A Gray Patient.

Case Presentation

A 46-year-old Caucasian woman presented with a 10-year history of an asymptomatic progressive darkening of the skin. There was no previous history of inflammation, and she denied the use of medications. Examination revealed symmetric blue-gray patches involving the face, trunk (Figure 1, A and B) and extremities. Dermoscopy showed a diffuse reticulated-homogenous brown-gray pigmentation (Figure 1C). Skin biopsy revealed multiple spindle-shaped dendritic melanocytes in the dermis (Figure 1D) and immunohistochemical staining was positive for Melan-A and HMB-45.

Figure 1

(A) and (B) Remarkable blue-gray pigmentation on the trunk. (C) Dermoscopy (10x) revealing a diffuse reticulated-homogenous brown-gray pigmentation. (D) Histopathology showing multiple spindle-shaped dendritic melanocytes in the dermis (arrows).

Teaching Point

Acquired dermal melanocytosis is a rare pigmentary disorder and its etiology remains unknown. Three theories may explain this disorder: migration of epidermal melanocytes to the dermis; migration of hair bulb melanocytes; or reactivation of pre-existing latent dermal melanocytes triggered by local inflammation or an unknown stimulus [1,2]. Melanin-containing dendritic melanocytes can be seen in the upper-middle portions of the dermis and, with the Tyndall effect, they result in a brown to bluish-gray skin pigmentation [2].