Clinical, histological and ultrastructural investigations of two cases of Erythema Dischromicum Perstans (EDP) are reported. EDP is a chronic pigmented lesion of the skin, and its etiology is still unknown. The reported cases showed clinical and ultrastructural differences from what already described in the literature. EDP is also difficult to differentiate from other cutaneous pigmented lesions: clinical and morphologic differences and/or similarities are therefore discussed and compared. The usefulness for a correct diagnosis of the co-existence of optical and ultrastructural lesions which are not pathognomonic per se, is also stressed.