FDG-PET/CT in the evaluation of cutaneous T-cell lymphoma

This comprehensive case series illustrates the findings on 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) positron-emission tomography/computed tomography (PET/CT) of patients with varying stages of cutaneous T-cell lymphoma (CTCL). Patients were imaged with full-body scanning using a General Electric Discovery ST 16-slice PET/CT machine. Patients were assessed by PET/CT for cutaneous, nodal, and solid organ FDG uptake, indicative of highly metabolically active (i.e., putatively malignant cells) disease, and comparisons were made to CT data alone and to the physical examination. Several key observations strongly suggested that information afforded by PET/CT scan may be valuable. Various cutaneous lesions, from thin subtle plaques to thick tumors, were revealed and corresponded accurately to the cutaneous examination. In the case of subcutaneous lesions, PET/CT outperformed physical exam. CT also provided the depth/thickness of lesions. The differing levels of FDG uptake in enlarged nodes found within an individual patient as well as among different patients may potentially distinguish reactive from malignant adenopathy. Additionally, lymph nodes that did not meet staging size criteria (e.g., were not >1 cm) revealed increased metabolic activity and, therefore, could be targeted for subsequent monitoring or biopsy. In addition, PET/CT identified visceral involvement in cases with advanced disease. In summary, PET/CT can provide physiologic and anatomic information on the wide diversity of external and internal lesions in CTCL and, therefore, may have great potential for improving the staging and monitoring of response to therapy of cutaneous, nodal, and visceral disease.