Calcinosis Cutis, Calcinosis Circumscripta, and “Mille Feuille” Lesions

Skin and subcutaneous lesions of 2 cases with natural occurring Cushing’s disease and 1 case with calcinosis circumscripta were compared. Case 1 was typical of osteoma cutis, containing somewhat regularly arranged discrete ossification foci in the mid and deep dermis. Case 2 had layers of “mille feuille”, yellowish to white gritty chalky substances diffusely scattered in the subcutis, seen histologically as disseminatedly scattered light purple crystalloid and blue granular mineral salts. Lesions stained orange red with Alizarin Red S indicated the presence of calcium ions. Discrete ossification foci in the deep dermis and early multifocal collagenolysis with mineralization were also noted. Case 3 was typical of calcinosis circumscripta, seen grossly as yellowish chalky substance in both dermis and subcutis, and histologically as lakes of wellcircumscribed light purple crystals and granular deep blue mineral salts. Case 2 had features of calcinosis cutis such as ossification foci and early multifocal collagenolysis. Case 2 also had “mille feuille” that was histologically similar to those mineral salts in case 3, but was not circumscribed, and was not exactly calcinosis universalis. The component in case 1 was most likely hydroxyapatite Ca10(PO4)6(OH)2; the “mille feuille” of case 2 was most likely “calcium soap” after panniculitis and fat necrosis; and that in case 3 was most likely calcium phosphate CaPO4. Local factors, such as fluid exudation reflecting how well the inflammation was controlled clinically, may influence the wound healing, and thus the outcome of lesions.