Diffuse dermal angiomatosis (DDA) is a benign and rare acquired, cutaneous, reactive, vascular disorder. We report a rare case of a 43-year-old man who presented with a large (15-cm diameter), indurated, hyperpigmented plaque covering the left buttock for 6 years. This report further discusses DDA with a review of the literature, including its classification, epidemiology, pathophysiology, etiology, histopathology, differential diagnosis, and current therapeutic approaches.