Characterization of T-cell lymphomas by FDG PET/CT

The purpose of this article is to describe the utility of FDG PET/CT in documenting sites of disease in patients with T-cell lymphomas, to quantify the degree of FDG avidity in the various subtypes of this heterogeneous group of disorders, and to highlight the pattern of imaging findings associated with specific disease subtypes.

A retrospective review of patients with T-cell lymphomas who underwent PET/CT examination for initial disease staging or at disease relapse over a 5-year period was undertaken by correlation between a patient database and a PACS radiology information system. Disease subtypes were grouped according to World Health Organization categorization of mature natural killer cell-T-cell neoplasms. Sites of disease involvement were documented according to cutaneous or extranodal, nodal, and visceral locations. The maximum standardized uptake value (SUV) was recorded for each patient.

One hundred thirty-five patients with T-cell lymphoma were included, and sites of disease were documented by use of FDG PET/CT in 122 (90%) patients. Of those 122 patients, 55 (45%) had cutaneous involvement, 95 (78%) had FDG-avid lymphadenopathy, and 54 (44%) had FDG-avid extranodal disease other than cutaneous involvement. A significant difference in maximum SUV was observed in cases of mycosis fungoides and mycosis fungoides with large cell transformation (SUV, 11.3 vs 3.8; p < 0.05).

We found high rates of FDG positivity in T-cell lymphoma. Given the propensity for disease involvement outside the normal scan range of diagnostic CT, we recommend that patients with T-cell lymphoma be scanned from vertex to feet by use of PET/CT.