Abscess within a Glioblastoma: Mimicking a Matryoshka Doll

Background Abscess coexisting within a brain tumor is rare. Case reports in the literature primarily consist of sellar pathology and parenchymal lesions, including meningioma, glioma, and metastases. We report a case of glioblastoma with an intratumoral abscess in a middle-aged patient with no prior invasive procedure or systemic focus of infection. Case Description A 45-year-old woman presented with new-onset generalized seizures and rapidly progressive left hemiparesis. Imaging showed a right frontal necrotic lesion with a peripherally enhancing wall and solid component posteriorly. There was no diffusion restriction within the lesion. She was afebrile, and there was no systemic focus of infection. With provisional diagnosis of malignant glioma, she underwent surgical resection of the lesion. A differential diagnosis of abscess was considered preoperatively because of the rapid increase in size of the lesion. At surgery, there was a pus-filled cavity with a few areas of grayish, soft, flimsy wall and thrombosed veins. This raised a strong suspicion of a coexisting abscess within a malignant glioma, which was confirmed by histopathologic and microbiologic examination. Conclusions It is important for neurosurgeons to be aware of this rare entity. The treatment protocol remains controversial and is primarily guided by expert opinion. It is important to aggressively treat the patient with antibiotics followed by adjuvant therapy for malignancy. The timing and administration of adjuvant therapy are unclear. We suggest a delay of chemotherapy until at least 4 weeks of therapy with sensitive antibiotics.