Pathology · patient case with 1 question
Facial weakness with a mass in the region of the mandibular ramus
Patient: Male, 57 years old
Chief Complaint: “The right side of my face has been drooping for about two months.”
Background: No preceding viral illness, no ear pain, no vesicles, no fever. The weakness came on gradually and has worsened. Former smoker.
Vital Signs: BP 134/82 mmHg · HR 76 bpm · T 98.2°F
Findings: Drooping of the right lower face with loss of the nasolabial fold. Eye closure and forehead wrinkling are PRESERVED on the affected side. A firm, non-tender, slowly enlarging swelling overlies the posterior region of the right mandibular ramus. No trismus, no skin erythema, no lymphadenopathy detected, no dental source identified.
Question 1
What is the most likely underlying cause of this presentation?
Show answer and explanation
Correct answer: B. A neoplastic process
- A. An odontogenic infection produces pain, erythema, warmth, swelling, trismus, fever and an identifiable dental source. None is present, and infection does not cause a progressive facial palsy over two months.
- B. CORRECT. Three features converge on NEOPLASIA. The onset is GRADUAL AND PROGRESSIVE over two months, whereas Bell palsy and Ramsay Hunt reach maximum weakness within 72 hours. There is a FIRM, PAINLESS, ENLARGING MASS in the parotid region overlying the ramus, and progressive facial nerve weakness in the presence of a parotid mass is a malignant tumour until proven otherwise — benign parotid tumours characteristically spare the nerve. And the weakness is PARTIAL, affecting only some branches, which is the pattern of a mass compressing or infiltrating specific divisions rather than a global palsy of the trunk.
- C. An inflammatory reaction would be painful and self-limiting, and would not produce a firm enlarging mass with progressive nerve deficit.
- D. A viral cranial neuropathy — Bell palsy or Ramsay Hunt — is ACUTE, peaks within days, involves the WHOLE side including eye closure, and comes with no mass. Ramsay Hunt adds ear pain and vesicles. The tempo alone excludes it.
Note: ⚠️ Read the eye-closure finding carefully, because it cuts two ways. PRESERVED forehead and eye closure with lower-face weakness is the classic signature of an UPPER motor neuron lesion — a stroke — since the frontalis receives bilateral cortical input. But it is also what a mass produces when it compresses only the LOWER divisions of the nerve after the trunk has branched within the parotid. The mass is what decides it here. Any patient with a parotid mass AND facial nerve weakness needs urgent imaging and referral.