Dialog Box

Children's Tumour Foundation


The information provided is not meant to replace the advice from your medical team, nor is it a complete list of terms, but will hopefully help you to understand more of the technical terms. More terms and definitions will be added to the page on an ongoing basis, so if there is a term you want clarity on, but can't find here, please drop us an email on support@ctf.org.au

Accoustic Neuroma

Is another term for a vestibular schwannoma, a tumour that can form on the nerve that takes sound and balance information to the brain (the 8th cranial nerve).


A test available during mid-pregnancy to look for genetic changes in an unborn baby. This is done by ...


Are a type of tumour found in the brain and or spinal cord, and depending on where the astrocytoma is found, the symptoms can be quite different. Some are not detected and are indolent. This means they do not cause any symptoms or pain. For tumours in the brain, dizziness, seizures and changes in behavior may be the warning signs. If the tumours are in the spinal cord, then pain and weakness are usually the first things noticed. An MRI will be performed to properly diagnose whether a tumour is present. (see also ependymoma).

Auditory Brainstem Implant (ABI)

A device that aids in providing a sense of sound when the hearing nerve is no longer working. It does this by bypassing the cochlea and hearing nerves

Autosomal dominant

Is the term used to describe the inheritance pattern of NF and other genetic conditions where

Café Au Lait Spots (Cals)

Are flat, light brown (coffee coloured – hence the name) spots that can appear on the skin throughout life. Café au lait spots are found on just about everyone with NF1. These are harmless but are used as a diagnostic criteria for NF1.

Chorionic Villus Sampling (CVS)

A test available at the end of the first trimester of pregnancy

CT Scans

CT stands for Computerised Tomography and is used to scan the body. CT scans use X-rays and digital computer technology to create detailed three-dimensional pictures. Multiple X-ray projections are taken in thin cross-sections along the person’s body and are then combined to form an image.

Ependymal Cells

Ependymal cells are


Ependymoma is a tumour arising from the cells that line the brain and spinal cord. These tumours generally occur in people with NF2 but it is quite rare (see also astrocytoma).


Freckling (aka Skinfold Freckling) is the term used to describe a cluster of small, brown freckles. These are usually found in the groin or under the armpit and like café au lait spots, they are harmless, but help doctors diagnose NF1.

Glial Cells

Glial cells support the nerves in our bodies.


Hamartomas are small benign


Hydrocephalus is the term used to describe a buildup of fluid in the brain which can result in a larger than normal head size. The brain and spinal cord are surrounded by a layer of fluid called Cerebro Spinal Fluid (CSF) which circulates around the brain and spinal column. If there is a blockage of the fluid flow, the pressure can increase and cause hydrocephalus and associated neurological problems. Extreme and untreated cases can result in the head becoming very large. It occurs in less than 2% of people with NF and can start from 6 years of age. Generally, the risk of Hydrocephalus is passed after the age of 35.  

Lisch Nodules

Lisch nodules or harmatomas are small, dome-shaped lumps that form on the surface of the eye. They are found in almost everyone who has a diagnosis of NF1. Lisch nodules are usually brown in colour and appear when a child is around 5 years of age. They are found on the iris (the coloured part of the eye) but do not interfere with vision in any way and are harmless. Lisch nodules are only diagnosed by an ophthalmologist using a special slit lamp but do not require any treatment. They are helpful in the diagnosis of NF1 and they do not occur in people with a diagnosis of NF2. 

Malignant Peripheral Nerve Sheath Tumour (MPNST)

Are aggressive cancers that generally originate in a plexiform neurofibroma. They occur in 5-10% of people with NF1 (often when a person is in their 20-30s) but are rare in the general population. If a plexiform neurofibroma grows rapidly, changes form or becomes painful or hard, it should be investigated as soon as possible. Usually a biopsy will be performed followed by surgery. These tumours can spread quickly so prompt treatment is essential.  


The term used to describe a larger than normal head circumference. This occurs in approximately 45% of children with NF1 but has no link to cognitive function or abilities.  

Magnetic Resonance Imaging (MRI)

A scan used to take high resolution pictures inside the body. It uses a magnetic field and radio waves to take images of soft tissue such as organs, tissues and muscles that don’t show up on x-rays. MRI scans are costly and are only recommended when there is a clinical reason and are not used for routinely examining people with NF. As many as 60% of children and adolescents can have UBOs found on MRI scans, although these usually disappear during adulthood. UBO’s are Unidentified Bright Objects which are areas of signal hyperintensity seen on the scan. No one really understands these bright spots yet, but researchers do not think they are linked to NF severity, learning difficulties or cancerous tumours.  


A type of tumour that develops on the membrane that surrounds the brain. 


Neurofibromas are benign tumours found on or within the body. All Neurofibromas grow from the tissue surrounding a nerve fiber. Neurofibromas generally appear in late childhood or early adolescence when hormones can affect the growth rate. They can be small, pea sized lumps or up to several centimeters in size. 

Cutaneous or Dermal Neurofibromas are found on or under the skin. They are slow growing, usually soft and malleable (moveable), and can look smooth or like a collection of bumps. 

