Giant Centrifugal Miliaria Profunda

Miliaria profunda is due to duct obstruction and rupture below the epidermis, with dermal sweat leakage associated and a variable inflammatory reaction. A rare but distinct presentation of miliaria profunda in infants is named giant centrifugal miliaria profunda (GCMP), showing centrifugal expansion of large, annular plaques. On histology, GCMP shows hyperkeratosis with ortho- and parakeratosis, and acanthosis with foci of intercellular edema. Acrosyringia are distended with obstruction by eosinophilic plugs of ortho-parakeratotic material. Dermal ducts appear dilated and show squamous metaplasia. A periductal and peri-eccrine variable inflammatory infiltrate contains neutrophils and often granulomatous inflammation is identified. We report two cases of GCMP, one of them associated with an MAP2K1 germinal RASopathy.