Multiple Extracranial Metastases from Primary Gliosarcoma in aPatient with Two Previous Different Primary Cancers

Gliosarcoma (GS) constitutes a minor fraction of primary glioblastoma (GBM), which is the most frequent malignant braintumor in adults. Despite the fact that malignant gliomas are highly invasive, extracranial metastases are very rarely seen, andthe mechanisms behind extracranial dissemination are still unclarified. We report a case of a 55-year-old male with a priorhistory of two distinct primary cancer types who, as a third independent type, developed GS with penetrating tumor growthto the skull and subcutaneous soft tissue via explosive spreading through a titanium net as well as extracranial metastases tothe lumbar spine, paravertebral musculature, and most likely the right lung. The case illuminates the clinical challenge ofdiagnosing extracranial metastases from primary GBM and GS as these are still unexpected, especially in cases with possiblecompeting diagnoses.