A rare subtype of pyoderma gangrenosum disease characterized by a solitary, erythematous, ulcerated plaque, which lacks the violaceous border typically present in classic pyoderma gangrenosum, usually affecting individuals who are otherwise healthy. Histologically, the lesion presents a central layer containing neutrophilic inflamation, surrounded by a palisade of histiocytes, which are rimmed by a lymphocytic infiltrate. In comparison with the other variants of pyoderma gangrenosum, this subtype usually shows a good response to less aggressive treatments and underlying systemic disorders are less frequently associated. It is considered the most benign and uncommon clinical variant of pyoderma gangrenosum. [from
ORDO]