What is Choroid Plexus Papilloma?
Choroid plexus papillomas are uncommon tumors found in the central nervous system, making up less than 1% of all brain tumors. Even though these growths can appear at any age, about 70% of cases present in children under 2 years old. According to the World Health Organization, these tumors fall under grades I or II. However, the rarely occurring variant, choroid plexus carcinoma, is classified under grade III. Choroid plexus papillomas tend to be more common in the lower parts of the brain in adults and the upper parts in children. Those with these tumors often show symptoms of a condition called communicating hydrocephalus, which is caused by too much fluid in the brain. The outlook for patients with these benign (non-cancerous) tumors is generally good, with full removal of the tumor often leading to a cure.
What Causes Choroid Plexus Papilloma?
The exact cause of choroid plexus papillomas, a type of brain tumor, is unknown. It is believed that these tumors in newborns may be present at birth. Some research suggests a link between a virus called simian virus 40 (SV40) and the development of choroid plexus tumors. Other viruses such as BK virus and John Cunningham (JC) viruses have also been related.
Additionally, it was noticed that certain proteins, specifically SV40 large T antigen and TP53 and Rb proteins, were found in those with these types of tumors. The R248W mutation of TP53 is a frequent occurrence in choroid plexus tumors, however, the current evidence doesn’t support this mutation as a direct cause of the disease.
Risk Factors and Frequency for Choroid Plexus Papilloma
Choroid plexus tumors are rare brain growths that primarily affect children. They are the third most common brain tumor in children, following teratomas and gliomas, and make up 0.4 to 0.6% of all brain tumors. While adults can also be diagnosed with these tumors, they are more common in children; on average, children are diagnosed at 3.5 years old, and 70% of patients are under 2 years at diagnosis. For infants, these tumors are usually found in the left brain ventricles, while in adults, they’re most often found in the fourth ventricle of the brain.
- Choroid plexus tumors are rare, mostly seen in children.
- These tumors are the third most common type of brain tumor in children, after teratomas and gliomas.
- These tumors constitute 0.4 to 0.6% of all brain tumors.
- Adults may also get these tumors, but they generally affect children.
- The average age of diagnosis is 3.5 years, with 70% of patients diagnosed before the age of 2.
- In infants, these tumors typically show up in the left ventricles of the brain, but in adults, they often occur in the fourth ventricle.
Sometimes, Choroid plexus tumors are associated with certain syndromes like Aicardi syndrome, hypomelanosis of Ito, chromosome 9p duplication, and the von Hippel-Lindau syndrome.
Signs and Symptoms of Choroid Plexus Papilloma
Patients with choroid plexus papillomas often show symptoms due to increased pressure in the head. This is typically because of a condition called hydrocephalus. Common signs include headaches, feeling nausea or vomiting, fussiness, fatigue, and enlargement of the skull. Depending on where the abnormality is located, individuals may have symptoms like a stiff neck due to bleeding in the space around the brain, seizures, and focal neurological issues.
These neurological issues can involve sensory problems, weakness on one side of the body, issues with cranial nerves, and showing cerebellar signs like problems with balance and coordination. Hydrocephalus, or a buildup of fluid in the cavities deep within the brain, can happen because of a physical barrier to the flow of this fluid. Alternatively, it could be due to an overproduction of the fluid. Even though choroid plexus papillomas are benign or non-cancerous, they can grow rapidly.
In some cases, the only clinical issues may be cerebrospinal fluid leaking from the nose (CSF rhinorrhea) or spasms on one side of the face.
Testing for Choroid Plexus Papilloma
If a person has symptoms related to increased pressure inside the head or things hinting towards a growth in the brain, diagnostic imaging is used to find out what’s going on. This can include different types of scans such as an ultrasound, computed tomography (CT), or magnetic resonance imaging (MRI).
If the softer areas near the top of the baby’s skull (called fontanelles) are not yet closed, an ultrasound performed through the front fontanelle can help show if a reflective growth is present inside the brain fluid passages (ventricles). The growth might show a two-way blood flow all the time, which suggests abnormally arranged blood vessels. In fact, some of these growths have been spotted during an ultrasound scan before a baby is born.
Moving on to a CT scan, it might display a similar or slightly brighter growth within the brain’s connected fluid chambers, causing them to swell up. This condition, known as ventriculomegaly, is common when the fluid chambers get bloated due to excessive fluid accumulation, also called hydrocephalus. Around 25% of people with a growth in the brain known as choroid plexus papilloma would show tiny, scattered hardened deposits in the growth. The growths typically appear slightly irregular and intensely, though not uniformly, illuminated after a contrast-enhancing substance is given. The growth-enhancing substance also commonly shows that the blood vessel (choroidal artery) has enlarged in size.
An MRI scan looks at choroid plexus papillomas using special techniques. It usually shows distinct, fern-like masses inside the ventricles that may look less bright on T1-weighted sequences and brighter on T2-weighted sequences. The presence of dark spots on MRI, indicating active blood flow, is typical and, along with the rich blood vessel network, causes the growth to glow brightly after contrast enhancement. A technique called arterial spin labeling can help differentiate a benign papilloma from a malignant tumour. Some MRIs can show an intense color change suggesting increased blood flow to the growth along with enlarged choroidal arteries during a procedure called digital subtraction angiography.
