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The PRKD1 E710D hotspot mutation is highly specific in separating polymorphous adenocarcinoma of the palate from adenoid cystic carcinoma and pleomorphic adenoma on FNA
Author(s) -
Andreasen Simon,
Melchior Linea Cecilie,
Kiss Katalin,
Bishop Justin Avery,
Høgdall Estrid,
Grauslund Morten,
Wessel Irene,
Homøe Preben,
Agander Tina Klitmøller
Publication year - 2018
Publication title -
cancer cytopathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.29
H-Index - 57
eISSN - 1934-6638
pISSN - 1934-662X
DOI - 10.1002/cncy.21959
Subject(s) - adenoid cystic carcinoma , pleomorphic adenoma , medicine , adenocarcinoma , pathology , fine needle aspiration , carcinoma , surgical pathology , hard palate , salivary gland , cytopathology , biopsy , cancer , cytology , surgery
BACKGROUND Polymorphous adenocarcinoma (PAC) of the palatal minor salivary glands, previously known as polymorphous low‐grade adenocarcinoma, is the second most common intraoral malignant salivary gland carcinoma after adenoid cystic carcinoma (ACC) and carries an excellent prognosis. Unfortunately, PAC demonstrates cytological overlap with 2 other salivary gland tumors frequently encountered in the same location, namely ACC and pleomorphic adenoma (PA). Recently, the protein kinase D1 ( PRKD1 ) hotspot mutation E710D was demonstrated to be specific for PAC and to be present in the majority of cases. The objective of the current study was to investigate the value of PRKD1 hotspot sequencing in identifying PAC in paired fine‐needle aspiration (FNA) and surgical specimens from cases of PAC, ACC, and PA. METHODS Paired May‐Grunwald‐Giemsa‐stained FNA and corresponding surgical specimens were collected from 18 PAC cases, 25 ACC cases, and 21 PA cases. Both sets of specimens were subjected to dideoxynucleotide sequencing of PRKD1 exon 15, including the PRKD1 E710D hotspot. RESULTS Of the PAC cases, approximately 50% demonstrated identical PRKD1 E710D hotspot mutations on the FNA specimen and corresponding surgical specimen. Two ACC specimens had point mutations within the sequenced region in the FNA specimen as well as the surgical specimen, but none were located in the hotspot region. None of the PA cases demonstrated PRKD1 mutations. The specificity of the PRKD1 hotspot mutation for identifying PAC among ACC and PA cases was 100% whereas the sensitivity was 50%. CONCLUSIONS The PRKD1 E710D hotspot mutation is highly specific for identifying PAC on FNA among cases of ACC and PA, whereas the sensitivity is only modest. Alternative PRKD1 mutations exclude PAC, and are more suggestive of ACC. Cancer Cytopathol 2018;126:275‐81. © 2017 American Cancer Society.