Symptoms range from nonexistent to profound; the condition is occasionally discovered by brain imaging performed for an unrelated problem and has no apparent ill effect on the patient. At the other extreme, heterotopia can result in severe seizure disorder, loss of motor skills, and mental retardation. Fatalities are practically unknown, other than the death of unborn male fetuses with a specific genetic defect.

Periventricular or subependymal
Periventricular means beside the ventricle, while subependymal (also spelled subepydymal) means beneath the ependyma; because the ependyma is the thin epithelial sheet lining the ventricles of the brain, these two terms are used to define heterotopia occurring directly next to a ventricle. This is by far the most common location for heterotopia. Patients with isolated subependymal heterotopia usually present with a seizure disorder in the second decade of life.

Subependymal heterotopia present in a wide array of variations. They can be a small single node or a large number of nodes, can exist on either or both sides of the brain at any point along the higher ventricle margins, can be small or large, single or multiple, and can form a small node or a large wavy or curved mass.

Symptomatic women with subependymal heterotopia typically present with partial epilepsy during the second decade of life; development and neurologic examinations up to that point are typically normal. Symptoms in men with subependymal heterotopia vary, depending on whether their disease is linked to their X-chromosome. Men with the X-linked form more commonly have associated anomalies, which can be neurological or more widespread, and they usually suffer from developmental problems. Otherwise (i.e., in non-X-linked cases) the symptomology is similar in both genders.

Focal Subcortical
Subcortical heterotopia form as distinct nodes in the white matter, “focal” indicating specific area. In general, patients present fixed neurologic deficits and develop partial epilepsy between the ages of 6 and 10. The more extensive the subcortical heterotopia, the greater the deficit; bilateral heterotopia are almost invariably associated with severe developmental delay or mental retardation. The cortex itself often suffers from an absence of gray matter and may be unusually thin or lack deep sulci. Subepedymal heterotopia are frequently accompanied by other structural abnormalities, including an overall decrease in cortical mass. Patients with focal subcortical heterotopia have a variable motor and intellectual disturbance depending on the size and site of the heterotopion.

Band form

Like focal subcortical heterotopia, “band” heterotopia form in the white matter beneath the cortex, but the gray matter is more diffuse and is symmetric between the hemispheres. On imaging, band heterotopia appears as bands of gray matter situated between the lateral ventricle and cerebral cortex and separated from both by a layer of normal appearing white matter. Band heterotopia may be complete, surrounded by simple white matter, or partial. The frontal lobes seem to be more frequently involved when it is partial. Patients with band heterotopia may present at any age with variable developmental delay and seizure disorder, which vary widely in severity.

Gray matter heterotopia Sag T2 Flair

Gray matter heterotopia Cor T2 Flair

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The cause of osteomata is uncertain, but commonly accepted theories propose embryologic, traumatic, or infectious causes. Osteomata are also found in Gardner’s syndrome.

Larger craniofacial osteomata may cause facial pain, headache, and infection due to obstructed nasofrontal ducts.

Often, craniofacial osteoma presents itself through ocular signs and symptoms (such as proptosis).
Variants
“Osteoma cutis, but there is currently no way of detecting if and when this is likely to occur.
“Fibro-osteoma”
“Chondro-osteoma”

Plain x-rays of the shoulder can be used to detect some joint pathology and variations in the bones, including acromioclavicular arthritis, variations in the acromion, and calcification. However, x-rays do not allow visualization of soft tissue, thus hold a low diagnostic value. Ultrasonography, arthrography and MRI can be used to detect rotator cuff muscle pathology.

MRI is the best imaging test prior to arthroscopic surgery. Due to lack of understanding of the pathoaetiology, and lack of diagnostic accuracy in the assessment process by many doctors, several opinions are recommended before intervention.

The venous angioma have usually form a little cluster (“star burst” or “caput Medusae” – looks like a “head of snakes”), and these veins generally drain into a larger “collector” vein. The collector vein is usually on the surface of the brain, but sometimes there may be deep drainage too.

The pattern of these veins is frequently simple, but may at times be more complex looking. Between the veins that make us the venous angioma is normal brain tissue. Sometimes one or more of these veins can appear extra dilated and may be more thin walled than other veins in the brain. Venous angiomas tend to occur near the frontal horns of the ventricles (fluid filled spaces of the brain) and also in the cerebellum (small part of the brain at the lower back part of the head).

Most subdural hygromas are small and clinically insignificant. Larger hygromas may cause secondary localized mass effects on the adjacent brain parenchyma, enough to cause a neurologic deficit or other symptoms. Acute subdural hygromas can be a potential neurosurgical emergency, requiring decompression. Acute hygromas are typically a result of head trauma—they are a relatively common posttraumatic lesion—but can also develop following neurosurgical procedures, and have also been associated with a variety of conditions, including dehydration in the elderly, lymphoma and connective tissue diseases.

It is not uncommon for chronic subdural hematomas (SDHs) on CT reports for scans of the head to be misinterpreted as subdural hygromas, and vice versa. Magnetic resonance imaging (MRI) should be done to differentiate a chronic SDH from a subdural hygroma, when clinically warranted. Elderly patients with marked cerebral atrophy, and secondary widened subarachnoid CSF spaces, can also cause confusion on CT. To distinguish chronic subdural hygromas from simple brain atrophy and CSF space expansion, a gadolinium-enhanced MRI can be performed. Visualization of cortical veins traversing the collection favors a widened subarachnoid space as seen in brain atrophy, whereas subdural hygromas will displace the cortex and cortical veins.

In the majority of cases, if there has not been any acute trauma or severe neurologic symptoms, a small subdural hygroma on the head CT scan will be an incidental finding. If there is an associated localized mass effect that may explain the clinical symptoms, or concern for a potential chronic SDH that could rebleed, then an MRI, with or without neurologic consultation, may be useful.

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Affected persons have difficulty in swallowing (dysphagia) resulting from involvement of the nucleus ambiguus, as well as slurred speech (dysarthria) and disordered vocal quality (dysphonia) . Damage to the spinal trigeminal nucleus causes absence of pain on the ipsilateral side of the face, as well as an absent corneal reflex.

The spinothalamic tract is damaged, resulting in loss of pain and temperature sensation to the opposite side of the body. The damage to the cerebellum or the inferior cerebellar peduncle can cause ataxia. Damage to the hypothalamospinal fibers disrupts sympathetic nervous system relay and gives symptoms analogous to Horner syndrome.

Nystagmus and vertigo, which may result in falling, caused from involvement of the region of Deiters’ nucleus and other vestibular nuclei. Onset is usually acute with severe vertigo.

Palatal myoclonus may be observed due to disruption of the central tegmental tract.