Foster Kennedy syndrome is caused by a tumor in which lobe of the brain?

• A. Frontal lobe
• B. Parietal lobe
• C. Temporal lobe
• D. Occipital lobe

Answer: (A)

This pattern comes from a tumor in the frontal lobe near the olfactory tract, classically an olfactory groove meningioma. The lesion presses on the ipsilateral optic nerve, causing optic atrophy in that eye, while raised intracranial pressure from the mass leads to papilledema in the opposite eye. It also damages the olfactory pathways, producing loss of smell. Because this triad stems from a lesion at the base of the frontal lobe, a frontal lobe location explains the combination of optic atrophy, contralateral papilledema, and anosmia. Tumors in the parietal, temporal, or occipital lobes don’t typically produce this specific olfactory-plus-vision pattern.