A case with pachyonychia congenita and B-cell lymphoma.

Pachyonychia congenital (PC) is a rare autosomal dominant genodermatosis characterized hyperkeratosis affecting the nails and palmoplantar areas, oral leukokeratosis, and cystic lesions. A 39-year-old woman with PC type 1 (Jadassohn-Lewandowsky syndrome) and B-cell lymphoma is described. No similar disorders or parental consanguinity were found in her family. Typical features of PC developed since her early childhood and the diagnosis of B-cell lymphoma was established seven years ago, without a clear causal relation between these entities. Despite inherent limitations of a single case, this report may contribute to PC understanding.