Salivary gland FNA: New markers and new opportunities for improved diagnosis

Abstract

Salivary gland fine‐needle aspiration represents one of the most challenging areas of cytopathology; however, the discovery of several novel and/or next‐generation immunocytochemical and molecular markers for salivary gland tumors has resulted in greater diagnostic accuracy in cytologic diagnosis. In this commentary, recent advances in salivary gland cytopathology are reviewed with a focus on salivary gland tumors associated with gene rearrangements.

The PRKD1 E710D hotspot mutation is highly specific in separating polymorphous adenocarcinoma of the palate from adenoid cystic carcinoma and pleomorphic adenoma on FNA

“…Although this aids in diagnosing macroscopic specimens as well as small incisional biopsies, this finding is not readily transferrable to the cytological setting, especially in cases in which few slides are available or only a few tumor cells are present on each slide. In the same way, due to the limited amount of material, immunocytochemical panels are not easily applied …”

PLAG1: An Immunohistochemical Marker with Limited Utility in Separating Pleomorphic Adenoma from Other Basaloid Salivary Gland Tumors

“…It gives time for consensus opinion and ancillary studies where needed. Hence, the study and evaluation of ancillary tests in FNAs is immensely useful [8,9]. The challenge of diagnosis in FNAs of salivary gland masses is compounded by the fact that the morphology of the lesions is not only extensively diverse, but also significantly overlapping.…”

“…The transcriptional upregulation of PLAG1 leads to a high level of protein expression in PAs with PLAG1 rearrangements [4,5]. A few studies have analyzed the utility of PLAG1 in salivary gland neoplasms [6,7,8], but these have mostly been on surgical excision (SE) specimens. FNA materials present a diagnostically unique challenge because of the limited material on which the diagnosis is made.…”

The role of the Milan System for Reporting Salivary Gland Cytopathology: A 5‐year institutional experience

“…The technique is minimally invasive and well tolerated by patients without significant complications, and is a cost‐effective diagnostic tool with a high sensitivity and specificity of approximately 54% to 98% and 88% to 98%, respectively . FNA plays a key role in guiding clinical management and provides useful information such as distinguishing between a neoplastic and a non‐neoplastic lesion, ascertaining whether a lesion is benign or malignant, and, last, providing prognostic information and a sample for ancillary testing such as molecular studies …”