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Relevance of rosette patterns in variants of papillary thyroid carcinoma
Author(s) -
Dell'Aquila Marco,
Musarra Teresa,
Fiorentino Vincenzo,
Brunelli Chiara,
De Marco Costanza,
Raffaelli Marco,
Traini Emanuela,
Pio Lombardi Celestino,
Fadda Guido,
Larocca Luigi Maria,
Pantanowitz Liron,
Rossi Esther Diana
Publication year - 2020
Publication title -
cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.512
H-Index - 48
eISSN - 1365-2303
pISSN - 0956-5507
DOI - 10.1111/cyt.12885
Subject(s) - thyroid carcinoma , malignancy , medicine , pathology , cytopathology , thyroid , fine needle aspiration , cytology , thyroid nodules , biopsy
The detection of rosette‐like clusters (RLC) of follicular cells in thyroid carcinoma has been reported mostly in the columnar cell variant of papillary thyroid carcinoma (PTC). Despite the fact that diagnosing variants of PTC is no longer encouraged by The Bethesda System for Reporting Thyroid Cytopathology, the identification of cytomorphological features such as RLC linked with these tumours might help reduce possible misinterpretation in thyroid fine needle aspiration (FNA) cytology. We accordingly investigated the potential correlation of architectural patterns including RLC with PTC variants. Methods We analysed 225 thyroid FNA cytology cases diagnosed as suspicious for malignancy (SFM) and positive for malignancy (M) over a 1‐year time where all samples had corresponding histology. We also included 150 benign lesions from the same period. The presence of RLC vs similar appearing solid clusters, papillary structures and microfollicles were evaluated. We also performed immunocytochemistry and molecular testing for BRAFV600E . Results We included 100 (44.4%) SFM favouring PTC and 125 (55.6%) M cases with cyto‐histological correlation. On histology, all SFM and M cases showed malignancy including 140 (62.2%) classic PTC and 85 (37.8%) PTC variants. The cytomorphological patterns in all FNA samples included solid (74%), papillary (89%), microfollicular (70%), and pseudo‐RLC morphology (25.7%). We identified only pseudo‐RLC in 33 FNA specimens from PTC variant cases that included tall cell variant (42.4%), hobnail variant (21.2%) and miscellaneous variants (36.3%) of PTC. No definitive RLC were detected in our series. Immunocytochemistry and BRAFV600E were not specifically linked with an RLC pattern. Conclusions These findings demonstrate that in our dataset the architectural pattern of RLC was not recognised within PTC variants. However, we did identify a pseudo‐RLC pattern that was observed in association with tall cell variant and hobnail variant cases of PTC.