Choroid Plexus Papilloma

Choroid plexus papilloma is a benign (grade 1) papillary neoplasm of the choroid plexus epithelium. It makes up about 0.5% of brain tumors, 2 to 4% of childhood brain tumors and 10 to 20% of tumors in the first year of life. In children it arises in the lateral ventricle (trigone), and in adults in the fourth ventricle or cerebellopontine angle.

Hydrocephalus results from overproduction of cerebrospinal fluid, ventricular obstruction and impaired absorption from hemorrhage. Atypical papilloma (grade 2, 2 or more mitoses in 10 high-power fields) recurs more often. After complete resection 5-year survival exceeds 90%. Associations: Aicardi syndrome and Li-Fraumeni syndrome (usually carcinoma). Complications: hydrocephalus, hemorrhage, recurrence after subtotal resection, and rarely malignant change or cerebrospinal fluid dissemination.

• Infants: macrocephaly, bulging fontanelle, vomiting, irritability, sunsetting eyes and developmental delay
• Older patients: headache, ataxia, papilledema and cranial nerve signs
• Seizures in a minority
• Red flags: acute deterioration from intratumoral hemorrhage and falling consciousness

1. Ultrasound in infants (an echogenic intraventricular mass), then MRI brain and spine with gadolinium: a lobulated "cauliflower" mass with avid homogeneous enhancement and flow voids.
2. CT: calcification in about 25%.
3. CT or MR angiography to identify the feeding vessel (anterior or posterior choroidal artery).
4. Histology: papillary fronds on fibrovascular cores covered by a single layer of cuboidal epithelium, TTR positivity, Ki-67 under 2%.
5. Spinal MRI for dissemination.

Differentials: choroid plexus carcinoma, ependymoma, meningioma, medulloblastoma, subependymoma and metastasis.

• Surgery is curative: gross total resection with early control of the feeding artery. Blood loss can be large in infants, so arrange cross-matched blood, consider preoperative embolization, and give tranexamic acid 10 mg/kg IV (maximum 1 g) before incision.
• Hydrocephalus: external ventricular drain, then endoscopic third ventriculostomy or a ventriculoperitoneal shunt if it persists after resection (10 to 20%).
• Subtotal resection: second-look surgery, otherwise observation.
• Atypical papilloma: resection, with radiotherapy 54 Gy in 30 fractions for residual disease in older children, and genetic testing for TP53.
• Prophylaxis: cefazolin 30 mg/kg IV (maximum 2 g) before incision in children, 2 g in adults.
• Perioperative analgesia: paracetamol 15 mg/kg orally or IV every 6 hours (maximum 1 g a dose).

Follow-up: MRI brain at 3 months, 6 months, then annually for 5 years, with spinal MRI if atypical. Counsel the family about shunt malfunction signs.