Role of (18)F-fluorodeoxyglucose positron emission tomography imaging in the management of primary cutaneous lymphomas.

Primary cutaneous lymphomas (PCLs) include both cutaneous T-cell and B-cell lymphomas and comprise the second most common type of extra-nodal non-Hodgkin's lymphomas. The treatment and prognosis of PCLs typically depend on the extent of disease. In evaluating extent of disease in oncological processes, computed tomography (CT) provides a purely anatomical assessment of disease. In comparison, [(18)F]-fluorodeoxyglucose positron emission tomography ((18)F-FDG PET) both visualizes and quantifies the biological processes occurring in the disease at the cellular level. This paper reviews the available literature addressing the clinical role of (18)F-FDG PET both alone and in combination with CT in PCLs and draws several conclusions. While (18)F-FDG PET seems superior to CT in its detection of nodal and cutaneous PCL lesions, (18)F-FDG PET does not seem to adequately detect erythroderma, plaque, or patch cutaneous PCL lesions. In addition, several case series have demonstrated that physicians may be able to use the semi-quantitative measurement of (18)F-FDG uptake provided by (18)F-FDG PET to predict which lesions are most aggressive. Other case series have shown that the integrated (18)F-FDG PET/CT may provide an objective measure of treatment response in patients with PCLs.