Ancillary testing strategies in salivary gland aspiration cytology: A practical pattern‐based approach

Abstract

Fine needle aspiration of salivary gland tumors is a common preoperative triage as it is useful in determining which patients should undergo surgical resection and in guiding the extent of surgery in those cases deemed appropriate for resection. While a specific diagnosis can be achieved on a cytologic specimen in many cases, there is also a considerable amount of morphologic diversity that prevents such confident preoperative classification and in these cases it can be a challenge to confidently determine if a tumor is benign or malignant. Recently, a pattern based risk stratification approach was proposed for salivary gland cytology in which basaloid neoplasms are separated by stromal characteristics and oncocytoid neoplasms are separated primarily by background material such as mucus. In addition to potentially providing a stratification in risk of malignancy for salivary gland tumors, this approach is also useful to narrow differential diagnostic considerations and guide ancillary testing. In this review we use this proposed pattern based approach as a framework to discuss immunostains and fluorescence in situ hybridization studies which we find useful in our practice.

Subtyping salivary gland neoplasm of uncertain malignant potential based on cell type demonstrates differential risk of malignancy

“…Recent molecular advances reveal several type‐specific genetic alterations in salivary gland tumors . Ancillary testing, such as immunocytochemistry, fluorescence in situ hybridization, or polymerase chain reaction, has emerged and has been used increasingly in cytopathology . Nonetheless, more studies are still required to validate the performance of these tests on cytologic specimens.…”

Diagnostic challenges and problem cases in salivary gland cytology: A 20‐year experience

“…Abundant fibrillary or chondromyxoid matrix along with epithelial and myoepithelial cells are reported in 90% of cases . p63/p40, S‐100, PLAG1, SRY‐Box 10 (SOX10), myoepithelial markers (smooth muscle actin [SMA], calponin) and glial fibrillary acidic protein are immunoreactive in PA whereas myb domain protein 1 (MYB1) is negative . Typically, paucicellularity of the sample with an abundant stromal component does not cause any difficulty in diagnosis .…”

“…CK7, CK8, CK19, and p63 are positive in most mucoepidermoid carcinoma cases whereas calponin is positive in a small percentage (10%) of cases and SMA, S‐100, mammaglobin, and SOX10 are negative. Warthin tumor and mucoepidermoid carcinoma both are immunoreactive for p63 and p40 . Furthermore, Warthin tumor is positive for c‐kit (CD‐117) and mucoepidermoid carcinoma is negative .…”

“…A diagnosis of high‐grade salivary gland malignancy is sufficient for proper clinical management when it is impossible to differentiate these entities . Salivary duct carcinoma is immunoreactive for androgen receptor stain and mammaglobin is positive in some of the cases …”

“…6 p63/p40, S-100, PLAG1, SRY-Box 10 (SOX10), myoepithelial markers (smooth muscle actin [SMA], calponin) and glial fibrillary acidic protein are immunoreactive in PA whereas myb domain protein 1 (MYB1) is negative. 7,8 Typically, paucicellularity of the sample with an abundant stromal component does not cause any difficulty in diagnosis. 5 However, scarcity of matrix material with a dominant epithelioid or myoepithelial cell component can lead to misdiagnoses such as adenocarcinoma and myoepithelioma.…”