NIMG-31. CASE REPORT: DIAGNOSIS OF AN INFILTRATIVE GLIOMA IN A LI-FRAUMENI SYNDROME PATIENT OBSCURED BY LESION RESPONSIVENESS TO NSCLC TREATMENT

Abstract Li-Fraumeni syndrome is a rare, autosomal dominant disorder linked to germline mutations of the TP53 suppressor gene. Patients with this syndrome are predisposed to various malignancies and a variety of brain tumors to include choroid plexus carcinoma, medulloblastoma, and glioma. We present a 46-year-old woman with a history of Li-Fraumeni syndrome which manifested with multiple systemic malignancies including breast cancer, ovarian teratoma, and leiomyosarcoma. The patient had been undergoing MRI brain surveillance since 2018, which was initially notable for a right cerebellar midline focus of enhancement associated with slowly evolving right middle cerebellar peduncle FLAIR signal, with no detectable neurologic symptoms. She underwent systemic therapy for non-small cell lung cancer (NSCLC) with pemetrexed/cisplatin. Her next MRI brain in August 2023 showed resolution of the cerebellar enhancement with small residual FLAIR signal. In April 2024, the patient presented with new neurologic symptoms to include ataxia, dizziness, difficulty swallowing, and memory loss. Repeat MRI brain revealed new infiltrative FLAIR signal throughout the right temporal lobe extending from the posterior fossa, contiguous with the previously seen cerebellar findings and consistent with infiltrative glioma. Due to fragmented records and care in multiple systems, her updated MRI initially created a diagnostic challenge with a radiographic interpretation of likely encephalitis. This is a unique case documenting a middle-aged female with Li-Fraumeni syndrome, followed for multiple cancers, presenting with new neurologic symptoms and progressive infiltrative FLAIR changes spanning from the cerebellum into the right temporal lobe. These findings highlight the natural history of a TP53 deficient tumor that ostensibly responded to a cisplatin-based regimen given for a different indication, thereby delaying time to symptom onset and need for biopsy. Surveillance of low grade lesions in patients with underlying tumor predisposition syndromes must be interpreted in context of systemic disease burden and concurrent treatments for other neoplasms.