Composite B-cell and T-cell Lineage Post-transplant Lymphoproliferative Disorder of the Lung with Unusual Cutaneous Manifestations of Mycosis Fungoides

We present the case of a 17-year-old male kidney transplant recipient who presented initially with dermatologic symptoms and was found to have histologic changes in the skin that were consistent with mycosis fungoides. Shortly after this diagnosis was made, imaging studies demonstrated multifocal interstitial and airspace consolidation in both lungs. Physical examination revealed no lymphadenopathy or hepatosplenomegaly, but an open lung biopsy revealed an Epstein-Barr virus (EBV)-negative monomorphic T-cell posttransplant lymphoproliferative disorder (PTLD) with a concomitant EBV-positive B-cell PTLD involving the same lesion of the lung. Polymerase chain reaction analysis demonstrated clonal T-cell receptor gene rearrangements in both the skin and the lung biopsies. Interestingly, 1 clone was shared between the skin and lung while a second clone was present only in the lung. To our knowledge, this is the first reported case of a PTLD presenting in the skin in which there was a subsequent discovery of composite, bilineal B-and T-cell PTLD of the lung.