Solid/trabecular subtype of papillary thyroid carcinoma on cytology with focal differentiated high-grade thyroid carcinoma on histology: a cyto-histologic correlation.

Solid/trabecular subtype of papillary thyroid carcinoma (S/T PTC) is a rare entity that has been shown to have higher tumour recurrence and mortality rates. A definite diagnosis on fine needle aspiration cytology is often not easy. Rather, this entity may be misdiagnosed in cytology due to a lack of widespread features of classic PTC. We present a case of S/T PTC in a 61-year-old female, showing a focus on differentiated high-grade thyroid carcinoma (DHGTC) on histology. We discuss cytological features with the histologic correlation of S/T PTC and briefly discuss the newly introduced entity, DHGTC.