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Salivary glands
Primary salivary gland neoplasms - malignant
Epithelial myoepithelial carcinoma

Adriana Handra-Luca, M.D.

Topic Completed: 1 September 2012

Revised: 18 February 2020

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PubMed Search: Epithelial myoepithelial carcinoma[TI] salivary glands

Adriana Handra-Luca, M.D.
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Table of Contents
Definition / general | Clinical features | Case reports | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Positive stains | Negative stains | Electron microscopy images | Differential diagnosis
Cite this page: Handra-Luca A. Epithelial myoepithelial carcinoma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/salivaryglandsepimyocarcinoma.html. Accessed February 27th, 2020.
Definition / general
  • Rare, low grade tumor with epithelial and myoepithelial components and frequent local recurrence
  • Also called glycogen rich adenoma (clear cell pattern), myoepithelioma (spindle cell and plasmacytoid patterns), myoepithelial carcinoma (if only myoepithelial differentiation and marked cytologic atypia)
Clinical features
  • < 0.5% of salivary gland tumors
  • 80% arise in parotid gland
  • Mean age 60 years; 60% in women
  • Previously considered benign but with sufficient followup, there are rare regional nodal metastases and distant metastases to lung and kidney (Arch Pathol Lab Med 2002;126:676)
  • Recurrence related to margin status, angiolymphatic invasion, necrosis, myoepithelial anaplasia
  • In overtly malignant cases (cytologic atypia and infiltrative), metastases in 47% and 29% die of disease after mean 32 months
Case reports
Gross description
  • Well delineated, firm, infiltration into adjacent tissue
  • Usually 2 - 3 cm
Microscopic (histologic) description
  • Low grade with epithelial and myoepithelial components
  • Often multinodular with partial thick fibrous capsule
  • Most tumor cells have myoepithelial features with clear cytoplasm or naked nuclei
  • Focally, there are ducts or tubules with an outer rim of myoepithelial cells and inner, dark ductal cells with scant eosinophilic cytoplasm and round, bland nuclei
  • Also islands, nests or sheets of spindle cells, plasmacytoid (hyaline) cells
  • Often mild nuclear pleomorphism
  • May have high grade transformation / dedifferentiation: overt cytologic malignancy, infiltrative growth and perineurial invasion (Am J Surg Pathol 2010;34:1258)
  • Variable mitotic activity; may have ancient change, sebaceous features, Verocay-like change
  • Variants include apocrine, dedifferentiated, double clear, ex pleomorphic adenoma, oncocytic (senescence phenotype), with myoepithelial anaplasia (myoepithelial overgrowth, Arch Pathol Lab Med 2009;133:950)
  • Dedifferentiated variant: undifferentiated carcinoma of clear cell, spindle cell, squamous cell type; atypia in > 20% cells, no myoepithelial differentiation, older patients, more aggressive behavior, extraglandular and metastastic extension
Microscopic (histologic) images

Case of the Week #54
   

Various images

AE1 / AE3

S100



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Oncocytic-sebaceous and apocrine

Cytology description
  • Cellular, with single cells and naked nuclei
  • Biphasic pattern may not be evident since clear cells have fragile cytoplasm and often appear as naked nuclei (Diagn Cytopathol 2003;28:163)
Positive stains
Negative stains
Electron microscopy images

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Oncocytic-sebaceous and apocrine variants

Differential diagnosis
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