Oncocytic intraductal carcinoma of salivary glands: a distinct variant with TRIM33–RET fusions and BRAF V600E mutations

• DOI: 10.1111/his.14296
• Publication Date: 2020-11-02T04:52:56Z
• Authors: Justin A Bishop; Masato Nakaguro; Rumeal D Whaley; Kanako Ogura; Hiroshi Imai; Israa Laklouk; William C Faquin; Peter M Sadow; Jeffrey Gagan; Toshitaka Nagao
• Keywords: Mammaglobin; Apocrine; Hidradenoma; Salivary duct carcinoma

Salivary gland intraductal carcinoma (IDC) is a complex ductal neoplasm surrounded by layer of myoepithelial cells. Recent insights have shown that there are three different types: intercalated duct-like, with frequent NCOA4-RET fusions; apocrine, salivary duct carcinoma-like mutations; and mixed duct-like/apocrine, RET fusions, including TRIM27-RET. In addition, an oncocytic IDC has been described, but it remains unclear whether represents fourth variant or simply metaplasia another type. Our aim was to more completely characterize IDC.Six IDCs changes were retrieved from the authors' archives, men women ranging in age 45 75 years (mean, 63 years). Five arose parotid gland, one accessory gland. Four patients follow-up free disease after 1-23 months. Several immunostains (S100, mammaglobin, androgen receptor, p63/p40) molecular tools (RNA sequencing, fluorescence in-situ hybridisation, BRAF V600E VE1 immunohistochemistry, Sanger sequencing) applied. Histologically, tumours variably cystic solid intracystic nodules often difficult recognise as intraductal. all, tumour ducts positive for S100 negative cells p63/p40. Molecular analysis revealed TRIM33-RET two six cases, cases. One case had no identifiable alterations.Oncocytic shares similarities duct-like IDC. Although additional verification needed, appears be sufficiently unique now regarded distinct subtype Because its indolent nature, should distinguished histological mimics.