Histiocytic lesion mimicking intrinsic brainstem neoplasm - Case report

This 10-year-old girl presented with a 1-month history of progressive bulba r palsy and a solitary enhancing mass originating within the floor of the f ourth ventricle. Results of initial imaging studies and presentation were s uggestive of neoplasia. Subtotal resection was performed and pathological e xamination revealed the mass to be a histiocytic lesion, with no evidence o f a glioma. The patient had no other stigmata of histiocytosis and was trea ted with steroid medications, resulting in prolonged resolution of the lesi on. This case demonstrates that for discrete brainstem lesions the differen tial diagnosis includes entities other than glioma for which treatment is a vailable. Biopsy sampling should be considered when technically feasible.