelioid angiomatous nodule (CEAN) represents a rare, benign vascular lesion described by Brenn and Fletcher in 2004. To the best of our knowledge, the development of CEAN in a pre-existing vascular malformation has not been previously reported. A 52-year-old Japanese woman presented with multiple erythematous papules developed on violaceous macule of the right back that had been diagnosed as capillary malformation (CM) in childhood. Histopathological examination of one erythematous papule revealed a relatively well-circumscribed nodule composed mostly of epithelioid cells in the dermis. Abnormal dilated vessels were also identified around the lesion in the dermis, suggesting a CM. Immunohistochemically, the epithelioid cells were positive for CD31 and CD34. Staining for α-smooth muscle actin highlighted pericytes with epithelioid features. These findings were consistent with a diagnosis of CEAN arising in CM. The excised specimens of other erythematous papules revealed pyogenic granuloma (PyG) with focal epithelioid morphology accompanied by CM. We present the first reported case of CEAN arising in CM. Considering the histopathological findings, we speculate that CEAN of our case could be associated with PyG developed in pre-existing CM, and may thus be a variant of PyG with a mostly epithelioid appearance.