A clinical suspected case of cerebral syphilitic gumma showing spontaneous regression

A 46-years-old man who complained of headache for 4 months was transported our hospital due to vertigo and nausea. Gadolinium-enhanced T1WI showed ring-like enhancements in the right pedunculus cerebellaris medius and left frontal lobe on the brain surface. Additionally, FLAIR images showed high intensity area indicating perilesional edema. We diagnosed the patient as neurosyphilis with his serum and cerebrospinal fluid findings, and considered him as cerebral syphilitic gumma because of brain MRI findings. An HIV test was negative. Follow-up MRI before treatment demonstrated spontaneous regression of these lesions, and after intravenous treatment with penicillin G for 14 days complete regression. Since then, he has had no sign of recurrence. Although there are some characteristic brain MRI findings of cerebral syphilitic gumma, spontaneous regression of these lesions in this case was an unusual finding.