Histopathologic Findings of Cutaneous Hyperpigmentation in Addison Disease and Immunostain of the Melanocytic Population.

The histopathological features of cutaneous hyperpigmentation in Addison disease have very occasionally been reported, and they include acanthosis, hyperkeratosis, focal parakeratosis, spongiosis, superficial perivascular lymphocytic infiltrate, basal melanin hyperpigmentation, and superficial dermal melanophages. We present a study on 2 biopsies from the arm and the thigh in a 77-year-old woman with a long clinical history of Addison disease as well as senile purpura and alopecia of female pattern. The patient presented diffuse hyperpigmentation of the skin, more pronounced on her face, and left upper forehead. The skin biopsies showed no remarkable dermal inflammatory infiltrate with melanocytic hyperpigmentation of the basal layer of the epidermis as well as a mild amount of melanophages in the papillary dermis. In addition, we found lipofuscin in the luminal pole of the secretory epithelium of the eccrine glands. In the perieccrine areas, there was Perls-positive pigment in the cytoplasm of macrophages most likely related to the senile purpura. An immunohistochemical study with Melan-A showed a melanocyte/keratinocyte ratio of 1:20 (5%) in the arm and of less than 1:50 (only 2 melanocytes in the whole section; <2%) in the thigh.