Salivary glands
Primary salivary gland neoplasms
Benign
Myoepithelioma
Author: Adriana Handra-Luca, M.D.
Topic Completed: 1 September 2012
Minor changes: 13 April 2021
Copyright: 2003-2021, PathologyOutlines.com, Inc.
PubMed Search: Myoepithelioma[TI] salivary glands
Table of Contents
Definition / general | Clinical features | Case reports | Clinical images | Gross description | Microscopic (histologic) description | Microscopic (histologic) images | Cytology description | Positive stains | Negative stains | Molecular / cytogenetics description | Differential diagnosisCite this page: Handra-Luca A. Myoepithelioma. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/salivaryglandsmyoepithelioma.html. Accessed April 15th, 2021.
Definition / general
- Rare benign tumor composed only of myoepithelial cells
- Formerly considered a variant of pleomorphic adenoma
- See also epithelial myoepithelial carcinoma
Clinical features
- 1% of salivary gland tumors, more common in parotid and minor salivary gland tumors
- Mean age 54 years, also children
- May be associated with myasthenia gravis
- Recur locally if incomplete removal
- Imaging: well circumscribed, lobulated, inhomogeneous enhancement, apparent diffusion coeficient on MRI different from Warthin tumor and similar to pleomorphic adenoma (AJNR Am J Neuroradiol 2009;30:591)
Case reports
- 29 year old woman with plasmacytoid myoepithelioma of palate (Head Neck Pathol 2011;5:154)
- 80 year old man with cystic clear cell myoepithelioma of parotid gland (Oral Maxillofac Surg 2009;13:45)
Clinical images
Images hosted on other servers:
Plasmacytoid myoepithelioma of minor salivary glands
Gross description
- Up to 5 cm; encapsulated, may have cystic change
Microscopic (histologic) description
- Solid (nonmyxoid), myxoid (pleomorphic adenoma-like), reticular (canalicular-like) or mixed patterns of myoepithelial cells with no ductal differentiation
- Plasmacytoid cells, spindle cells, clear cells, epithelioid cells, oncocytic cells, hyaline cells
- Mucoid or hyaline stroma, rarely lipomatous
- Rarely synchronous with adenoid cystic carcinoma
- Rarely with intracapsular invasion
Microscopic (histologic) images
Images hosted on other servers:
Plasmacytoid myoepithelioma of palate
Plasmacytoid myoepithelioma of minor salivary glands
Myoepithelioma of minor salivary gland of cheek
Cytology description
- Nuclear grooves, intranuclear cytoplasmic inclusions, nuclear striations (zebra lines), myxoid matrix; no marked pleiomorphism, no mitoses
Positive stains
- Vimentin, GFAP, S100, calponin (Braz Dent J 2007;18:192), HHF35, CD10, cytokeratin 5 / 6, CK7, CK14, CEA (variable)
- Also muscle specific actin
Molecular / cytogenetics description
- Aneuploid or diploid, 12q alterations, chromosome 8q involved in malignant phenotype
Differential diagnosis
- Epidermal cyst: similar clinically
- Squamous cell carcinoma
- Undifferentiated carcinoma
- Warthin tumor: similar on ultrasound
