A. Dechet 6/02
Cranial Nerves and Sellar Masses
Review of cranial nerves
Review of potentially confusing terms :
Visceral motor neurons from the Edinger-Westphal nucleus lead to the ciliary ganglion where the short ciliary
nerves end in the ciliary body and iris. These nerves control the constrictor pupillae and the ciliary muscles which
determine the size of the pupil and the curvature of the lens, respectively. Damage to unilateral axons or nucleus
will be demonstrated with loss of direct light reflex but preservation of consensual reflex. Accommodation reflex
is also affected by these pathways.
The medial longitudinal fasciculus coordinates the III and VI nerves on horizontal gaze. Lesions of the MLF
(termed internuclear ophthalmoplegia) are characterized by inability to gaze medially on the affected side upon
attempted lateral gaze. Will often see nystagmus on unaffected side. Accommodation reflex is still in tact.
Oculocephalic reflex (doll’s eye) is suppressed in conscious patients. In comatose patients the reflex is in tact
(positive doll’s eyes) when the patient’s eyes stay fixed on an object upon turning the head from side to side. It is
lost (negative doll’s eyes) when the eyes move with the head.
A. Benign tumors
1. Pituitary adenomas: Most common sellar mass after age 30. Arise from cells of anterior pituitary
(gonadotroph, thyrotroph, lactotroph, somatotroph, corticotroph). Often see hypersecretion of associated
hormone except gonadotrophs, but can see hyposecretion due to compression or neighboring cells.
2. Craniopharyngioma: Arise from remnants of Rathke’s pouch. Usually in childhood, but 50% present
after age 20. Usually present as growth retardation, visual loss, diabetes insipidus.
B. Malignant tumors
1. Primary malignancy
a. Germ cell tumors: “ectopic pinealomas” usually occur in early adulthood. Sx incl