Spontaneous regression together with increased calcification of incidental meningioma

BACKGROUND Regression of meningioma has been reported after hemorrhage or hormonal withdrawal. However, meningioma regression is rarely observed spontaneously. CASE DESCRIPTION A right falx meningioma was incidentally diagnosed and was followed at every one-year by magnetic resonance imaging (MRI) for over 7 years. The tumor, with a maximum diameter of 4 cm, showed a slightly high density and was enhanced on computed tomography (CT), and a high intensity with a low-intensity core on T2 MRI, with significant edema. The meningioma gradually shrank together with a decrease of edema and increase of calcification. The initial volume, 25.5 cm(3), regressed linearly to less than half, 9.9 cm(3). CONCLUSION Here, we report a case of an incidentally diagnosed meningioma that regressed spontaneously. The pattern of the regression was similar to that following gamma knife radiosurgery.