Trochlear nerve meningioma in von Recklinghausen's disease.

A trochlear nerve meningioma in a patient with von Recklinghausen's disease is reported. The tumour appeared to have originated from the trochlear nerve itself, having no connection either with the neurinomas present in the adjacent regions, or with the tentorium. Histological examinations revealed that the tumour was a meningotheliomatous meningioma and the trochlear nerve fibres were placed in the periphery of the tumours. It was noteworthy that diplopia was not detected either before or after the resection of the trochlear nerve with the tumour.