Cranial Fasciitis of Childhood with Underlying Solid Aneurysmal Bone Cyst of Temporal Bone

Cranial fasciitis is a rare variant of pseudosarcomatous fibroblastic/myofibroblastic proliferation, seen almost exclusively in children. Most cases are idiopathic, though in some a history of trauma has been elucidated. Cases of suspected cranial fasciitis must be worked up radiologically to rule out intracranial extension. We present a case of cranial fasciitis in a ten-year old girl that showed involvement of temporal bone radiologically and subsequently turned out to be a solid aneurysmal bone cyst of the temporal bone on biopsy. It is likely that extralesional stromal hemorrhages from the cyst incited a reactive fibroblastic response in the form of cranial fasciitis in this case.