Syndromes involving tumours Flashcards
Which neurocutaneous syndrome is not inherited via an autosomal dominant patter?
Sturge-Weber and ataxia telangiectasia
What is the incidence of NF1?
1 in 3000
What is the incidence of NF2?
1 in 40 000
Gene locus for NF2
Ch22 (22q12.2)
Gene locus for Von Recklinghausen’s disease?
Ch17 (17q11.2)
Which neurocutaenous syndrome is associated with skeletal anomalies?
NF1
What is the gene product of the NF2 gene?
Schwannomin
What is the gene product of the NF1 gene?
neurofibromin
What proportion of NF2 cases are sporadic?
>50%
What are the histological differences between schwannoma and neurofibroma?
Schwannomas arise from schwann cells, which produce myelin. Neurofibromas consist of neurites (axons or dendrites of immature or developing neurons), Schwann’s cells, and fibroblasts within a collagenous or myxoid matrix. Schwannomas displace axons (centrifugal), neurofibromas are unencapsulated and engulf the nerve of origin (centripetal). Both contain Antoni A and B fibres, neurofibromas tend to have more Antoni B. In NF-1 2% develop into malignant peripheral nerve sheath tumours.
What is the diagnostic criteria for NF-1?
(Mnemonic NFBLOCA) - NIH 1988 criteria Two or more of the following: ≥ 6 café au lait spots, each ≥ 5 mm in greatest diameter in prepubertal individuals, or ≥ 15 mm in greatest diameter in postpubertal patients ≥ 2 neurofibromas of any type, or one plexiform neurofibroma (neurofibromas are usually not evident until age 10–15 yrs). May be painful Freckling (hyperpigmentation) in the axillary or intertriginous (inguinal) areas Optic glioma ≥ 2 Lisch nodules: pigmented iris hamartomas that appear as translucent yellow/brown elevations that tend to become more numerous with age Distinctive osseous abnormality, such as sphenoid dysplasia or thinning of long bone cortex with or without pseudarthrosis (e.g. of tibia or radius) A first degree relative with NF1 by above criteria
Cause of hydrocephalus in NF-1?
Aqueduct stenosis
What does neurofibromin do?
Negative regulator of the Ras oncogene. Loss of neurofibromin function occurs in NF1 and results in elevation of growth-promoting signals.
What are the diagnostic criteria for NF-2?
(Mnemonic VFMSGPC) bilateral VS on imaging (MRI or CT) OR a first degree relative (parent, sibling, or offspring) with NF2 AND 1. unilateral VS OR 2. any TWO of the following: meningioma, schwannoma (including spinal root), glioma (includes astrocytoma, ependymoma), posterior subcapsular lens opacity, or cortical wedge cataract OR unilateral VS AND any TWO of the following: meningioma, schwannoma (including spinal root), glioma (includes astrocytoma, ependymoma), posterior subcapsular lens opacity, or cortical wedge cataract OR multiple meningiomas AND ONE of the following 1. unilateral VS OR 2. OR any TWO of the following: meningioma, schwannoma (including spinal root), glioma (includes astrocytoma, ependymoma), posterior subcapsular lens opacity, or cortical wedge cataract
What is the classical triad of tuberous sclerosis complex?
(Epiloia) Epilepsy Low inteillgence Adenoma sebaceum Full triad seen in <1/3 of cases
What is the inheritance pattern of Tuberous Sclerosis
Most cases are actually sporadic, otherwise autosomal dominant inheritance 2 genes identified TSC1 (Ch9) = Hamartin and TSC2 (Ch16) = Tuberin
What are the intracranial findings in Tuberous Sclerosis aka Bourneville’s disease?
Subependymal tubers (hamartomas) - almost always calcified SEGA (WHO grade 1, almost always at the foramen of Munro) - occur in 10% of TSC patients Cortical dysplasias Pachygyria / microgyria
How would you treat a SEGA in a patient with Tuberous sclerosis?
Resection if symptomatic Patients ≥ 3 years of age with increasing size of SEGA lesions have had sustained reduction of SEGA volume on everolimus (mTOR pathway inhibitor).
What is the diagnostic criteria for Sturge Weber syndrome?
Clinical criteria: 2 out of the following 3; Facial port-wine birth mark increased intra-ocular pressure leptomeningeal angiomatosis
How is sturge weber inherited?
