Neurofibromatosis and Pituitary Tumours

Question 1

What is the inheritance patterns of neurofibromatosis type 1?

Answer 1

Type 1 (Von Recklinghausen’s syndrome) 
Autosomal dominant

Question 2

What are the clinical features of neurofibromatosis type 1?

Answer 2

Type 1 (Von Recklinghausen’s syndrome) 
Autosomal dominant 

Clinical Features
• Café au lait spots – seen on skin in 1st year of life, increasing in size and number with age, do no predispose to skin cancer.
• Freckling – typically in maxillary folds (axilla, groin, neck base and sub mammary area)
• Dermal neurofibromas – small nodules gelatinous in texture appearing at puberty and can become papillomatous.
• Nodular neurofibromas – arise from nerve trunks, form and demarcated and can cause paraesthesia
• Lisch nodules – tiny harmless, brown translucent mounds (hamartomas) on the iris
• Scoliosis
• Pheochromocytomas

Question 3

What are the complications of neurofibromatosis type 1?

Answer 3

Mild learning difficulties
Local effects of neurofibromas – nerve root compression, GI bleeds, obstruction, cystic lesions on bones, scoliosis, pseudoarthrosis.
Raised BP from renal artery stenosis or phaeochromocytoma
5% malignancy such as optic gliomas, sarcomatous change in a neurofibroma

Question 4

What are the diagnostic criteria for neurofibromatosis type 1?

Answer 4

2 of the following are found

1. > /= 6 café au lait spots
2. > /= 2 neurofibromas
3. Freckling in the axillary or inguinal regions
4. Optic glioma
5. > /= 2 Lisch nodules
6. Distinctive osseous lesion typical of NF1
7. First degree relative with NF1

Question 5

How is neurofibromatosis type 1 managed?

Answer 5

MDT with geneticist, neurologist, surgeon and physiotherapist and arranged by a GP
Monitor BP closely
Excise unsightly or irritant dermal neurofibromas

Question 6

How does neurofibromatosis type 2 differ from type 1 in terms of inheritance?

Answer 6

Autosomal dominant though 50% are de novo. Rarer than NF1

Question 7

What are the clinical features of neurofibromatosis type 2?

Answer 7

Café au lait spots but fewer than NF1
Bilateral vestibular (acoustic) schwannomas, presenting with sensory hearing loss age 20
Tinnitus and vertigo may also be present
Cataract formation at young age

Question 8

What are the complications of neurofibromatosis type 2?

Answer 8

Tender schwannomas or cranial and peripheral nerves

Glial tumours less common

Question 9

What are the diagnostic criteria for neurofibromatosis type 2?

Answer 9

Diagnostic criteria 
Either of the following found 
1.	Bilateral vestibular schwannomas
2.	First degree relative with NF2 and either unilateral vestibular schwannoma or:
•	Neurofibroma
•	Meningioma 
•	Glioma 
•	Schwannoma 
•	Juvenile cataract NF2 type

Question 10

How is neurofibromatosis type 2 managed?

Answer 10

Hearing tests yearly from puberty in affected families

MRI brain if abnormality detected

Question 11

What is the histological type of pituitary tumours?

Answer 11

These are almost always adenomas and account for a 10th of intracranial tumours. A microadenoma is <1cm across whilst a macroadenoma is >1cm across. Tumours are either secretory/functioning or non-secretory/non-functioning and.

Prolactinomas are the most common followed by non-secretory, then GH secreting and then ACTH secreting.

Question 12

What clinical features occur with pituitary tumours?

Answer 12

Headache (due to stretching of the dura within/around the pituitary fossa), visual field defects (bilateral temporal hemianopia), cranial nerve palsies (pressure of invasion of the cavernous sinus), Diabetes insipidus, disturbance of hypothalamic centres of Temperature, sleep and appetite.

Erosion through floor of skull leading to CSF rhinorrhoea.

Hormone effects – either over secretion or compression of the normal functioning of the pituitary e.g. Cushing’s, acromegaly, galactorrhoea, hypopituitarism etc.

Question 13

What investigations should be done for a patient with suspected pituitary tumour?

Answer 13

Prolactin, ACTH, IGF-1, TFT’s, LH/FSH, testosterone, glucose tolerance test and water deprivation test
Formal visual field testing
MRI scan with contrast

Question 14

How are pituitary tumours managed?

Answer 14

Hormone replacement if needed (give steroids before levothyroxine as it can induce an adrenal crisis).
Surgery – trans sphenoidal
If prolactinoma then medical management is 1st line with a dopamine agonist - bromocriptine
Monitor endocrine needs closely before, during and after surgery
Stereotactic radiotherapy

Question 15

What are the post op consequences of pituitary tumour surgery?

Answer 15

Need lifelong follow up due to possibility of recurrence

Fertility discussions

Question 16

What is pituitary apoplexy?

Answer 16

Pituitary apoplexy – acute hypopituitarism presenting with headache, meningism reduced GCS and ophthalmoplegia/visual field defect. Treat with steroids urgently – hydrocortisone and fluid stabilisation.