Treatment Options for Choroid Plexus Papilloma
Medical experts don’t all agree on when best to perform surgery for choroid plexus papillomas, growths in the brain that are often discovered by surprise. Some suggest immediate surgical removal may be the best course, while others think it’s best to wait until symptoms appear, or scans show the tumor growing or causing hydrocephalus, a condition where fluid builds up in the brain.
The advantage of waiting is that if hydrocephalus occurs, it can make the tumor easier to remove, as it creates more space around the tumor. On the other side, waiting does carry risks: the growing tumor might cause specific symptoms based on its location, impact mental functioning, or cause bleeding and seizures.
Complete removal of these benign tumors is the preferred treatment in those exhibiting symptoms. Thanks to advancements in imaging technology, surgical methods, operating microscopes, and intensive care, the outcomes of such surgeries have significantly improved, and the cure rates are almost 100%. However, the surgery is not risk-free, especially in children, as there is a 12% risk of death due to the potential for heavy bleeding since these tumors have a rich blood supply. To reduce this risk, doctors can use a procedure to block the blood supply of the tumor before surgery.
Although rare, complications can occur after tumor removal, such as the accumulation of fluid in the brain that may require additional intervention. In some cases, chemotherapy can be used to prevent the tumor from coming back and to prolong survival. If the tumor grows back after incomplete removal, radiation can be applied to manage its size. Chemotherapy and other treatments are also necessary when the tumor spreads or becomes malignant.
New research has highlighted a potential role for a medication called bevacizumab in the management of choroid plexus tumors. More studies are needed to confirm this and find the most effective treatment method.
What else can Choroid Plexus Papilloma be?
When a person is being examined for a brain growth called choroid plexus papillomas, doctors must also consider other conditions that could mimic it. These could be other forms of tumors inside the brain ventricles, infections, or blood vessel abnormalities. These include but are not limited to:
- Ependymoma (a rare form of brain tumor)
- Central neurocytoma (a slow-growing tumor in the brain)
- Subependymal giant cell tumor (a benign brain tumor)
- Subependymoma (another type of brain tumor)
- Atypical choroid plexus papilloma (a variant of the same growth)
- Choroid plexus carcinoma (a cancerous form of the growth)
- Medulloblastoma (a cancerous brain tumor, often in children)
- Meningioma (a tumor that develops from the membranes enveloping the brain and spinal cord)
- Chordoid glioma (a rare form of brain tumor)
- Rosette-forming glioneuronal tumor (a rare type of non-cancerous brain tumor)
- Central nervous system lymphoma (cancer of the lymph tissue in the brain or spinal cord)
- Metastases (cancer that has spread from another part of the body)
- Colloid cyst (fluid-filled sac in the brain)
- Arachnoid cyst (fluid-filled sac that may develop in the brain or spinal cord)
- Epidermoid or dermoid cyst (slow-growing tumors that result from non-cancerous cells)
- Craniopharyngioma (a rare, slow-growing brain tumor)
- Infections like cysticercosis caused by a worm called Taenia solium
- Arteriovenous malformation (a disarray of blood vessels in the brain or body).
Remember, it’s a doctor’s responsibility to rule out other possible conditions before making a final diagnosis.
What to expect with Choroid Plexus Papilloma
Advancements in surgical and intensive care methods have greatly improved the outlook for patients with WHO grade I choroid plexus papillomas. Removing as much of the tumor as possible is linked with a longer period without disease progression and overall survival. It’s rare for these tumors to come back, and complete removal can sometimes cure the patient.
However, WHO grade II atypical choroid plexus papillomas are more likely to return than the grade I types. Even though it’s uncommon, there have been reports of tumors spreading to other parts of the brain and spinal cord, particularly in cases of choroid plexus carcinomas.
Possible Complications When Diagnosed with Choroid Plexus Papilloma
Kids who have prolonged symptoms of increased pressure within the brain, such as swelling of the optic nerve, damage to the optic nerve, and vision loss, may not see these symptoms fully go away after surgery. Some children may even keep having issues with memory and thinking, may experience bleeding in the brain, or may start having seizures.
For those with choroid plexus papillomas, a type of brain tumor, there’s a high risk of losing a lot of blood during surgery. There have also been cases where patients have experienced leakage of brain fluid through the nose after surgery.
Preventing Choroid Plexus Papilloma
Choroid plexus papillomas are uncommon, harmless brain tumors that mostly occur in children. They often lead to a condition called hydrocephalus, which can cause headaches, nausea, possible vomiting, or changes in a person’s awareness. Sometimes, these tumors can also cause specific physical symptoms like numbness, weakness, or facial nerve issues. It’s essential to have a head scan as soon as possible if these symptoms occur. An MRI is the preferred method. If the tumor can be completely removed through surgery, it typically leads to a cure. Because choroid plexus papillomas are harmless, additional treatment after surgery is usually not necessary.
