Primary Cutaneous Natural Killer/T-Cell Lymphoma: A Posttransplant Lymphoproliferative Disorder Demonstrated by 18F-FDG PET/CT.

A 24-year-old man with a history of hemophagocytic lymphohistiocytosis (HLH) presented with swelling of the left foot and skin ulcer. The patient received bone marrow transplantation for HLH 3 years ago for his HLH. Biopsy of left foot skin demonstrated primary cutaneous natural killer/T-cell lymphoma: a posttransplant lymphoproliferative disorder. FDG PET/CT images demonstrated multiple foci of abnormal accumulation in the body, especially in the skin. Follow-up PET/CT after chemotherapy demonstrated that most abnormal activities disappeared except for the lesion in the left foot.