Salivary glands
Epithelial / myoepithelial tumors
General

Author: F. Zahra Aly, M.D., Ph.D. (see Authors page)

Revised: 13 March 2018, last major update August 2011

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Salivary[TI] epithelial myoepithelial tumors[mh]

Cite this page: Aly, F.Z. Epithelial / myoepithelial tumors - general. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/salivaryglandstumorsgeneral.html. Accessed July 21st, 2018.
Definition / general
  • Risk factors: radiation exposure (atomic bomb survivors, radiation therapy, chemoradiation therapy) with mean latency after low dose radiation exposure of 11 years for malignant tumors and 21 years for benign tumors
    • Alcohol and tobacco are NOT risk factors except for Warthin tumor (associated with smoking)
  • Benign: pleomorphic adenoma (50%), Warthin tumor (5%), oncocytoma, basal cell adenoma, ductal papilloma
  • Malignant: mucoepidermoid carcinoma (15%), polymorphous low grade adenocarcinoma (10%), acinic cell carcinoma, adenoid cystic carcinoma, malignant mixed tumor, squamous cell carcinoma (1%)
  • Bilateral tumors: Warthin tumor is most common, also pleomorphic adenoma and acinic cell carcinoma
  • 15% of parotid tumors are malignant, 40% elsewhere
  • Children: pleomorphic adenoma most common but more often malignant; most common malignant tumors are mucoepidermoid carcinoma, adenoid cystic carcinoma, acinic cell carcinoma
  • Regional lymph nodes: nodal metastases usually evident on initial clinical evaluation
    • Low grade tumors rarely metastasize to regional nodes, high grade tumors often do; nodal involvement tends to be orderly from intraglandular to adjacent nodes to upper and midjugular nodes and occasionally to retropharyngeal nodes
    • Bilateral nodal involvement is rare
  • Metastases: usually to lungs
Sites
  • > 90% arise in parotid gland, 5% in submandibular gland
  • Deep parotid tumors may present as intraoral masses
  • Sublingual tumors are rare and may be difficult to distinguish from minor salivary gland primary tumors of anterior floor of mouth
  • Minor salivary gland tumors usually in hard palate (site with most glandular tissue); may arise in lymph nodes around salivary glands
Poor prognostic factors
  • Postoperative recurrence, submandibular gland site, facial nerve paralysis, high grade tumor
Treatment
  • Parotid gland tumors: superficial lobe tumors are treated with superficial / partial parotidectomy with preservation of facial nerve
    • Total parotidectomy with sacrifice of facial nerve may be necessary if high grade or advanced tumor
    • Neck dissection necessary if nodal involvement
  • Submandibular tumors: total excision; often recur because of difficulty of getting good margins due to closeness of mandible
  • Radiation therapy: for inoperable tumors