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PRELIMINARY CYTOLOGIC DIAGNOSIS: Suspicious for Acinic Cell Carcinoma. Cell Block: Immunohistochemical Studies GCDFP-15 S-100 CYTOLOGIC DIAGNOSIS: Consistent with mammary analogue secretory carcinoma. Mammoglobin Clinical Management: Superficial parotidectomy: Note: Additional testing revealed an ETV6-NTRK6 rearrangement using targeted RNA-Seq by next generation sequencing confirming the diagnosis of MASC. 2
Final Diagnosis: First described by Skalova et al in 2010 Similar to secretory carcinoma of breast Previously classified as acinic cell carcinoma or adenocarcinoma, NOS Absence of true serous-type acinar differentiation T(12;15)(p13;q25) ETV6-NTRK3 translocation Average age: 4 th -5 th decade M>F Parotid gland is most common site Low grade biologic behavior Increased lymph node metastasis relative to acinic cell carcinoma in some cases FNA of FNA of Cytologic Reports of MASC: Levine et al.: 1 case Griffith et al.: 6 cases Bishop et al.: 5 cases Pisharodi: 1 case Cytologic Features: Single cells and papillary groups Abundant vacuolated cytoplasm without zymogen granules Eosinophilic rather than basophilic cytoplasm Uniform round nuclei Intra- and extracellular mucin Scant or absent mitoses 3
FNA of FNA of : Dispersed population of low N/C cells Vacuolated cells in a secretory background Multiple small cytoplasmic vacuoles Background seromucinous material FNA of : Round eccentric nucleus with small distinct nucleolus Immunohistochemical Profile: S-100+ Mammaglobin + Muc4+ GCDFP-15 + Androgen receptor P63 focal+ 4
ETV6-NKRT Translocation: T(12:15)(p13;q25) MASC is only known salivary gland primary Detected on histology or cytology using: FISH RT-PCR Next-Gen Sequencing Salivary Gland FNA and Increasing Availability of Molecular Markers MASC: ETV6-NKRT Translocation Mucoepidermoid carcinoma: t(11:19) MECT1/MAML2 74% of LG cases Adenoid Cystic Carcinoma: T(6:9) MYB-NFIB transcription factor Present in 50-80% SALIVARY GLAND FNA Salivary gland tumors are one of the most heterogeneous groups of neoplasms So what role is there for FNA? Rationale for FNA: Guide the clinical management/pre-op strategy:»non-neoplasticneoplastic»benign tumor or low-grade carcinoma»high-grade grade carcinoma SALIVARY GLAND FNA: How Far Can We Go? Usually Specific Diagnosis Sometimes Specific Diagnosis Usually Descriptive Diagnosis CLASSIC PLEOMORPHIC ADENOMA: Greater than 95% accuracy by FNA Pleomorphic adenoma Adenoid cystic carcinoma Basal cell adenoma, tubulotrabecular and solid types Warthin tumor LG mucoepidermoid carcinoma HG mucoepidermoid carcinoma Basal cell adenoma, Membranous type Metastasis Polymorphous low grade adenocarcinoma Acute and chronic sialadenitis Carcinoma ex PA Salivary duct carcinoma Reactive lymph node Small cell carcinoma Basal cell adenocarcinoma Lymphoma Mucocele Epithelial-myoepithelial carcinoma Oncocytoma LESA Acinic cell carcinoma 5
Warthin Tumor: Easily recognized by combination of oncocytes, lymphocytes, and debris Classic Adenoid Cystic Carcinoma Low Grade Mucoepidermoid Carcinoma: Often hypocellular with bland epidermoid cells Solid Basal Cell Adenoma vs Solid Adenoid Cystic Carcinoma Basal cell adenoma Adenoid cystic carcinoma Acinic cell carcinoma with dispersed cells Cytologic DDX of MASC Acinic cell carcinoma Oncocytoma Mucoepidermoid carcinoma (oncocytic variant) Metastatic carcinoma Benign salivary gland 6
Acinic cell carcinoma with low N:C ratio cells, basophilic cytoplasm, and cytoplasmic vacuoles FNA of Oncocytoma: Dense, non-vacuolated cytoplasm MASC is distinguished by immunoprofile and Unique ETV6 rearrangement. FNA of Mucoepidermoid Carcinoma: Epidermoid cells lacking the delicate vacuolated cytoplasm of MASC FNA of Salivary Duct Carcinoma: Eosinophilic and markedly atypical FNA of Low Grade Mucoepidermoid Carcinoma: Goblet-type mucocytes are not characteristic of MASC Summary: Rare tumor distinct from acinic cell carcinoma Defined by absence of zymogen granules, immunoprofile, and by ETV6-NKRT translocation May have a slightly more aggressive clinical behavior than acinic cell carcinoma 7
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