Head and neck incidentalomas on positron emission tomographic scanning: ignore or investigate?

Background And Objective: Incidental head and neck abnormalities are increasingly detected with 18F-fluorodeoxyglucose positron emission tomography (FDG-PET). Incidental thyroid lesions on PET are described in many studies; however, no reports have definitively identified incidental findings in multiple head and neck sites. The aim of this study was to (1) review the related literature, (2) identify the incidence and significance of head and neck incidentalomas on PET/computed tomography (CT) scanning, and (3) attempt to establish management recommendations for head and neck PET incidentalomas.

Study Design: Retrospective study.

Setting: Tertiary care centre.

Methods: Head and neck incidentaloma cases from whole-body 18F-FDG PET/CT scans were reviewed based on specific inclusion criteria from January 2009 to January 2010 at the Jewish General Hospital. The patients had been scanned for known or suspected malignant lesions in non-head and neck sites. Patients with incidental head and neck abnormalities were identified.

Results: The scans of 38 of 1565 (2.43%) subjects who underwent FDG-PET scanning for known or suspected cancer demonstrated head and neck incidentalomas. In 8 of 38 cases (21.05%), malignancies were discovered in the incidentaloma lesion (5 thyroid, 2 parotid, and 1 cervical lymph node), and all were new primary malignancies. Five of the 8 (62.5%) demonstrated significantly high standard uptake value (SUV).

Conclusion: Head and neck PET/CT incidentalomas are quite common. A significantly high SUV strongly suggests the presence of malignancy. Head and neck incidentalomas merit consultation and further evaluation.