CD30+ primary cutaneous post-transplant lymphoproliferative disorder with signet-ring cell features

We report a case of primary cutaneous CD30+ post-transplant lymphoproliferative disorder with an uncommon finding of signet ring cell features in a heart transplant patient. The neoplastic cells were CD4 and CD30 positive, and negative for S-100, pancytokeratin, myeloperoxidase, and CD56. In situ hybridization for Epstein Barr Virus (EBV) was negative, even though the patient did have EBV viremia.