EWSR1 rearrangement is a frequent event in papillary thyroid carcinoma and in carcinoma of the thyroid with Ewing family tumor elements (CEFTE)

• Published in: Virchows Archiv : an international journal of pathology 2017-05, Vol.470 (5), p.517-525
• Main Authors: Oliveira, G., Polónia, A., Cameselle-Teijeiro, J. M., Leitão, D., Sapia, S., Sobrinho-Simões, M., Eloy, C.
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; Carcinoma - genetics; Carcinoma - pathology; Carcinoma, Papillary; Child; Ewing sarcoma; EWSR1 rearrangement; EWSR1-FLI1; Female; Humans; Immunohistochemistry; In Situ Hybridization, Fluorescence; Male; Medicine; Medicine & Public Health; Middle Aged; Oncogene Proteins, Fusion - genetics; Original Article; Papillary thyroid carcinoma; Pathology; Real-Time Polymerase Chain Reaction; Small cell carcinoma; Thyroid; Thyroid Cancer, Papillary; Thyroid Neoplasms - genetics; Thyroid Neoplasms - pathology; Tumors; Young Adult
• ISSN: 0945-6317; 1432-2307; 1432-2307
• DOI: 10.1007/s00428-017-2095-1

Carcinomas of the thyroid with Ewing family tumor element (CEFTEs) are small-cell thyroid tumors with epithelial differentiation that disclose p63 expression and EWSR1-FLI1 rearrangement, carry a favorable prognosis and may co-exist with papillary thyroid carcinoma (PTC) foci. Two histogenetic hypotheses have been advanced regarding the origin of CEFTEs: arising in PTCs or in solid cell nests (SCN). A total of 3 CEFTEs, 54 PTCs, and 10 SCNs were reviewed, and fluorescence in situ hybridization (FISH) technique was performed in all cases to search for the presence of EWSR1 rearrangements. The three CEFTEs disclosed the EWSR1-FLI1 rearrangement both in the small cell and in the PTC component. Out of the 54 PTC cases, 28 (51.9%) were positive, 20 (37.0%) were negative, and 6 (11.1%) were inconclusive for EWSR1 rearrangement; in two of the positive PTC cases, the EWSR1-FLI1 rearrangement was detected. Classic PTC disclosed more often the EWSR1 rearrangement than other PTC variants ( p  = 0.031). PTCs with EWSR1 rearrangement disclosed a lower percentage of nuclei with EWSR1 polysomy than those without EWSR1 rearrangement ( p  = 0.001). Out of the 10 SCNs, 7 (70.0%) were negative and 3 (30.0%) were inconclusive for the EWSR1 rearrangement. Monosomic nuclei were more frequent (mean of 44.3%) in SCNs than in PTCs ( p