Clinicopathologic Features and Cytologic Correlation of ALK-Rearranged Papillary Thyroid Carcinoma: A Series of Eight Cases.
Endocr Pathol
; 35(2): 134-146, 2024 Jun.
Article
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| MEDLINE
| ID: mdl-38642308
ABSTRACT
Anaplastic lymphoma kinase (ALK) gene fusions are rare in papillary thyroid carcinoma (PTC) but may serve as a therapeutic target. This study aims to evaluate the preoperative cytologic findings and clinicopathologic features of a series of eight ALK-rearranged PTCs from our pathology archives and consultations. All cases were confirmed by ALK D5F3 immunohistochemistry and six with additional targeted RNA-based next-generation sequencing (NGS). The original fine-needle aspiration (FNA) cytology diagnosis included the Bethesda System (TBS) category II in three (37.5%), TBS III in two (25%), TBS V in two (25%), and TBS VI in one (12.5%). Six cases had available FNA cytology and were reviewed. The cytologic features showed microfollicular architecture as well as limited or reduced nuclear elongation and chromatin alterations in all six. Nuclear grooves and pseudoinclusions were absent in two cases, rarely or focally noted in three, and frequently found in one. Two cases initially diagnosed as TBS II, showing microfollicular architecture without well-developed nuclear features, were revised to TBS III (with architectural atypia only). For histologic correlations, four were infiltrative follicular variant PTCs, three as classic subtype PTC with predominant follicular growth, and one as solid/trabecular subtype PTC. All eight cases demonstrated reduced PTC nuclear features with respect to nuclear elongation and chromatin alterations compared to those typically identified in "BRAF-like" PTCs. The NGS testing revealed EML4ALK fusion in three, STRNALK fusion in two, and ITSN2ALK fusion in one. In conclusion, although ALK-rearranged PTCs have been associated with neutral gene expression profile from a BRAF-RAS scoring perspective, the "RAS-like" nuclear features were more commonly identified in this series, resulting in frequent indeterminate diagnosis of preoperative FNA.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Neoplasias de la Tiroides
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Reordenamiento Génico
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Cáncer Papilar Tiroideo
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Quinasa de Linfoma Anaplásico
Límite:
Adult
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Aged
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Female
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Humans
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Male
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Middle aged
Idioma:
En
Revista:
Endocr Pathol
Asunto de la revista:
ENDOCRINOLOGIA
/
PATOLOGIA
Año:
2024
Tipo del documento:
Article
País de afiliación:
Taiwán
Pais de publicación:
Estados Unidos