Subcutaneous Neurofibromas are found deeper in the body and are firmer to the touch. Discrete neurofibromas are encapsulated, meaning they have definite edges or borders. Most people with NF1 have only several neurofibromas, but more rarely, some people can have hundreds or thousands of them, most commonly on the chest, arms and back. While they can be disfiguring if they appear on the face, neurofibromas are generally only removed it they cause concern or pain or are in an inconvenient location (e.g. under a bra strap). 

It is extraordinarily rare for a discrete neurofibroma to become cancerous. However, they may have a detrimental impact on body systems by pressing on bone, nerves or other tissue, but will not invade these other structures. On the other hand, plexiform neurofibromas can wrap themselves around blood vessels and nerves and can therefore be more difficult to treat. (see Plexiform neurofibroma)  


Neurons are the name given to nerve cells.


Ophthalmologist is a doctor who specialises in vision and the eye. These doctors are trained to perform eye examinations, diagnose eye conditions, prescribe medications or otherwise treat them and to perform surgery on the eye.

Optic Nerve Glioma

Optic Nerve Glioma (OPG) is a tumour that can develop behind the eye. They occur in about 15% of children with NF1 and usually appear between the ages of 4 and 6. Tumours can start in the cells surrounding the Optic Nerve (which connects the eyeball to the visual cortex in the brain) or in the Optic Chiasm (where the two optic nerves cross). Most Optic Nerve Gliomas are slow growing and do not require treatment. Only 5% of children with NF1 will experience visual disturbances as a result of an OPG. 

Position Emission Tomography (PET) Scan

An imaging test that helps to determine how well your body’s tissues and organs are functioning.


Are benign tumours that grow in the adrenal gland. The adrenal gland is located at the top of the kidney and controls hormones. If a tumour develops here, the person is in danger of having very high blood pressure and a fast heart rate. Most pheochromocytomas are benign but do require surgical remova

Plexiform Neurofibromas

Plexiform neurofibromas are large and diffuse benign tumours that generally occur deep within the body. They are estimated to occur in one third of people with NF1, although these can be asymptomatic in some people (they don’t know they have one as it does not cause any problems). 

Plexiform neurofibromas are usually congenital (meaning the person was almost certainly born with it). People with NF may have a darker or thicker patch of skin which is indicative of an underlying plexiform neurofibroma. Plexiform neurofibromas on the face are usually obvious in the first year of life. Others can grow throughout childhood, but new ones rarely form after puberty.  

Plexiform neurofibromas, unlike discrete neurofibromas, are large and can invade other structures like bones and organs. They often have their own blood supply which makes them difficult to excise surgically and are likely to regrow if they are removed. Less than 10% of Plexiform neurofibromas may become malignant (cancerous). If a plexiform neurofibroma become painful or hard it needs to be investigated promptly (see also MPST).  


The medical term for itch. Constant itchiness is reported in approximately 20% of people with NF. General skin care and avoidance of perfumed soaps is recommended. 


Occurs when a long bone is broken but does not heal properly. This results in a “false” (pseudo) joint forming. It occurs in only 2% of NF1 children, usually occurs within the leg (tibia or fibia), but can also involve the arm bones. Pseudoarthroses rarely repair on their own and require surgery to correct. Surgery will aim to repair the old fracture, stabilise the bones and reduce leg length discrepancies. Extreme cases can result in amputation of the limb to reduce pain and enhance quality of life for the patient.


A schwannoma is a benign tumour that arises from Schwann Cells. Schwann cells form myelin, which is the “insulation” around nerves. Schwannomas are characteristic of NF2 and Schwannomatosis.  Vestibular schwannomas often develop in late teens or early adulthood and occur on the 8th cranial nerve. This nerve is responsible for hearing and balance and as such, NF2 is often diagnosed after people experience dizziness, balance problems and hearing loss.  

Schwannomas can also occur on other cranial nerves. Schwannomas grow slowly on the outside of nerves but can press on nerves or push them onto other structures causing pain and neurological complications. Schwannomatosis refers to multiple schwannomas on peripheral nerves, which cause chronic pain.  


Scoliosis refers to a lateral (sideways) curvature of the spine, like an “S” shape. Severe curves can cause hips or shoulder bones to be different heights and therefore effect posture and balance. It is present in 10% of people with NF, but only less than 2% of the general population. A curve that is between 25-40 degrees is often treated with a special brace fitted by an orthopaedic specialist. Braces correct the bend in the spine but are hard, hot and uncomfortable and poorly tolerated by most people. Moderate cases of scoliosis may be treated with surgery where metal rods and wires correct the curve in the spine.  

Severe cases, (called Dystropic Scoliosis) is only found in people with NF1 and occurs between the ages of 6-10.  


Strabismus is the medical term used to refer to “turned”, “lazy” or “crossed” eyes. Essentially this means that when looking at an object both eyes will point in different directions. While this is a common condition it can be associated with an underlying cause warranting further investigation in some cases.


A medical term used to describe ringing in the ears



Vestibular Schwannomas

Also known as an acoustic neuroma, is a tumour that can form on the nerve that takes sound and balance information to the brain (8th cranial nerve).