Cryptogenic Perirolandic Brain Abscess in an Otherwise Healthy Young Man

A previously healthy 19-year-old male presented with 1 day of transient right-sided weakness, numbness, and gait disequilibrium after recent self-limited sinonasal symptoms and minor nasal trauma with epistaxis. He was afebrile but with focal deficits, leukocytosis, and elevated C-reactive protein. Noncontrast head CT showed a left frontal lesion with vasogenic edema; MRI demonstrated a 2.4 × 1.4 cm rim-enhancing lesion in the left paramedian precentral gyrus with homogeneous diffusion restriction, low apparent diffusion coefficient, and surrounding edema. Stereotactic aspiration was performed within 24 h of presentation to obtain microbiological diagnosis and source control. A neuronavigated, transgyral frontal approach was used to avoid eloquent cortex. Empiric antimicrobials were initiated immediately after operative sampling. Postoperatively, the patient developed transient distal right lower extremity weakness that improved with supportive care and physical therapy. A thorough cardiac, dental, and thoracic evaluation did not reveal a source; the case was deemed cryptogenic. Operative cultures grew Streptococcus intermedius and Aggregatibacter aphrophilus. Targeted intravenous therapy was administered with near-complete radiographic resolution and full neurologic recovery at 4-month follow-up. This case emphasizes three practical principles for trainees: maintain suspicion for intracranial infection in afebrile young patients with new focal deficits and recent sinonasal symptoms; prioritize microbiological diagnosis and source control, while not delaying empiric therapy; and plan stereotactic trajectories that respect eloquent cortex and anticipate transient postoperative deficits. Early imaging, meticulous source evaluation and control, and directed therapy remain central to outcome.