Successful osimertinib treatment for Meckel's cave metastasis: a case report.

Osimertinib has emerged as the standard first-line treatment for advanced non-small cell lung cancer (NSCLC) with EGFR mutations, offering improved tolerability and demonstrating superior efficacy against brain metastases in comparison with other tyrosine kinase inhibitors. The Meckel's cave is a dural recess in the posteromedial part of the middle cranial fossa that acts as a conduit for the trigeminal nerve between the anterior pontine cisterna and the cavernous sinus, and houses the Gasserian ganglion and proximal radicle of the trigeminal nerve. Trigeminal neuropathy, characterized by numbness and dysesthesia of the skin and mucous membranes of the face, poses diagnostic challenges and often requires differentiation from conditions, such as compression neuropathy, inflammation, and drug-induced reactions. Here, we report the case of Meckel's cave metastasis. She presented headache, anorexia, left facial numbness, and pain indicative of trigeminal neuropathy. Imaging revealed metastasis to Meckel's cave, consistent with her clinical symptoms. EGFR L858R mutation was detected by primary lesion of the lung DNA analysis. Treatment with osimertinib led to regression of the primary tumor and improvement of the trigeminal neuropathy within 3 months. Importantly, our review of the relevant literature identified only two similar cases with metastasis of lung adenocarcinoma to Meckel's cave. Ours was the only case in which symptom resolution was achieved. We underscore the utility of MRI and PET/CT studies in evaluating trigeminal-related symptoms and discuss imaging characteristics that may aid in their differentiation.