Robot-Assisted Stereotactic Aspiration of a Parietal Brain Abscess With Metagenomic Identification of Fusobacterium nucleatum

Robot-assisted stereotactic aspiration offers a minimally invasive approach to brain abscesses near the eloquent cortex. We report a rare case of a left parietal abscess caused by Fusobacterium nucleatum in an immunocompetent adult, managed successfully with this approach. The patient, a 52-year-old man, presented with right-sided limb numbness. MRI and contrast-enhanced CT revealed a cystic, ring-enhancing lesion with diffusion restriction in the left parietal lobe. Despite empiric broad-spectrum antibiotics, neurological deterioration occurred due to progressive mass effect. Robot-assisted stereotactic aspiration enabled single-stage, precise drainage of the abscess. Metagenomic next-generation sequencing identified F. nucleatum , prompting adjustment of antibiotics to ceftriaxone plus metronidazole, followed by metronidazole monotherapy. The patient improved clinically, and a 6-month MRI confirmed complete resolution, underscoring the precision of robotic stereotaxy for eloquent-region abscesses and highlighting the diagnostic value of metagenomic sequencing in detecting anaerobic pathogens.