FDG PET/CT Findings of Polymorphic Posttransplant Lymphoproliferative Disorders in a Transplanted Kidney

Solitary Central Nervous System Relapse of Posttransplant Lymphoproliferative Disorder on 18F-FDG PET/CT

ABSTRACT

A 41-year-old woman received stem cell transplant due to acute myeloid leukemia. Six months after the stem cell transplant, the patient experienced monomorphic PTLD (posttransplant lymphoproliferative disorder) and underwent chemotherapy. Postchemotherapy PET/CT did not show any abnormal 18F-FDG accumulation in the scanned body, including brain. Four months later, she presented with nausea and vomiting. Brain MRI showed a lesion in the right temporal lobe. In addition to the abnormal 18F-FDG accumulation in the brain, no other abnormal foci were noted in the torso PET/CT. Biopsy pathology confirmed the diagnosis of monomorphic PTLD.

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

ABSTRACT

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.

FDG PET/CT Findings of Melanoma in a Renal Allograft

Renal melanoma is rare. We present a case with FDG-avid melanoma arising from renal allograft. This case indicates that melanoma can occur in the allograft, and it should be considered as a differential diagnosis of focal abnormal FDG uptake in the renal allograft.

Roles of PET/Computed Tomography in the Evaluation of Neuroblastoma

Neuroblastoma is one of the most common pediatric malignant tumors. Functional imaging plays an important role in the diagnosis, staging, and therapy response monitoring of neuroblastoma. Although metaiodobenzylguanidine scan with single-photon emission computed tomography/computed tomography remains the mainstay in functional imaging of the neuroblastomas, PET/CT has begun to show increased utility in this clinical setting.