Hamartoma, a rare cause of a prepontine mass

Abstract

A twenty-six year-old woman presented with one year history of involuntary left shoulder movements. She had a long-standing psychiatric history treated with haloperidol and benztropine, and had been diagnosed at age 9 with idiopathic precocious puberty because of tall stature for her age. She denied other symptoms or complaints. Her neurologic examination was significant only for uncontrolled spasms of her left trapezius. Routine laboratory and endocrine studies were unremarkable. MRI of the brain revealed a 20 • 30 mm mass adjacent to the clivus which displaced the brainstem posteriorly (Fig. 1 a, b). A four-vessel cerebral angiogram demonstrated this mass to be avascular.Biopsy was planned because of this tumor's unusual features and uncertain pathology. A right subtemporal craniotomy and open biopsy was performed with intra-operative auditory and facial nerve monitoring. The tumor was soft, avascular, and easily separable from the adjacent brainstem. Histopathologic examination of the biopsy specimen by Drs. F. Romanul and B. Wolf