Ultrasonographic and cytologic assessments of follicular neoplasms of the thyroid: Predictive features differentiating follicular carcinoma from follicular adenoma

• Published in: PloS one Vol. 17; no. 7; p. e0271437
• Main Authors: Ahn, Hye Shin, Kim, Hee Sung, Hong, Min Ji
• Format: Journal Article
• Language: English
• Published: San Francisco Public Library of Science 21.07.2022; Public Library of Science (PLoS)
• Subjects: Adenoma; Biology and Life Sciences; Biopsy; Cancer; Carcinoma; Cellular biology; Diagnosis; Differential diagnosis; Evaluation; Medical diagnosis; Medicine and Health Sciences; Neoplasms; Nodules; Patients; Reviews; Risk factors; Thyroid; Thyroid cancer; Thyroid gland; Thyroidectomy; Tumors; Ultrasound imaging; South Korea; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0271437

Background The preoperative diagnosis of follicular neoplasm of the thyroid is challenging due to difficulties in the assessment of capsular invasion. This study aimed to identify ultrasonographic (US) and cytopathologic features that are characteristic of follicular adenoma and carcinoma to aid in their differential diagnosis. Methods A total of 98 surgically resected nodules diagnosed as follicular neoplasms between 2011 and 2012 were analyzed. US findings were reviewed according to the Korean Thyroid Imaging Reporting and Data System (K-TIRADS). Six cytologic features (high cellularity, abundant microfollicles, cell crowding/nuclear overlapping, isolated cells, homogeneous nuclei, abundant colloid) were reviewed quantitatively. The radiologic findings and quantification of cytologic features were correlated with final diagnoses. Results In total, 70 (71.4%) and 28 (28.6%) of the nodules were follicular adenomas and follicular carcinomas, respectively. US findings of a heterogeneous echogenicity, speculated/ill-defined margin, and presence of calcifications were significantly associated with follicular carcinoma (p<0.05). Calcifications had a predilection for pericapsular areas than for stromal areas in follicular carcinomas, whereas their location was more varied in follicular adenomas. No cytologic feature was significantly different between follicular adenomas and carcinomas. Conclusion Distinct from follicular adenomas, follicular carcinomas are characterized by heterogeneous echogenicity, speculated/ill-defined margin, and presence of calcifications on US. Thus, US findings can be helpful to differentiate between these two follicular neoplasms.