A case of pachyonychia congenita with oral leukoplakia and steatocystoma multiplex.

Pachyonchia congenita (PC) is an uncommon autosomal dominant genodermatosis affecting the nails and other ectodermal tissues. The most striking features are symmetrically thickened dysmorphic nails and hyperkeratotic skin lesions. We report a case of pachyonychia congenita in a 30-year-old male patient who had thickening and gray-brown discoloration of all nails and many nodules on his back and neck. He also had hyperkeratotic skin lesions on both feet. His tongue had irregularly-shaped, whitish plaques. Histology of these nodules revealed the characteristic features of steatocystoma multiplex. After treatment with oral retinoic acid, his hyperkeratotic skin lesions improved.