A 52-year-old woman presents with a firm, fixed submandibular gland mass of 3 months duration. She has noted tingling along the lower lip on the same side. FNAC confirms adenoid cystic carcinoma. Which feature best explains the lip numbness and is the hallmark biological behavior of this tumor?
- A Perineural spread along the inferior alveolar nerve ✓
- B Lymphatic permeation causing regional node enlargement
- C Hematogenous dissemination to the mandible
- D Direct invasion of the mylohyoid muscle
Correct answer: A. Perineural spread along the inferior alveolar nerve
Explanation
Adenoid cystic carcinoma characteristically shows perineural invasion, often presenting early with neuropathic symptoms such as numbness or pain along the affected nerve distribution. Involvement of the inferior alveolar nerve explains the lower lip paresthesia. Lymphatic spread is less common in adenoid cystic carcinoma compared to other salivary malignancies, and bone metastasis is a late feature rather than the cause of early lip numbness.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.