Four cases of capillary aneurysm - Clinical differential diagnosis with malignant melanoma

Capillary aneurysm is classically described as a suddenly growing dark papule, and is also known as thrombosed capillary or vein. It is clinically significant that the clinical features of capillary aneurysm are closely similar to those of malignant melanoma or dyspiastk nevus. The histopathological finding of capillary aneurysm reveals dilated thin-walled venule(s) just beneath the hyperplastic epidermis, lined by a single layer of endothelium and a thrombus in the lumen. This abstract focuses on four patients who presented with a dark black-colored dome-shaped nodule and clinical impression included malignant melanoma, dysplastic nevus, angiokeratoma and lymphangioma circumscriptum. We herein report four cases histologically diagnosed as capillary aneurysm, which should be considered for differential diagnosis.