A case of posttransplant lymphoproliferative disorder (PTLD) presenting as an isolated skin lesion is reported. An initial superficial biopsy of the lesion was diagnosed as squamous cell carcinoma. After pathologic review of the biopsy and staining for immunoglobulins and Epstein-Barr virus (EBV) DNA, the correct diagnosis of PTLD was made. The patient had no systemic manifestations of lymphoma and the skin lesion was successfully treated with excision. Isolated skin lesions should be included among the potential sites for PTLD and histologic skin specimens from posttransplant immunosuppressed patients should be examined carefully for PTLD.