Paediatrics: Neurocutaneous disorders

Neurocutaneous disorders

Tuberous sclerosis complex (TSC)

·  TSC is an autosomal dominant inherited disorder affecting brain, skin, heart, kidney, eye, and lung.

·  The disorder is caused by haematomata affecting the above organs, although other neoplasms also occur.

·  Two genes have been identified: TSC 1 and 2. About 1/3 of cases are inherited, the others de novo mutations.

Diagnosis of TSC

The diagnosis is made when a child has either 2 major, or 1 major and 2 minor criteria.

Management

Treatment is symptomatic depending on the organ-specific effects of the haematoma and neoplasms. All cases require expert assessment:

·Recurrence risk in family members.

·Symptomatic epilepsies, particularly if West syndrome occurs.

·Cardiac rhabdomyomata need to be referred to cardiology support, but if echo/ECG is normal, then they can be discharged as these do not develop postnatally.

·Renal complications are very rare * under 9yrs, but after this bi-annual renal ultrasound with regular enquiry for renal function/loin pain is needed. Polycystic kidney disease can occur if there is contiguous deletion of the neighbouring gene.

·Pulmonary lymphangiomatosis occurs very rarely in childhood, and only in girls. Regular screening is not indicated, unless a history given of respiratory symptoms.

·Ophthalmological haematomata need to be referred to ophthalmology. If fundi are normal, patients can be discharged as these lesions do not develop post-natally.

Neurofibromatosis

There are 2 distinct AD disorders, char-acterized by multiple benign tumours of the peripheral nerve sheath.

NF1: chromosome 17

The diagnosis is based on having at least 2 of the following:

·>6 café au lait macules: >5mm diameter before puberty; >15mm diameter after puberty.

·Skin fold or axillary freckling.

·1 Neurofibroma or a plexiform neurofibroma.

·1 Lisch nodule in iris.

·Optic glioma.

·Skeletal dysplasia.

·Affected first-degree relative.

The management of this condition is symptomatic and depends on the local effects of the neurofibroma. However, all cases require expert assessment of:

·recurrence risk in family members (they need assessment annually);

·neoplasia and optic gliomata;

·renal artery stenosis;

·skeletal dysplasia;

cognitive performance.

NF2: chromosome 22

The diagnosis is based on having 1 major or 2 minor criteria.

·  Major criteria:

·  unilateral vestibular Schwannoma and first-degree relative with NF2;

·  bilateral vestibular Schwannomas.

·  Minor criteria:

·  meningioma;

·  Schwannoma;

·  ependymoma;

·  glioma;

·  cataract.

The management of NF2 is complex as the tumours themselves do not need to be removed when identified in many cases, although they may be symptomatic.

Sturge–Weber syndrome

·  Leptomeningeal angiomatosis: associated with a port wine naevus in the distribution of the first branch of the trigeminal nerve.

·  Children may be very well, but can have severe focal epilepsies, learning disability, hemiplegia, glaucoma, and transient stroke-like episodes, and severe headaches.

Diagnosis: on facial appearance and CT ± MRI scan.