Cerebral gumma showing spontaneous regression on magnetic resonance imaging study--case report.

A 75-year-old male presented with the complaint of headache. Magnetic resonance (MR) imaging demonstrated a low-signal intensity area on both T1- and T2-weighted images with ring-like enhancement and adhesion of the dura appearing as dural tail sign. Follow-up MR imaging demonstrated spontaneous regression, so the preoperative diagnosis was malignant lymphoma. Histological examination revealed typical granuloma. Treponema pallidum hemagglutination assay tests of serum and cerebrospinal fluid were positive for active syphilis. The enhanced mass totally disappeared after 4 months of erythromycin therapy. The final diagnosis was cerebral gumma. The incidence of syphilis is increasing, so cerebral gumma should be included in the differential diagnosis of hypovascular tumors that involve both the parenchyma and dura even in the presence of spontaneous regression.