BRAIN METASTASIS FROM MELANOMA OF UNKNOWN PRIMARY: A CHALLENGING DIAGNOSIS. CLINICAL CASE REPORT

Abstract

DOI: https://doi.org/10.46296/gt.v8i16.0326

Abstract

Introduction: Cutaneous melanoma has a high propensity to metastasize to the central nervous system (CNS). In a minority of patients, the metastasis is identified without the primary tumor being found despite exhaustive evaluation, an entity known as melanoma of unknown primary (MUP). When the initial presentation involves the brain, the differential diagnosis includes primary CNS tumors and hemorrhagic metastases from other origins (2,12). Case presentation: A 58-year-old man, with no prior history of cancer, presented with progressive headache and focal seizures with secondary generalization. Computed tomography revealed a hyperdense right parietal corticosubcortical lesion with vasogenic edema and a slight mass effect. Magnetic resonance imaging showed a single lesion with peripheral enhancement and signs of intralesional hemorrhage. Surgical resection was performed. Histopathological and immunohistochemical studies (SOX10, S100, HMB-45, Melan-A) confirmed brain metastases from melanoma, and molecular analysis documented a BRAF V600E mutation. Subsequent staging (dermatology, mucosal, ophthalmology, and PET-CT) did not identify a primary lesion, so it was classified as MUP (1,11,12,14). Discussion: Brain metastases from melanoma have a tendency to hemorrhage and can mimic primary lesions. Current management is based on multimodal strategies: surgery for symptomatic or mass-effect lesions, focal radiotherapy (SRS), and effective systemic therapies, particularly immune checkpoint inhibitors. Long-term trials and follow-up support the ipilimumab + nivolumab combination for its intracranial activity and sustained survival benefits in selected patients (3,4,7,8,9,16). Conclusions: In a patient with no known cancer, metastatic melanoma should be considered even without an identifiable primary tumor. Histological confirmation and multidisciplinary management allow for the implementation of contemporary therapies with potentially favorable impact on intracranial control (1,2,3,4).

Keywords: Melanoma; Brain metastasis; Neoplasms of unknown origin; Radiosurgery; Immunotherapy; Case report.