Primary cutaneous T-cell lymphoproliferative disorder of donor origin after allogeneic haematopoietic stem-cell transplantation.

A 56-year-old male patient had a history of mantle-cell lymphoma, which was treated with polychemotherapy and reduced-intensity conditioning allogeneic haematopoietic stem cell transplantation (ASCT) from his healthy sister with an identical human leucocyte antigen profile. Six years after transplantation, the patient developed asymptomatic eczema-like cutaneous lesions. Histologically the lesions contained a dense superficial lichenoid infiltrate, mainly consisting of CD4+ atypical medium to large lymphocytes showing indented hyperchromatic nuclei. In situ hybridization for Epstein-Barr virus was negative. PCR amplification of the T-cell receptor-gamma chain gene from several lesions revealed a monoclonal rearrangement without clonal variation. Two-colour fluorescence in situ hybridization (X and Y chromosomes) and microsatellite genotyping were used to compare samples from the patient (transplant recipient), his sister (donor) and the skin biopsy sample, which confirmed that the origin of the neoplastic cells was the donor graft. To our knowledge, this is the first case of post-transplant primary cutaneous T-cell lymphoproliferative disorder after ASCT.