TABLE 1:

Neuroradiologic findings

Patient No./Age (y)/Sex	Location	Size (cm)	Symptoms	Bony Anomalies	NECT (Compared to Brain)	T1WI (Compared to CSF)	T2WI (Compared to Brain)	FLAIR (Compared to CSF)	T1 C+ (Enhancement)	DWI (Restriction)
1/46/F	Right lower CPA	1.2 × 0.8 × 0.6	Decreased gag reflex on right, decreased sensation in right VI and V3 nerves	—	Isodense	Hyperintense	Hyperintense	Hyperintense	None	None
2/26/F	Midline, right lower CPA	2.6 × 1.6	Right-sided paresthesias, chronic migraine headaches	—	—	Hyperintense	Hypointense	Hyperintense	None	—
3/39/F^*	Midline, pontomedullary junction	0.6 × 1.4 × 1.1	Chronic headaches	—	—	Hyperintense	Hyperintense	Hyperintense	None	Mild
4/72/F	Left frontal lobe	8.8 × 4.6 × 6.6	Behavior changes leading to psychosis	—	Hypodense	Hyperintense	Hyperintense	Hyperintense	None	—
5/60/F	Midline, pontomedullary junction	1.5 × 0.8	Chronic headaches	—	—	Hyperintense	Hyperintense	—	—	—
6/unknown^*	Lateral pontomedullary junction	1.5 × 1	—	—	—	Hyperintense	Hyperintense	Hyperintense	Posterior rim (at brain)	—
7/41/F	Midline, lower CPA	2.5 × 1.5	Chronic headache, tingling in distal extremities	—	—	Hyperintense	Hyperintense	—	Posterior rim (at brain)	—
8/57/F	Midline, 4th ventricle	3.4 × 3 × 2.5	Occasional vertigo, chronic occipital headache	—	—	Hyperintense	Hyperintense	—	None	—
9/12/F	Midline, lower CPA	1.4 × 1.8 × 0.8	History of recurrent meningitis	Midline cleft, CVJ	—	Hyperintense	Hyperintense	Hyperintense	—	—
10/70/M	Midline to right lower CPA	3 × 4	Incontinence, inability to walk	—	—	Hyperintense	Hyperintense	—	—	—
11/26/F	Midline, anterior to medulla	1.5 × 2	2 episodes “viral syndrome” (headache, fever nausea, vomiting, nuchal rigidity, fever)	—	—	Hyperintense	Hyperintense	—	Posterior rim (at brain)	—
12/34/M	Left of midline, adjacent to calvarium, extending through left ethnoid	9 × 6 × 7	New onset seizures	—	Hypodense	Isointense	Hyperintense	—	None	—
13/21/F	Midline, anterior to brain stem extending into both CPA cisterns	3 × 2.5	“Migraines,” persistent occipital headaches	—	Hyperdense	Hyperintense	Hypointense	Hyperintense	—	—
14/44/F	Lower left CPA	3 × 3	Progressive clumsiness of hands with gait disturbance	—	—	Hyperintense	Hyperintense	—	None	—
15/14/F	Right CPA	2 × 2 × 2	Long history of right-sided sensorineural hearing loss	—	—	Hyperintense	Hyperintense	—	Posterior rim (at brain)	—
16/78/F	Extra-axial right frontal lobe, with fluid-fluid levels	7 × 5 × 3	Acute onset single seizure	—	Isodense	Iso-hyperintense	Hyperintense	—	None	—
17/48/M	Left intra/paraventricular, bilobed	8 × 5	2 weeks of tremor, numbness of right arm, and facial droop	—	Hyperdense, marginal Ca++	Hyperintense	Hyperintense	—	Thin marginal enhancement	—
18/78/M	Extra-axial, frontal lobe, multiple fluid-fluid levels	7 × 5 × 3	New onset seizure	—	Hypodense	Hyperintense	Hyperintense	—	None	—

Note:—CPA indicates cerebellopontine angle; NECT, nonenhanced CT; T1WI, T1-weighted image; T2W1, T2-weighted image; T1 C+, T1 with gadolinium; DWI, diffusion-weighted image; CVJ, craniovertebral junction.
* Presumed neurenteric cyst