Up to two-thirds of thyroid ultrasound examinations will reveal nodules, though only a small percentage prove to be malignant. Fine-needle aspiration cytology (FNAC) can help distinguish between malignant and benign tissue, but the test is not cost-effective in every case.
Recent work—led by Carlos Miguel Oliveira with the radiology department at the Hospitais da Universidade de Coimbra Praceta Mota Pinto in Coimbra, Portugal—tried to establish feature-oriented criteria to help determine which nodules are malignant.
“A combination of ultrasound features that can distinguish between nodules that require biopsy and ‘leave alone’ nodules is crucial in the workup of the patients with thyroid nodules,” Oliveira et al. wrote.
The study was published online Nov. 16 in Academic Radiology.
The team examined records of 379 FNAC studies throughout 2013, identifying 357 patients (311 women and 46 men with an average age of 59.6 years old). All individuals underwent surgery or remained in follow-up for a year if the nodule was benign.
Of all the nodules examined, 29 were found to be malignant. Those with malignant modules were younger (54.1 years vs. 60.4 years), with no difference in gender.
Other significant findings include:
- Of the 29 nodules that were classified as malignant, 27 were papillary carcinomas, and seven were diagnosed as follicular variant.
- No relationship was discovered between diagnosis and nodule size. (Eight malignant tumors were smaller than 15 mm and 21 were larger than 15 mm. In the benign group, 42 were smaller than 15 mm and 229 were larger than 15 mm.)
- Malignant tumors were associated with ill-defined contours (P=0.041), taller-than-wide shape (P=0.007), peripheral halo (P=0.044) microcalcifications (P=0.010) and adenopathy (P=0.001).
The research team found any nodules with these suspicious features should be referred to FNAC. Conversely, the authors recommend nodules with no such features should not be submitted to FNAC.
“In the presence of multiple nodules, the radiologist should always perform the FNAC on the ones that show a taller-than-wide shape, microcalcifications, a peripheral halo, or an ill-defined contour,” Oliveira et al. wrote. “If one of these features is present, the overall sensitivity increases up to 89.7 percent.”