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Clinical Significance of Incidental 18F-FDG Uptake in the Pyriform Sinus Detected by PET/CT

Cho, Young Seok MD, PhD; Moon, Seung Hwan MD, PhD; Choi, Joon Young MD, PhD; Choe, Yearn Seong PhD; Kim, Byung-Tae MD, PhD; Lee, Kyung-Han MD, PhD

doi: 10.1097/RLU.0000000000000992
Original Articles

Purpose We investigated the significance of unexpected focal pyriform sinus FDG uptake and determined the ability of PET/CT parameters to identify malignancy.

Materials and Methods FDG PET/CT reports of 56,585 consecutive subjects were retrospectively reviewed, and 281 cases (0.50%) with focal pyriform sinus uptake were included. PET images were assessed for maximum standardized uptake values (SUVmax) and asymmetric indices of FDG activity, and CT images were evaluated for pyriform sinus narrowing. The final diagnosis was determined by tissue biopsy, laryngoscopy, radiological findings, and clinical follow-up.

Results Among the 281 subjects, final diagnosis was pyriform sinus malignancy in 29 (10.3%) and benignity in 215 cases (76.5%). Malignant lesions had significantly higher SUVmax (9.13 ± 3.64 vs. 3.53 ± 1.01) and asymmetric index (4.16 ± 1.81 vs. 1.54 ± 0.39) compared to benign causes. Patients with malignant lesions also had higher cervical lymph node SUVmax (6.66 ± 8.79 vs. 2.76 ± 2.46, all P < 0.001). Lesion SUVmax ≥4.24 identified malignancy with a sensitivity of 93.1% and specificity of 86.5%. Asymmetric index ≥1.81 had a sensitivity of 100% and specificity of 89.7%.

Conclusion Incidentally identified focal pyriform sinus uptake on FDG PET/CT should be evaluated for possible malignancy in the presence of high SUVmax or asymmetric index.

From the Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Korea.

Received for publication May 13, 2015; revision accepted August 10, 2015.

Conflicts of interest and sources of funding: none declared.

Presented in part at the Annual Meeting of The Korean Society of Nuclear Medicine, November 7, 2014: Seoul, Korea.

Correspondence to: Kyung-Han Lee, MD, PhD, Department of Nuclear Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Irwon-dong, Gangnam-gu, Seoul 135-710, Korea. E-mail:

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