A 55-year-old woman presents with progressive unilateral sensorineural hearing loss and tinnitus. MRI reveals a well-circumscribed, enhancing cerebellopontine angle mass extending into the internal auditory canal. Histology shows a biphasic tumor with Antoni A areas, Verocay bodies, and Antoni B areas. Which chromosome harbors the gene responsible for this tumor's pathogenesis?

• A Chromosome 22 (NF2 gene) ✓
• B Chromosome 17 (NF1 gene)
• C Chromosome 9 (TSC1 gene)
• D Chromosome 16 (TSC2 gene)

Explanation

The clinical and histological features describe vestibular schwannoma, a benign nerve sheath tumor arising from Schwann cells of the vestibular division of CN VIII. Schwannomas are associated with neurofibromatosis type 2 (NF2), caused by mutations in the NF2 gene on chromosome 22q12 encoding merlin. NF1 on chromosome 17 causes neurofibromatosis type 1, associated with neurofibromas, not schwannomas. TSC1 and TSC2 are linked to tuberous sclerosis.

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.