Abstract
2709
Introduction: Primary cutaneous lymphoma (PCL) is a non-Hodgkin’s lymphoma (NHL) that originates in the skin and displays no extracutaneous spread upon initial diagnosis. The prognosis of this disease is directly correlated to disease stage. Therefore, the earlier it is detected, the better the prognosis. While conventional imaging methods, primarily computed tomography (CT), may be sensitive for detection of extracutaneous disease, it is not as successful at detecting malignant cutaneous lesions. FDG-PET/CT is more specific and sensitive for the detection of malignant lesions than any other imaging modality currently available. As of 2018, the World Health Organization–European Organization for Research and Treatment of Cancer (WHO-EORTC) now recommends that FDG-PET/CT imaging be performed during the staging and monitoring of all primary cutaneous lymphomas with subcutaneous presentation, deeming FDG-PET/CT essential to determine the extent of disease. The objective of this scoping review was to determine the extent to which FDG-PET/CT imaging has been applied to patients with PCL. We would like to summarize current research conclusions on the utility of FDG-PET/CT in diagnosing, staging, and monitoring PCL. As the prognosis of PCL is directly correlated to disease stage, imaging modalities that allow for earlier detection of disease may improve morbidity and mortality.
Methods: Scoping search yielded 231 results. Nine studies were included in this scoping review. These studies were selected by utilizing Google scholar search engine. A search for articles containing the exact phrase “primary cutaneous lymphoma” AND at least one of the words “positron emission tomography” OR “PET CT” OR "positron emission tomography computed tomography" yielded 231 results. Of these results, only scientific studies were included that were published 2014 or later, pertained to primary cutaneous lymphoma, used FDG-PET/CT as imaging modality, and included equal to or more than 9 human subjects. After performing the literature search as described, a total of 9 articles were reviewed and included in this paper.
Results: Of the nine studies included in this scoping review, all nine concluded that FDG-PET/CT was superior to CT alone in the detection of high-grade PCL lesions and should be the preferred method of imaging for staging and monitoring disease response to treatment. It was also noted that FDG-PET/CT may prove useful in guiding lymph node biopsies. The limitations of FDG-PET/CT were discussed, noting that while PET was very sensitive for detecting aggressive cutaneous lesions, it was poor at detecting indolent cutaneous lesions. Therefore, it was emphasized that nonattenuated PET images should be evaluated in addition to the corrected images, to avoid overlooking indolent lesions that may not show up well on the corrected scans.
Conclusions: All studies between 2014 to 2021 conclude that FDG-PET/CT is far more sensitive and specific for aggressive-behaving cutaneous lymphoma lesions than CT. FDG-PET/CT is scientifically proven to be the superior imaging method for detecting high-grade PCL lesions in both initial staging as well as monitoring disease progression. Limitation of this imaging modality is poor sensitivity for detection of indolent cutaneous lesions, and therefore it is suggested that nonattenuation corrected scans be evaluated in addition to corrected scans. By providing more accurate staging, both at initial diagnosis, and during follow-up visits, FDG-PET/CT may improve the prognostic outcome of aggressive-behaving PCL disease.