Background  Porokeratosis is a rare disorder of keratinization with both autosomal dominant and acquired forms. Immunosuppression has been associated with the development of porokeratosis in numerous case reports and series. To our knowledge, however, only five cases of porokeratosis have been reported following bone marrow transplantation.

Results  We report five cases of porokeratosis of Mibelli following bone marrow transplantation. The diagnosis of porokeratosis was made between 1 and 13 years post-transplantation. The underlying malignancy in four of the five cases was leukemia, while the fifth patient had non-Hodgkin's lymphoma. Porokeratosis developed during remission in the four leukemia patients, whereas, in the fifth patient, it occurred during a relapse of lymphoma.

Conclusions  Porokeratosis may develop following bone marrow transplantation. Our five cases double the number reported in the medical literature, and the incidence of porokeratosis following bone marrow transplantation may be significantly higher than previously recognized. As cutaneous carcinomas have been reported in association with porokeratosis, careful surveillance for porokeratosis in bone marrow transplant recipients is warranted.