Spontaneous radiographic disappearance of cerebral aneurysms is often observed under special conditions such as giant aneurysms. However, spontaneous disappearance of an unruptured and nongiant intracranial saccular aneurysms is rare. We describe two cases of this rare vascular phenomenon. The first patient is a 64-year-old female diagnosed with a small unruptured aneurysm arising from the distal anterior cerebral artery. Spontaneous disappearance of the aneurysm on magnetic resonance angiography (MRA) was observed 5 years after the initial diagnosis. Continuous imaging surveillance also revealed spontaneous reappearance of the aneurysm 2 years later. The second patient is a 57-year-old female harboring a small unruptured saccular aneurysm arising from the M1–M2 bifurcation of the middle cerebral artery. The aneurysm showed spontaneous disappearance on MRA 13 years after the initial diagnosis. These cases provide a new insight into this natural dynamic process even in cases of a small unruptured intracranial saccular aneurysm.

No abstract

Background: Brain abscesses are relatively rare life-threatening infectious lesions often concomitant with a direct spillover of inflammation in the head or neck, hematogenous infections, and immunocompromised conditions. They rarely occur in adults without such predisposing factors. Prevotella is a well-known dental pathogen that very rarely causes brain abscesses. Case Description: We report such an abscess in a 51-year-old man who was innately healthy and had no oral lesions. A comprehensive computed tomography examination of the chest, abdomen, and pelvis, was inconclusive but a transesophageal echocardiogram bubble study revealed a mild patent foramen ovale (PFO) that matched Grade 1 criteria. We deduced that the right-left shunt due to the PFO could have contributed to the brain infection and treated the patient successfully via surgical abscess aspiration and antibiotics. Conclusion: In case of a brain abscess occurring in healthy adults, it is essential to investigate the source of infection and the existence of an arterio-venous shunt, such as PFO.