Cystic papillary thyroid carcinoma in fine needle aspiration may represent a subset of the encapsulated variant in WHO classification

Abstract

This study audits the reliability of ultrasound-guided fine needle aspiration (FNA) in excluding papillary thyroid carcinoma (PTC) in thyroid cysts containing mural nodules, and investigates the histological counterpart of cystic PTC diagnosed on FNA. Using a 10-5 MHz ultrasound probe and a 27-gauge needle, solid portions of thyroid nodules were sampled and assessed immediately using both Diff-Quik and Ultrafast Papanicolaou stains. Unlike usual PTCs that demonstrate hypercellularity, the aspirates of cystic PTC showed low cellularity and consisted of papillae with atypical nuclei scattered in abundant thin colloid. Over a period of 13 years, histological follow-up was obtained from 11 women and 6 men in whom cystic PTC was reported on FNA. This represented 4.4% of 383 cases of PTC reported and 0.25% of all thyroid FNAs performed. In all 17 cases, histopathology showed encapsulated PTC in various stages of cystic degeneration. Sonography correlated well with histopathology, where findings ranged from cysts with small mural nodules to solid nodules with pockets of thin colloid. In 87 patients with thyroid cysts containing mural nodules, FNA findings were benign, as was clinical follow-up that ranged from 1 to 12 years. In conclusion, ultrasound-guided FNA, if performed in the manner described, can reliably distinguish cystic PTC from a benign cyst with a mural nodule. Cystic PTC on FNA in this series correlates to a subset of the encapsulated variant of PTC, an entity described in the 1988 WHO Histological Typing of Thyroid Tumours in the good prognostic category.

Cytomorphological Factors and BRAF Mutation Predicting Risk of Lymph Node Metastasis in Preoperative Liquid-Based Fine Needle Aspirations of Papillary Thyroid Carcinoma

“…In addition, we investigated the role of HF in FNAB samples as an independent predictor of outcome regardless of the histologic PTC variant. To achieve this, cystic-variant PTC was previously classified with corresponding tissue samples based on histopathologic criteria showing encapsulated tumors with various degrees of cystic degeneration [12]. In addition, the relationship between HF and cytomorphologic characteristics including cytoplasmic vacuoles and background macrophages was also evaluated.…”

Conventional papillary thyroid carcinoma: effects of cystic changes visible on ultrasonography on disease prognosis

“…To distinguish benign nodules from malignancy in partially cystic thyroid nodules, US features such as eccentric configuration and presence of microcalcifications within the solid portion can be of help in an accurate diagnosis of thyroid malignancy [22,25-27]. Although US features and cytopathologic characteristics of cystic PTC have been established [3,4,9,25,26], studies on PTC showing a cystic change on US focus on its behaviors, in comparison to solid-appearing thyroid cancers on US, and its prognosis has not yet been demonstrated. In this study, we investigated the nature of PTC with a cystic change on US.…”

“…Cystic PTC can manifest as either cystic or solid masses on US [9]. This imaging-pathologic discordance—a mass appearing solid on US, but diagnosed as cystic PTC on pathology—is due to cystic changes within the mass that are too small to be detected on US [9]. Although we often come across PTCs with a cystic appearance on US, there have been no studies on the outcome of PTC showing cystic contents.…”

RASSF10 is Epigenetically Inactivated and Suppresses Cell Proliferation and Induces Cell Apoptosis by Activating the p53 Signalling Pathway in Papillary Thyroid Carcinoma Cancer

“…The average age of the patients was 50.86 ± 11.85 years old, and the proportion of males was significantly less than that of females ( P < 0.05). As suggested by the World Health Organization (WHO) histological classification [27], 94 PTC patients were diagnosed with cystic papillary thyroid carcinoma (cPTC), and 14 patients were diagnosed with other types of PTC. There were 17 cases with extrathyroidal extension and 91 cases without extrathyroidal extension.…”