Abstract Number: Esoc2026a2445 Cerebellar Cavernomas Mimicking Brain Metastasis in a Patient With Previous Breastcancer: A Diagnostic and Therapeutic Challenge

Abstract Background and aims Cerebral cavernous malformations (CCMs) are low-flow vascular lesions that remain asymptomatic or present with seizures, focal deficits, or hemorrhage. A supratentorial, cerebellar localization is rare and poses a diagnostic challenge, particularly in oncological patients. We report a case of multiple cerebellar cavernomas with an acute onset and radiological features initially mimicking metastatic lesions Methods A 64-year-old female with a history of left breast cancer (Luminal B, HER2-positive, treated in 2011 with surgery, chemotherapy, and radiotherapy) and cutaneous melanoma was admitted for vertigo, diplopia, and postural instability. Initial Brain CT imaging revealed right cerebellar lesions with perilesional edema and mass effect on the fourth ventricle. Given the oncological background, a metastatic process was initially suspected. Further investigations included brain MRI, tumor marker screening, and specialist consultations. A neurogenetic test was also performed due to the multiplicity of lesions. Results MRI revealed a cluster of cavernous malformations in the right cerebellar hemisphere, signs of recent bleeding associated with edema, and compression of the fourth ventricle. Tumor markers were within normal limits, and a total-body CT excluded extracranial metastases. The patient underwent worsening neurological symptoms, prompting urgent transfer to a neurosurgical unit for resection. Postoperative MRI showed no residual lesions, and the patient became asymptomatic Conclusions This case underscores the diagnostic complexity of cerebellar cavernomas in oncological patients, as their imaging characteristics may resemble metastatic disease due to hemorrhage and mass effects. A multidisciplinary approach, including advanced neuroimaging and genetic evaluation, is crucial for proper diagnosis and individualized care. Conflict of interest Marianna Rima:nothing to disclose; Stefano Luca Sensi: nothing to disclose; Massimo Caulo: nothing to disclose; Gianluca Trevisi: nothing to disclose Figure 1 - belongs to Results