Verification of musculoskeletal FDG-PET-CT findings performed for melanoma staging.
BACKGROUND
The purpose of this study is to establish the validity of F-18-deoxyglucose positron emission tomography-computed tomography (FDG-PET-CT) scan staging for cutaneous melanoma when a musculoskeletal image abnormality is detected.


METHODS
An institutional review board (IRB)-approved prospective database was queried to identify 342 melanoma patients treated between 4/1999 and 12/2007. A total of 682 whole-body FDG-PET-CT scans performed for staging were retrospectively reviewed to identify FDG-avid lesions in the deep soft tissues/muscle, bone or joints (i.e., musculoskeletal sites). Images were correlated with follow-up patient records.


RESULTS
There were 187 true-positive sites on 94 scans and 26 false-positive sites on 22 scans. The overall false-positive rate was 13.9% (26/187). The positive predictive value (PPV) of an isolated musculoskeletal FDG-avid site was 31%. The PPV was highest (100%) when findings were present in both the bone and deep soft tissues. The relative risk of an isolated FDG-avid site compared with multiple FDG-avid sites not being melanoma was 5.33 [95% confidence interval (CI) 2.85-9.94]. The relative risk of an FDG-avid site seen in the appendicular region not being melanoma was 1.78 (95% CI 0.87-3.64) that of a site seen in the axial region.


CONCLUSIONS
FDG-PET-CT scanning for staging and surveillance in the extremities of patients with high-risk melanoma often creates confusing clinical scenarios. Our data suggest that a select subset of patients with isolated avid appendicular musculoskeletal scan may not have metastatic melanoma.
Mansour
Alfred A
AA
Department of Orthopaedic Surgery, Vanderbilt University Medical Center, Nashville, TN, USA. alfred.mansour@vanderbilt.edu
Kelley
Mark C
MC
Hatmaker
Allison R
AR
Holt
Ginger E
GE
Schwartz
Herbert S
HS
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging / Q000473:pathology*; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011379:Prognosis; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D012878:Skin Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology*; D015996:Survival Rate; D014057:Tomography, X-Ray Computed; D055815:Young Adult
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18