18F-Fluorodeoxyglucose Positron Emission Tomography Does Not Predict Malignancy in Thyroid Nodules Cytologically Diagnosed as Follicular Neoplasm

• Published in: The journal of clinical endocrinology and metabolism 2007-05, Vol.92 (5), p.1630-1634
• Main Authors: Kim, Jung Min, Ryu, Jin-Sook, Kim, Tae Yong, Kim, Won Bae, Kwon, Gui Young, Gong, Gyungyub, Moon, Dae Hyuk, Kim, Seong Chul, Hong, Suck Joon, Shong, Young Kee
• Format: Article
• Language: English
• Subjects: Adenoma - diagnostic imaging; Adenoma - pathology; Adenoma - surgery; Adenoma, Oxyphilic - diagnostic imaging; Adenoma, Oxyphilic - pathology; Adenoma, Oxyphilic - surgery; Adult; Aged; Biological and medical sciences; Biopsy, Fine-Needle; Diagnosis, Differential; Endocrinopathies; Female; Fluorodeoxyglucose F18; Fundamental and applied biological sciences. Psychology; Glucose - metabolism; Humans; Male; Medical sciences; Middle Aged; Non tumoral diseases. Target tissue resistance. Benign neoplasms; Positron-Emission Tomography; Radiopharmaceuticals; Thyroid Nodule - diagnostic imaging; Thyroid Nodule - pathology; Thyroid Nodule - surgery; Thyroid. Thyroid axis (diseases); Vertebrates: endocrinology
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jc.2006-2311

Objective: The objective of this study was to evaluate the usefulness of 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) in predicting malignancy in thyroid nodules cytologically diagnosed as follicular neoplasm. Patients and Methods: A total of 46 patients with thyroid nodules larger than 1 cm in diameter cytologically diagnosed as follicular neoplasm at Asan Medical Center (Seoul, Korea) were included. FDG-PET images were taken in all patients before surgical resection, and the maximum standardized uptake value (SUVmax) of each nodule was measured. Results: FDG-PET showed hypermetabolic activity of all nodules compared with normal thyroid tissue. Thirty-six patients underwent surgery, whereas 10 refused immediate operation. Fifteen patients had cancer: 11 with follicular and two each with Hürthle cell and follicular variants of papillary cancer. Twenty-one patients had benign nodules: 11 follicular adenomas, eight adenomatous hyperplasias, and two Hürthle cell adenomas. SUVmax did not differ significantly between malignant and benign nodules (3.6 ± 3.5 vs. 3.4 ± 3.2; P = 0.83) or among subtypes of benign nodules (P = 0.23). However, SUVmax differed significantly among subtypes of malignant nodules (P = 0.02). Conclusions: On FDG-PET, the glucose metabolic activities of benign thyroid follicular nodules were as high as those of malignant nodules. These findings suggest that FDG-PET has limited value for selecting candidates for surgery among patients cytologically diagnosed as follicular neoplasm.