title: Salivary duct carcinoma: the predominance of apocrine morphology, prevalence of histologic variants, and androgen receptor expression.
abstract: Salivary duct carcinoma (SDC) is a prototypic aggressive salivary gland carcinoma. Our aim is to determine the prevalence of histologic variants (micropapillary, basal-like) and androgen receptor (AR) expression in a large multi-institutional series of SDC. AR status was determined by immunohistochemistry (IHC). Most SDCs were characterized by an apocrine phenotype and AR expression. Cases with a nonapocrine phenotype and AR-negative status were studied by additional IHC and fluorescence in situ hybridization for ETV6 or MYB/NFIB. The diagnosis of SDC was confirmed in 187 of 199 (94%) cases. Variant morphologies were identified in 12 cases: micropapillary (n=6), sarcomatoid (n=3), mucinous (n=2), and basal-like (n=1). AR IHC was performed in 183 cases, of which 179 (97.8%) showed AR expression. On the basis of morphologic appearance and results of additional studies, 12 cases were reclassified as squamous cell carcinoma (SCC) (n=4), epithelial-myoepithelial carcinoma with high-grade transformation (HGT) (n=2), myoepithelial carcinoma (n=2), mammary analogue secretory carcinoma, high grade (ETV6 translocated; n=1), adenoid cystic carcinoma with HGT (n=1), acinic cell carcinoma with HGT (n=1), and adenosquamous carcinoma (n=1). AR-negative SDC is extremely rare, and the majority of such cases are more accurately classified as other entities. HGTs of other salivary carcinomas and squamous cell carcinoma are the most common mimics of SDC. SDCs with variant morphologies still show at least a minor component of conventional apocrine appearance. Thus, apocrine morphology defines SDC.
authors: *University of Pittsburgh Medical Center, Pittsburgh ∥Department of Pathology, Thomas Jefferson University, Philadelphia, PA †Southern California Permanente Medical Group, Woodland Hills, CA §Virginia Mason Medical Center, Seattle, WA ‡University Health Network, Toronto #Department of Pathology, University of Ottawa, Ottawa, ON, Canada ¶Aga Khan University Hospital, Karachi, Pakistan.
authors: Lindsay
authors: L
authors: Williams
authors: Lester D R
authors: LD
authors: Thompson
authors: Raja R
authors: RR
authors: Seethala
authors: Ilan
authors: I
authors: Weinreb
authors: Adel M
authors: AM
authors: Assaad
authors: Madalina
authors: M
authors: Tuluc
authors: Nasir
authors: N
authors: Ud Din
authors: Bibianna
authors: B
authors: Purgina
authors: Chi
authors: C
authors: Lai
authors: Christopher C
authors: CC
authors: Griffith
authors: Simion I
authors: SI
authors: Chiosea
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D008875:Middle Aged; D011944:Receptors, Androgen / Q000032:analysis / Q000096:biosynthesis*; D012468:Salivary Gland Neoplasms / Q000378:metabolism / Q000473:pathology*
chemical_list: C410798:AR protein, human; D014408:Biomarkers, Tumor; D011944:Receptors, Androgen