[A case of sinus pericranii manifesting as a parietal midline mass].

A case of sinus pericranii was reported. A 5-year-old boy was admitted to our hospital, complaining of scalp mass located at the midparietal region. He was noticed to have had it since 3 years before. The mass decreased in size under mild compression, and during standing position, but increased in size due to lying down. Magnetic resonance imaging (MRI) demonstrated a mass with mixed signal intensity on the T1 weighted image and high signal intensity on the T2 weighted image. Gd-DTPA study showed irregular enhancement. Cerebral angiogram showed no communication between the mass and the superior sagittal sinus. Neither did direct injection of contrast medium into the mass revealed any communication. 3D-CT demonstrated three tiny bone defects beneath the mass. Open surgery revealed that the mass existed between the galea aponeurotica and the periosteum, which had a small communication with the emissary vein. Pathological examination showed a multiple lobular cyst with endothelial wall lining. This case report highlighted the fact that sinus pericranii with minimal communication with the dural sinus can be treated by removal of the mass and closure of the cranial bone abnormalities with bone wax without craniotomy.