Active surveillance (AS) of small, low-risk papillary thyroid cancers (PTCs) is increasingly studied in prospective observational studies. Ultrasound is the primary imaging modality for case selection. While researchers have put forward selection criteria for PTCs based on size, absence of suspicious lymph nodes and tumor location, there are limited reported data highlighting inherent ultrasound limitations and guidelines for case selection and follow-up. We report our experience including imaging limitations encountered in the ongoing AS prospective observational study for PTCs measuring < 2 cm at our institute. We define disease progression as an increase in size of > 3 mm in the largest dimension of nodule or evidence of metastatic disease or extrathyroidal extension. Accurate, consistent and reproducible measurements of PTCs are essential in risk stratifying patients for the option of AS or disease progression. Interobserver discrepancy, shadowing from coarse calcification and background parenchyma heterogeneity or thyroiditis can limit accurate PTC size assessment and therefore hinder patient eligibility evaluation or AS follow-up. Following the ACR Thyroid Imaging, Reporting and Data System (TI-RADS) protocol of three-axes technique to measure a thyroid nodule enables reproducibility of measurements. In patients with multi-nodular goiter, accurate identification and labeling of the PTC is important to avoid mistaking with adjacent benign nodules at follow-up. Ultrasound assessment for extrathyroid extension of PTC, and relationship of PTC to trachea and the anatomic course of the recurrent laryngeal nerve are important considerations in evaluation for AS eligibility.

Colon carcinoma metastases to the thyroid are a rare phenomena. Here we report a case of multiple malignant neoplasms where an incidental diagnosis of colon cancer was made after pathologic evaluation of the thyroid specimen.

Most thyroid cancers (90-95%) are well differentiated. Well differentiated cancers of the thyroid are usually confined to the thyroid capsule, making them amenable to isolated thyroid resection. Invasion of the upper aerodigestive tract by these cancers is infrequent and hypopharyngeal invasion is still rare. We report a 51 year old man with thyroid cancer invading the hypopharynx, who was successfully managed with complete resection along with a partial pharyngectomy. He is asymptomatic and disease free eighteen months after surgery. We advocate aggressive surgical extirpation of thyroid carcinoma invading the upper aerodigestive tract.