Related Experiment Video
Updated: Jan 25, 2026

Microscopic Cyst Resection for the Treatment of Patients Diagnosed with Epididymal Cyst
Published on: March 31, 2023
Epidermoid Cyst with Torcular Herophili Obstruction and Unusual Venous Drainage
Hiroshi Yokota1, Hiroshi Noguchi1, Kazuhiro Yokoyama1
1Department of Neurosurgery, Higashiosaka City General Hospital, Higashiosaka, Osaka, Japan.
Background:
An epidermoid cyst arising from diploic space in the skull can cause an intracranial mass effect with compression of the underlying venous sinuses.
Case Description:
A 66-year-old woman came to us with a persistent headache and unsteadiness. Computed tomography demonstrated an occipital bone cystic lesion with an intracranial mass effect overlying the torcular herophili, with high-intensity findings in diffusion-weighted magnetic resonance imaging. Cerebral angiogram demonstrated obstruction of the torcular herophili with development of diploic venous drainage. The patient underwent removal of the lesion and a cranioplasty procedure. The diagnosis was torcular epidermoid cyst. The postoperative course was uneventful, and the symptoms were resolved.
Conclusions:
Development of diploic venous drainage contributed to avoidance of critical intracranial hypertension during slow growth of a torcular epidermoid cyst.
Related Concept Videos
Unusual Results
According to the range rule of thumb, any value above or below two standard deviations, 2σ from the mean, μ is considered unusual.
Maximum unusual value =...
z Scores and Unusual Values
This score indicates how far a value is from the mean in terms of standard deviation. For example, if a data value has a z score of +1, the researcher can infer that the particular data value is one standard deviation above the mean. If another data...
Cavity Drainage and Flashings in Masonry walls
Weep holes, strategically placed at the base of the cavity, are critical for draining accumulated water. These openings are created by leaving head...
Venous Return
What is Venous Return?
Venous return refers to the rate at which blood flows back to the heart from the body's peripheral veins. It's an integral part of the circulatory system...
Venous Thrombosis I: Introduction
Chronic Obstructive Pulmonary Disease
Smoking is a primary risk factor for COPD, with over 80% of patients having a history of it. Patients typically experience progressive dyspnea or labored breathing, frequent coughing, and recurrent pulmonary infections. Many eventually succumb to respiratory failure, characterized by...

