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Study Establishes SUVmax Cutoffs to Discriminate Benign and Malignant Lesions in the Palatine Tonsils

by Linda Kossoff •

What is the prevalence of palatine tonsil malignancy in immunofluorescence testing (IFT), what are the potential malignancy risk factors, and what are the optimal cutoffs of maximum standardized uptake values (SUVmax) to discriminate benign from malignant lesions?

BOTTOM LINE

Tonsillectomy for patients with IFT displaying SUVmax >9.0, ratio >1.5, or symptoms or findings suggesting malignancy is recommended.

BACKGROUND: The number of applications for fluorodeoxyglucose-positron emission tomography (FDG-PET)/computed tomography (CT) continues to increase for oncological and non-oncological conditions and, thus, so do the number of incidental focal FDG-avid findings. No previous studies have explored tonsillar findings in IFT and, therefore, no studies report on SUVmax values to discriminate benign from malignant lesions within IFT.

STUDY DESIGN: Retrospective cohort study.

SETTING: Department of Otorhinolaryngology–Head and Neck Surgery, Aarhus University Hospital, Aarhus, Denmark.

SYNOPSIS: Researchers scoured the records of 754 patients aged >30 years who were tonsillectomized for any reason at a single institution between Oct. 1, 2011, and Dec. 31, 2020. In total, 77 patients undergoing bilateral or unilateral tonsillectomy (60 and 17 patients, respectively) because of IFT were included. Tonsillar histology examinations revealed malignancy in 11 (14%) patients. A significant proportion of patients with tonsillary malignancy did not have symptoms (64%) or clinical findings (36%) suggestive of tonsillar malignancy. Anamnestic dysphagia and alcohol abuse were significantly associated with malignancy. One patient with synchronous bilateral squamous cell carcinoma (SCC) and one patient with SCC in one tonsil had high-grade dysplasia in the contralateral tonsil; authors say this underscores the importance of not relying solely on side-to-side tonsillar SUVmax asymmetry for selecting patients for tonsillectomy. Overall, absolute SUVmax cutoff was superior to SUVmax side-by-side ratio in discriminating between benign and malignant lesions. Authors advocate for tonsillectomies in all patients with symptoms or objective findings suggesting tonsillar malignancy despite normal FDG uptake on PET/CT. Study limitations include the possibility of missed patients as some with IFT may not have been tonsillectomized.

CITATION: Reinholdt KB, Dias AH, Hoff CM, et al. Incidental FDG-avid focuses in palatine tonsils on PET/CT. Laryngoscope. 2022;132:2370-2378.