Rapidly Growing Thalamic Abscess

A 54-year-old woman presented with a right-sided sensory and motor syndrome without headache. She was not immunocompromised or febrile. Two weeks earlier, she had undergone an uncomplicated tooth extraction. The laboratory results were normal. A cranial computed tomography scan revealed a hypodense lesion in the left thalamic region (Figure 1A). Magnetic resonance imaging (MRI) performed the next day showed a contrast-enhancing lesion in this region (Figure 1B) and signs of edema (Figure 1C). Whole-body 18F-fluoro-2-deoxyglucose (FDG)–positron emission tomography performed 3 days later demonstrated an FDG-negative round-shaped lesion without wall uptake (Figure 1D) compatible with an abscess. As the patient’s neurological findings deteriorated (psychomotor slowing, deteriorating hemisyndrome), an MRI 4 days later showed a markedly growing thalamic lesion. The calculated volume increased within 4 days from 1 to 11 cm3 (Figure 1B and andEE).1 Neurosurgery was consulted and stereotactic abscess drainage was performed, combined with initiation of an antibiotic regimen. A causative pathogen, Streptococcus intermedius (Milleri), was isolated. Within 6 weeks, the patient recovered appreciably