An intrasylvian "fibroma" in a child with cystic fibrosis: Case report

OBJECTIVE AND IMPORTANCE: Intracranial fibrous tumors are uncommon during c hildhood. An unusual case of benign intrasylvian "fibroma" that has remaine d clinically and radiographically stable more than 3 years after a subtotal resection is described. CLINICAL PRESENTATION: A 9-year-old girl with cystic fibrosis presented wit h new-onset focal seizures referable to a large calcified left sylvian fiss ure mass. INTERVENTION: An open biopsy with subtotal resection of the lesion revealed a benign process characterized by exuberant fibrocollagenous tissue interm eshed with chronic inflammatory cells and foreign body giant cells, encompa ssing islands of gliotic brain tissue. Immunohistochemical analysis showed staining for epithelial membrane antigen and reticulin within some of the s pindle cells, although the majority were nonreactive. The majority of tumor cells exhibited staining for laminin; CD34 staining was absent. Ultrastruc tural studies were also suggestive of a fibroblastic rather than a meningot helial origin of the lesion, with elongated cells separated by abundant ext racellular collagen. Although dense adherence of the mass to the pial surfa ce and the middle cerebral artery vessels precluded a complete resection, t he patient remains seizure-free without anticonvulsant therapy more than 3 years postoperatively with no evidence of growth of the lesion. CONCLUSION: The lesion in this patient bears morphological similarity to a rare group of tumors referred to as "intracerebral fibromas," although a va riety of other rare mesenchymal neoplasms were also considered within the d ifferential diagnosis. However, the absence of any definite neoplastic feat ures, the finding of chronic inflammatory changes, and the lack of growth o f the residual tumor during an extended follow-up interval indicate that th e mass may represent either an extremely indolent neoplasm or a nonneoplast ic process. The differential diagnosis of intracranial fibrous tumors is co ntrasted with that of the reported case.