Utility of 18F-FDG PET/CT in the diagnosis and staging of extramammary Paget's disease.
OBJECTIVE
Extramammary Paget's disease (EMPD) is rare, and limited data have been reported on the utilization of fluorine-18 fluorodeoxyglucose PET/computed tomography ((18)F-FDG PET/CT) in this disease. The aim of this study is to evaluate the role of (18)F-FDG PET/CT in the diagnosis and staging of EMPD.


METHODS
Whole-body (18)F-FDG PET/CT images of 10 patients with newly diagnosed or recurrent EMPD were retrospectively analyzed. The lesion with increased (18)F-FDG uptake was considered positive and was measured using the maximum standardized uptake value (SUV(max)). The results of PET/CT were compared by conventional staging examinations.


RESULTS
All malignant lesions showed increased (18)F-FDG uptake, except for some small lung metastases. Whole-body (18)F-FDG PET/CT detected all primary lesions in four newly diagnosed patients and recurrences in the primary sites in two patients. Two thick lesions showed intense uptake of (18)F-FDG (SUV(max): 14.9 and 7.5) whereas four thin lesions had only mild (18)F-FDG uptake (mean SUV(max): 3.25 ± 0.24). A false-positive result was found in one patient with suspected primary recurrence. (18)F-FDG PET/CT also detected lymph node metastases in six patients, bone metastases in five patients, liver metastases in two patients, lung metastases in one patient, and an adrenal gland metastasis in one patient. Compared with conventional staging examinations, three of 10 patients were upstaged by PET/CT.


CONCLUSIONS
(18)F-FDG PET/CT diagnosis of primary lesions in EMPD is mainly dependent on the thickness of the lesions, whereas it is more sensitive for the diagnosis of metastases.
aNanFang PET Center bMedical Imaging Center, Nanfang Hospital, Southern Medical University, Guangzhou, China.
Ying
Y
Tian
Hu-Bing
HB
Wu
Dong-Li
DL
Li
Hong-Sheng
HS
Li
Wen-Lan
WL
Zhou
Quan-Shi
QS
Wang
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D009367:Neoplasm Staging; D010145:Paget Disease, Extramammary / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000473:pathology*; D049268:Positron-Emission Tomography; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
D019788:Fluorodeoxyglucose F18