Choroid plexus carcinoma is a rare form of neoplasm which is predominantly noted in children. It is an intraventricular, central nervous system (CNS) tumour that is derived from the choroid plexus epithelium. Choroid plexus carcinoma is characterized by papillary and intraventricular growth.
As per the WHO (World Health Organization), choroid plexus tumours are classified under 3 main categories as follows:
- WHO grade I – Choroid plexus papilloma (CPP)
- WHO grade II – Atypical choroid plexus
- WHO grade III – Choroid plexus carcinoma
Choroid plexus carcinoma is the most severe form of malignancy among the 3 grades of choroid plexus tumors and thus it is important to differentiate the 3 grades of malignancy from each other for providing appropriate treatment.
Symptoms of Choroid Plexus Carcinoma
Symptoms of Choroid plexus carcinoma may include:
- Hydrocephalus with increased intracranial pressure in view of obstruction of normal flow of cerebrospinal fluid
- Excessive production of cerebrospinal fluid by the tumour itself
- Local expansion of the ventricles or spontaneous haemorrhage.
Other signs and symptoms of Choroid plexus carcinoma include:
- Increased head circumference
- Bulging fontanelles primarily in infants
- Delay in development
- Altered mental status.
Choroid plexus carcinoma generally affects children and it presents with symptoms of cerebrospinal fluid obstruction. Among the paediatric population, the most common site of involvement is the lateral ventricles followed by the fourth ventricle. When this condition affects the adult population, the pattern is reversed with the most common site of involvement being the fourth ventricle followed by the second ventricle. It has been noted that the third ventricle is the least common site of involvement irrespective of the patient's age. In rare cases, primary extra ventricular papilloma may occur at the cerebellopontine angle. In some cases, either both the lateral ventricles gets involved or multiple ventricles get involved.
Epidemiology of Choroid Plexus Carcinoma
Choroid plexus carcinoma is more common among children than in adults. The incidence rate of this condition in all ages is about 0.3 cases per million. The peak incidence is within mid teenage years. It accounts for less than 1% of primary intracranial neoplasms and upto 5% of paediatric brain tumors and about 20% of those in children aged below 1 year and younger. It may also have foetal and congenital relation.
The incidence ratio between choroid plexus papilloma and choroid plexus carcinomas is about 5:1. About 90% of all choroid plexus tumor in children are choroid plexus papilloma, 70% of which occur in children below 2 years. This condition does not have significant sex predilection.
Prognosis of Choroid Plexus Carcinoma
The prognosis for choroid plexus carcinoma is not very good as the tumor grows very rapidly and the 5 year survival rate is only 40%. Among the total number of tumors, two-third of them metastasize through cerebrospinal fluid, and some malignant cells might be present in the cerebrospinal fluid even before resection is done which increases the risk of spreading of cancer. Systemic metastasis is observed in patients who survived longer. Complete resection of the tumor is the only objective which increases the chances of survival and the overall prognosis also improves. However, the prognosis is life-threatening if complete resection is not done.
Causes of Choroid Plexus Carcinoma
Most cases of choroid plexus carcinoma are sporadic in nature. It has been seen that hereditary factors play a vital role in development of choroid plexus papilloma and carcinoma. Choroid plexus papilloma is usually seen in association with Aicardi syndrome, Down syndrome, von Hippel Lindau disease and neurofibromatosis type 2. Choroid plexus carcinoma can arise is association with hereditary cancer predisposition syndromes including Li-Fraumeni and rhabdoid predisposition syndrome with genetic mutation of TP53 and hSNF5/INI1/SMARCB1, respectively.
Diagnosis of Choroid Plexus Carcinoma
Diagnosis of choroid plexus carcinoma may involve the following procedures:
- Computerized Tomography or CAT Scans: It is a diagnostic procedure that uses computer technology with combination of x-rays to produce cross-sectional images of the brain.
- MRI or Magnetic Resonance Imaging: It is diagnostic procedure where large magnets, radiofrequencies and a computer are used to produce detailed images of the brain and spine.
- Biopsy: In some cases, a tissue sample is extracted from the tumor with a needle under sterile condition to confirm the diagnosis.
- Lumber Puncture or Spinal Tap: In this procedure, a special needle is placed in the lower back, into the spinal canal and the area around the spinal cord to remove the cerebrospinal fluid, which is then sent to the laboratory of further studies and investigation. The CSF is studied under specialized machines to determine if there are any tumor cells. In children, this procedure is carried out under sedation to ensure that the procedure is carried out efficiently.
Treatment of Choroid Plexus Carcinoma
Treatment modalities are designed to promote physical and psychological well-being and may differ based on the following factors:
- Age of the child, overall health and medical history of the child
- Location, size and type of the tumor
- Extent of the disease
- Level of tolerance to certain medications, therapies and procedures
- Pattern of progression of the disease
The most commonly used treatment modalities are:
- Surgical Intervention: Complete removal of the tumor through neurosurgery usually helps in the treatment of the condition successfully. Chemotherapy prior to the surgery may help in shrinking the tumor, which in turn aids in easy surgery. Radiation therapy post-surgery may be recommended based on the condition.
- Chemotherapy: Chemotherapy is a drug treatment that disrupts growth and development of cancer tells. Different drugs are used based on the severity of the condition. It may be administered orally as a pill; intramuscularly as an injection; intravenously into the blood stream or intrathecally into the spinal fluid with a needle.
Other modes of treatment may involve radiation therapy, acupuncture, massages, dietary changes etc.
Choroid plexus carcinoma is a fast growing malignant condition and is very severe in nature. The prognosis is not very promising as 5 year survival rate is only 40% along with higher risk of systemic metastasis in individuals who live longer. The only way to improve the prognosis is by completely resecting the tumor. It is a potentially life-threatening condition and hence, one must not delay in seeking medical attention for children in case any of the symptoms are observed.