[A growing skull fracture: a case report].

A case of growing skull fracture was reported with some considerations on the literature. At the age of 1 year, the patient fell down stairs and struck the right occipital region, but did not receive any treatment at that time. At the age of 19 years, he suffered from several epileptic attacks and was admitted to our ward. Plain craniograms showed a right occipital bone defect measuring 7 x 3 cm in size. CT scan demonstrated a cystic lesion just beneath a membranous substance existing at the bone defect. MRI revealed cystic encephalomalacia underlying the cyst very clearly. At the operation the bone defect was found to be replaced by the granulation tissue which was examined microscopically. Under the granulation tissue, a cyst filled with yellowish fluid and surrounding gliotic brain was found. The dural tear was noticed to be much wider than the bone defect. A dural plasty with LYODURA and a cranioplasty with methacrylic resin were performed. Microscopic examination revealed the granulation tissue to be a fibroglial cicatrix. According to these findings, we concluded that the contused and swollen brain tissue which had herniated through the dural tear had enlarged the skull fracture and formed a fibroglial cicatrix with subcutaneous tissue. It is emphasized that MRI combined with CT scan is an indispensable procedure for diagnosis of growing skull fracture, and microscopic examination contributes to an understanding of its pathogenesis.