Partially cystic thyroid nodules: ultrasound findings of malignancy

To seek for the ultrasound (US) findings of partially cystic thyroid nodules that are associated with malignancy.

We reviewed the US characteristics of 22 surgically confirmed partially cystic papillary carcinomas, and compared them with those of 80 benign partially cystic nodules. The review cases were selected in a random order from a total of 1029 partially cystic nodules that were diagnosed with an US-guided fine needle aspiration biopsy over a period of 8 years (June 2003 to October 2010) at our institution.

In partially cystic thyroid nodules, a taller-than-wide shape (100%, p < 0.001) and spiculated or microlobulated margin (58.3%, p = 0.003) were significantly associated with malignancy. In terms of internal solid portion of the nodule, eccentric configuration (68.0%, p < 0.001), non-smooth margin (81.3%, p < 0.001), hypoechogenecity (30.0%, p < 0.042), and microcalcification (89.5%, p < 0.001) were more frequently demonstrated in malignant nodules than benign ones.

In partially cystic thyroid nodules, understanding the characteristics of US findings is important to make a precise diagnosis of malignant nodules.