18F-FDG PET/CT to differentiate malignant necrotic lymph node from benign cystic lesions in the neck.
OBJECTIVE
Patients presenting with cystic lesions in the neck without obvious signs of malignancy constitute a diagnostic challenge since fine needle aspiration is often insufficient and a diagnosis may not be reached until surgical resection/biopsy is performed. The differential diagnosis of a cystic cervical mass comprises a variety of benign conditions, but malignancy must be ruled out. We examined the diagnostic performance of fluorine-18 fluorodeoxyglucose (18F-FDG) PET/CT to identify malignancy.


METHODS
We retrospectively included consecutive patients referred from the Department of ENT Head and Neck Surgery for 18F-FDG PET/CT-scans because of a solitary neck cyst. Scan results were compared to histopathology and follow-up.


RESULTS
The study comprised 58 patients. Twenty patients (34%) were diagnosed with cancer during follow-up. PET/CT suggested malignancy in 34 patients (19 true positive, 15 false positive) and showed no malignancy in 24 (23 true negative, 1 false negative). The sensitivity, specificity, accuracy, positive and negative predictive values were 95% (76-99%), 61% (45-74%), 72% (60-82%), 56% (39-71%), and 96% (80-99%), respectively (95% confidence intervals in brackets). The primary tumor was identified in 14 out of the 20 patients with confirmed cancer. Increased metabolism, as evaluated by PET, was the only imaging characteristic among several others, which associated independently with malignancy in the cystic neck lesions, odds ratio 1.27 (1.07-1.50), p = 0.006.


CONCLUSION
18F-FDG PET/CT could reliably rule out malignancy (NPV 96%), albeit with a high frequency of false positive scans, requiring further diagnostic work-up. Increased metabolism was the best imaging parameter to differentiate between malignant and benign lesions.
['Abadi|Peymaneh|P|http://orcid.org/0000-0002-5678-4604', 'Johansen|Allan|A|', 'Godballe|Christian|C|', 'Gerke|Oke|O|', 'Høilund-Carlsen|Poul Flemming|PF|', 'Thomassen|Anders|A|']
D000328:Adult D000368:Aged D000369:Aged, 80 and over D003937:Diagnosis, Differential D005260:Female D019788:Fluorodeoxyglucose F18 D005500:Follow-Up Studies D006258:Head and Neck Neoplasms D006801:Humans D008198:Lymph Nodes D008210:Lymphocele D008223:Lymphoma D008297:Male D008875:Middle Aged D009336:Necrosis D000072078:Positron Emission Tomography Computed Tomography D019275:Radiopharmaceuticals D012189:Retrospective Studies D012680:Sensitivity and Specificity D055815:Young Adult
Necrotic lymph node Neck cyst Branchial cleft cyst Cervical metastasis FDG PET/CT PET/CT in cervical cystic lesions