Related Experiment Video
Updated: Dec 5, 2025

Surgical Treatment of an Endolymphatic Sac Tumor
Published on: May 26, 2023
[A Case of Trochlear Nerve Neurinoma Presenting with Pathological Laughter]
Nozomi Sasaki1, Akihide Matsuda, Kiyomitsu Kanou
1Department of Neurosurgery, Asahi University Hospital.
Abstract:
Trochlear nerve neurinomas are rare and solitary tumors without neurofibromatosis are extremely rare. We report a case of trochlear nerve neurinoma presenting with pathological laughter and diplopia. A 40-year-old male patient presented with diplopia and pathological laughter 2 months before admission. MRI showed a multicystic enhanced mass in the left tentorial incisura compressing the midbrain and the upper pons. The tumor was excised using the left trans-Sylvian approach with partial uncal resection. After excision of the tumor, the left trochlear nerve was identified on the surface of the lateral midbrain. The nerve was connected to the tumor. Pathological laughter completely resolved after the operation. This is the second reported case of trochlear nerve neurinoma presenting with pathological laughter. The lesion responsible for pathological laughter could be the midbrain, upper pons, diencephalon, or all of these.
Related Concept Videos
Cranial Nerves: Types Part II
Facial Nerve (Cranial Nerve VII)
Cranial nerve VII, or the facial nerve,...
Cranial Nerves: Types Part I
Olfactory Nerve (Cranial Nerve I)
The olfactory nerve, or cranial nerve I, is unique as it is purely sensory and dedicated to the sense of smell. This nerve originates in the olfactory epithelium of the...
Neural Regulation
Cranial Nerves: Overview and Anatomy
Prosopagnosia
Somatic Spinal Reflexes
One of the most well-known somatic spinal reflexes is the stretch reflex, which is activated by the sudden stretching of a muscle. This reflex involves the activation of specialized sensory receptors called muscle spindles, which are located in the muscle tissue and detect changes in the length and speed of muscle contractions. When a muscle is suddenly...

