Phakomatoses

Question 1

What are the features of Gorlin Goltz Syndrome (aka Basal Cell Nevus Syndrome)? It is characterized by the development of basal cell carcinoma (3rd decade or
older), odontogenic keratocystic tumors (2nd and 3rd decades), and other anomalies.

Answer 1

1. multiple basal cell carcinomas (97%), often at puberty and in adolescence
2. Craniofacial anomalies:
   - Odontogenic keratocysts, 74%, often multiple
   - Ectopic calcification of the falx cerebri, 65%
   - cleft palate/high arched palate, 5%
   - agenesis of corpus callosum (10%)
   - hypertelorism 10%
   - Frontal and parietal bossing, 26%
3. MSK anomalies:
   - shortened 4th metacarpal bones
   - bifid rib or other rib abnormality (fusion, partial agenesis, etc.)
4. neoplasms/hamartomas:
   - medulloblastoma: especially in males (M:F ~3:1)
   - calcified ovarian fibroma
   - lymphomesenteric cysts
   - fetal rhabdomyoma
   - cardiac fibroma(s)

Question 2

What are the intracranial manifestations of Neurofibromatosis 1?

Answer 2

1. Hamartomatous lesions – high T2 signal in globus pallidus, visual pathway, brainstem, cerebellum.
2. Optic pathway glioma.
3. Non-optic glioma – tectum, brainstem.
4. Plexiform neurofibroma.
5. Absent or dysplastic sphenoid wing, calvarial defects, dural ectasia.
6. Vascular abnormalities – aneurysm, ectasia, occlusion, moyamoya, AV fistula.

Question 3

What are the intracranial manifestations of Neurofibromatosis 2? “MISME”

Answer 3

1. Cranial nerve schwannomas – bilateral acoustic schwannomas are diagnostic.
2. Multiple meningiomas.
3. Intrinsic tumours (ependymomas).
4. Non-neoplastic choroid plexus lesions.

Question 4

What are the intracranial manifestations of Tuberous Sclerosis?

Answer 4

1. Cortical tubers.
2. Transmantle white matter dysplasia – high T2 signal on MRI.
3. Subependymal nodules – disorganized glial cells NOT heterotopic grey.
4. Giant cell astrocytoma – large glial nodules related to foramina of Monro.

Question 5

What are the intracranial manifestations of Von Hippel Lindau Disease?

Answer 5

1. Haemangioblastoma – usually cerebellar cystic tumour of variable size with avidly enhancing solid mural nodule; smaller tumours
   solid; may involve cord.
2. Retinal angioma, microphthalmia ± dystrophic calcification.

Question 6

What are the intracranial manifestations of Sturge-Weber Syndrome?

Answer 6

1. Gyriform subcortical calcification.
2. Gyriform enhancement postcontrast (pial angioma).
3. Focal atrophy related to angioma.
4. Hyperpneumatization of frontal sinuses.
5. Ipsilateral enlargement of choroid plexus.
6. Facial angioma.
7. Buphthalmos (globe enlargement), orbital angiomas.

Question 7

What are the intracranial manifestations of Hereditary Hemorrhagic Telangiectasia (Osler-Weber-Rendu Syndrome)?

Answer 7

1. Embolic infarcts – emboli through pulmonary AV shunts.
2. Cerebral abscess – septic emboli through pulmonary AV shunts.
3. Vascular malformations – telangiectasia, cavernomas, AVM and AVF.

Question 8

What are the clinical features of McCune Albright Syndrome?

Answer 8

Characterized by a triad of irregular café-au-lait
macules, polyostotic fibrous dysplasia, and precocious puberty. Pathologic fractures or narrowing of cranial foramina resulting in cranial nerve deficits have also been described