A 65-year-old woman presents with a painless right parotid swelling that has been slowly enlarging for 8 years. Recent rapid growth and facial nerve weakness suggest malignant transformation. Fine-needle aspiration cytology shows carcinoma ex pleomorphic adenoma. The MOST important prognostic factor determining survival is:
- A Patient age at diagnosis
- B Extent of invasive component (non-invasive/minimally invasive vs widely invasive) ✓
- C Duration of the benign phase
- D Involvement of facial nerve
Correct answer: B. Extent of invasive component (non-invasive/minimally invasive vs widely invasive)
Explanation
In carcinoma ex pleomorphic adenoma, the single most important prognostic factor is the extent of the invasive (malignant) component. Non-invasive (intracapsular) and minimally invasive (<1.5 mm beyond capsule) forms carry excellent prognosis, while widely invasive disease has markedly worse survival. Facial nerve involvement affects surgical planning but the invasion extent determines prognosis. Patient age and duration of benign phase are secondary factors.
Reference: Dhingra Diseases of Ear, Nose and Throat, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.