AtlasSalivaryPleomorphic Adenoma

Salivary Gland Disorders

Pleomorphic Adenoma

aka PA · Benign Mixed Tumour

Commonest benign salivary gland tumour; slow-growing painless mass composed of epithelial, myoepithelial and mesenchymal-like elements; recurrence risk if incompletely excised or capsule breached.

Site
Parotid superficial lobe
Rx
Superficial parotidectomy
Malignant risk
~6% long-standing

§ overviewOverview

Benign salivary gland neoplasm composed of variable mixtures of epithelial and myoepithelial cells within a chondromyxoid stroma.

§ icdICD Classification

D11

§ etiologyEtiology

  • 01PLAG1 or HMGA2 gene rearrangements in most cases

§ epidemiologyEpidemiology

≈60% of all salivary tumours; parotid (85%, especially superficial lobe) > minor glands (palate) > submandibular; F > M, ages 30–50.

§ clinicalClinical Features

  • 01Painless, slow-growing, mobile, firm swelling
  • 02Parotid: preauricular mass without facial nerve involvement
  • 03Palatal: firm submucosal swelling posterolateral hard palate
  • 04Long history (years)

§ differentialDifferential Diagnosis

  • 01Warthin tumour (bilateral, older males, smokers)
  • 02Mucoepidermoid carcinoma
  • 03Adenoid cystic carcinoma
  • 04Lymph node
  • 05Lipoma

§ histopathHistopathology

  • 01Biphasic: epithelial (ducts, sheets) + myoepithelial (spindle, plasmacytoid) cells
  • 02Chondromyxoid or hyaline stroma
  • 03Pseudocapsule with microscopic tumour extensions (pseudopodia)

§ investigationsInvestigations

  • 01USG-guided FNAC (85–90% accurate)
  • 02MRI (T2 hyperintense with capsule)
  • 03Core biopsy avoided in parotid (seeding risk)

§ ihcIHC / Special Stains

  • 01Epithelial: CK+; myoepithelial: S-100, GFAP, p63, calponin, SMA

§ treatmentTreatment

  • 01Parotid: superficial parotidectomy with facial nerve preservation (deep lobe → total parotidectomy)
  • 02Submandibular: gland excision
  • 03Palate/minor gland: wide local excision including periosteum/bone
  • 04Enucleation → 25–45% recurrence — obsolete

§ complicationsComplications

  • 01Recurrence (multinodular)
  • 02Facial nerve injury
  • 03Frey syndrome (gustatory sweating)
  • 04Carcinoma ex pleomorphic adenoma (malignant transformation ≈ 6% in long-standing PA)

§ prognosisPrognosis

Excellent with appropriate surgery; recurrence risk correlates with capsular disruption at first operation.

§ examKey Examination Points

  • 01Palpable, mobile, painless mass without facial nerve palsy
  • 02Enucleation is inadequate

§ revisionQuick Revision Summary

  • 01Commonest salivary tumour · superficial parotidectomy · avoid enucleation · beware carcinoma ex PA

§ vivaBDS Viva Questions

  • 01Why not enucleate?
  • 02Facial nerve anatomy at parotid surgery?
  • 03Signs of malignant transformation?

§ mcqsMCQs — Assessment (3)

Question 1

Commonest site:

Question 2

Recommended operation for parotid PA:

Question 3

Feature suggesting carcinoma ex PA:

References

  1. WHO Head & Neck Tumours 2022

Draft — pending faculty review. Educational use only; verify against current guidelines and primary sources before clinical application.