Atypical cutaneous targetoid lesions after bone marrow transplant.

A 69-year-old man with esophageal EBV-positive diffuse large B cell lymphoma status post allogeneic bone marrow transplant (BMT) five months prior presented to his oncologist with three days of maculopapular rash that was initially diagnosed as grade 1 graft-versus-host disease and started on oral prednisone. However, due to worsening of the rash, the patient presented to dermatology clinic, where skin biopsy revealed a diagnosis of erythema multiforme (EM). The patient improved with the use of topical steroids. This case highlights the atypical morphology of post-BMT EM and the potential causes for this atypical appearance.