Infectious aneurysms account for about 5% of all cerebral aneurysms. Bacterial aneurysms are the most common, while mycotic ones are very rare and are usually associated with severe immunosuppression and prolonged antibacterial therapy. Most mycotic aneurysms have contact pathogenesis and develop in patients with fungal lesions of the paranasal sinuses and bones of the skull base. From the pathomorphology point of view, they are pseudoaneurysms and are unpredictable in terms of rapid growth and rupture; therefore, such patients require urgent intervention. The article presents a clinical case of a 50-year-old patient with a history of endonasal transsphenoidal removal of a pituitary adenoma 14 years ago. A few years later, the patient developed cerebrospinal fluid leakage with a series of meningitis episodes, including fungal origin, with the formation of mycotic granuloma in the lumbosacral spine. Subsequently, the patient developed left-sided ophthalmoparesis, and neuroimaging showed a mycotic pseudoaneurysm of the internal carotid artery. The aneurysm is isolated from the bloodstream by a flow-diverting stent.