Most cases are sporadic, somatic mutation in GNAQ gene on Ch9
What conditions are associated with neurocutaneous melanosis?
NF1
Sturge Weber
P-fossa cystic malformation (Dandy walker in 10%)
Intra spinal lipoma
Syringomyelia
Which brain tumour is most commonly associated with familial adenomatous polyposis? (BTP2)
Medulloblastoma
What are skin and CNS derived from embryologically?
Ectoderm
Which condition is associated with cutaneous schwannomas?
NF2 in 70%
Which condition is associated with Lisch nodules?
NF1 (not NF2!)
Which other conditions are associated with NF-1?
Mnemonic: SNAP SUM EKG Scwannomas Neurofibromas Aqueductal stenosis Phaeochromocytomas Syrinx UBOs Malignant tumours Exopthalmos Cognitive decline Kyphoscoliosos Gliomas
What are the clinical diagnostic criteria for tuberous sclerosis?
Need 2 major criteria or 1 major and 2 minor:
Major:
>2 Ash leaf macules (hypomelanotic) seen with a UV Woods lamp!
>2 angiofibromas
>1 ungal fibroma
Shagreen patch
Multiple retinal hamartomas
Cortical dysplasia
Subependymal nodules
SEGA
Cardiac rhabdomyoma
Lymphangioleiomyomatosis >1 angiomyolipomas
Minor: Confetti skin lesions Dental enamel pits Intraoral fibromas Renal cysts Non-retinal hamartomas
Mnemonic for Tuberous sclerosis features?
Mnemonic = USA ADORA CLASS C: Ungal fibromas Shahgreen patches Adenoma sebaceous / Angiofibromas Ash leaf macules Dental pits Oral fibromas Renal cysts Angiomylolipomas Cardiac rabdomyomas Lymphangioleiomyomatosis Achromic retinal patch Subependymoma SEGA Confetti skin lesions / calcified hamartomas
What is adenoma sebaceum?
Hamartomas of the skin
Where do calcifications occur intracerebrally in TSC?
Subependymal
What is the diagnosis of a contrast enhancing periventricular tumour in TSC?
SEGA enhance intensely
How do you resect SEGAs?
Interhemispheric Transcallosal
What are the diagnostic features of Sturge-Weber?
2 of:
Leptomeningeal angiomatosis
Ipsilateral port wine stain
Increased ocular pressures
(Localised cerebral atrophy and calcifications)
What are the classical features of Sturge-weber on skull xray?
Tram-track sign
What is the other name for Sturge Weber Syndrome?
Encephalotrigeminal angiomatosis
Where is the predilication for cortical calcification in Sturge-weber?
Occipital lobes
What features are associated with Sturge-Weber?
Mnemonic: EPIC GRAVE
Exopthalmos
Port wine stain
Iris Coloboma
Cortical atrophy / calcification
Glaucoma
Retinal angiomas
Atrophy of lobe
Oculomeningeal capillary haemangioma
Cerebral Venous malformation
Endocrinopathy (growth hormone deficiency)
What is the mutation in Tuberous Sclerosis?
TSC1 gene on Ch9q21 (Hamartin)
TSC2 gene on Ch16p13.3 (Tuberin)
How do you treat refractory seizures in tuberous sclerosis?
Lobectomy or hemispherectomy
What is the diagnosis?
Neurocutaneous melanosis
What is neurocutaneous melanosis?
A non-inherited phakomatosis that presents before 2 years of age with cutaneous and leptomeningeal benign or malignant melanomas. Due to a neuroectodermal defect originating from neural crest cells.
What % of patients with neurocutaneous melanosis develop hydrocephalus?
66%
What are the signal characteristics of melanin on MRI?
Bright T1 and Dark T2
What is Turcot syndrome?
Brain tumour polyposis syndrome 1 & 2 mutation of the APC - adenomatous polyposis syndrome gene)
Autosomal dominant
Type 1 is associated with gliomas
>90% have cafe-au-lait spots
Type 2 is associated with medulloblastomas
What is Li Fraumeni syndrome?
Autosomal dominant condition with P53 mutation causing medulloblastomas, embryonal tumorus and astrocytic tumours
What are these?
Lisch nodules (orange or brown iris hamartomas) associated with NF-1