Choroid plexus papilloma (CPP) is a WHO Grade I benign intraventricular tumor originating from the choroid plexus epithelium lining the ventricular system. It most commonly occurs in the lateral ventricle (trigone) in children and in the fourth ventricle in adults. The tumor characteristically demonstrates lobulated 'cauliflower-like' morphology and intense homogeneous enhancement. Hydrocephalus develops due to CSF overproduction — this is communicating type and may coexist with obstructive component. The tumor is the most common cause of intraventricular tumors in children under 1 year of age.
Age Range
0-20
Peak Age
2
Gender
Equal
Prevalence
Rare
Choroid plexus papilloma develops from choroid plexus epithelial cells responsible for CSF production in the ventricular system. Normal choroid plexus is covered by villous single-layer cuboidal-columnar epithelium with rich vascular stroma. The tumor mimics this normal structure but forms hyperplastic villous projections creating 'cauliflower-like' lobulated morphology. The tumor's rich vascular stroma is the primary reason for intense homogeneous enhancement on CT and MRI — each villous projection contains a capillary network and fenestrated endothelium, and contrast agent freely leaks through these permeable capillaries. Hydrocephalus develops through two mechanisms: (1) communicating hydrocephalus — tumor cells produce 5-10 times more CSF than normal choroid plexus, exceeding absorption capacity of arachnoid granulations; (2) obstructive component — the large tumor size may obstruct ventricular foramina (Monro, Luschka, Magendie). The intermediate signal on T2-weighted images reflects the short T2 time of dense cellular and vascular components in villous structures. Absence of prominent diffusion restriction on DWI indicates cells are not tightly packed with wide extracellular space between villous structures — different from marked restriction in choroid plexus carcinoma.
A lobulated 'cauliflower-like' intraventricular mass with intense homogeneous enhancement in the lateral ventricle trigone (children) or fourth ventricle (adults) together with communicating hydrocephalus — the classic triad of choroid plexus papilloma. This triple combination is nearly diagnostic.
On post-gadolinium T1-weighted images, the tumor demonstrates intense and homogeneous enhancement — the most defining finding of choroid plexus papilloma. Lobulated surface contours become more clearly visible after enhancement. Enhancement is homogeneous throughout the entire tumor with no necrotic or non-enhancing areas expected (unlike carcinoma). CSF surrounding the intraventricular mass remains dark without enhancement, maximizing tumor-CSF contrast.
Report Sentence
Intense and homogeneous enhancement is observed in the intraventricular mass following contrast administration.
Choroid plexus papilloma shows iso- to hypointense signal relative to brain parenchyma on T2-weighted images. Lobulated 'cauliflower-like' morphology is prominent. Flow voids within and around the tumor may be visible — indicating rich vascularity. Tumor-CSF contrast is good as surrounding CSF is hyperintense.
Report Sentence
A lobulated mass lesion demonstrating iso- to hypointense signal relative to brain parenchyma with intratumoral flow voids is observed in the intraventricular space on T2-weighted images.
On non-contrast CT, choroid plexus papilloma appears as an iso- to slightly hyperdense mass relative to brain parenchyma. Lobulated contours may be detected. Calcification is present in 20-25% of cases (punctate or coarse). Hydrocephalus — communicating type with disproportionately enlarged ventricles. Intense homogeneous enhancement on contrast CT.
Report Sentence
An iso- to slightly hyperdense lobulated mass is observed in the intraventricular location on non-contrast CT with findings of communicating hydrocephalus.
Lobulated intraventricular mass showing iso- to hypointense signal relative to brain parenchyma on T1-weighted images. Lobulated 'cauliflower-like' morphology may be detected even before contrast. Being surrounded by CSF provides tumor-CSF contrast.
Report Sentence
A lobulated mass lesion demonstrating isointense signal relative to brain parenchyma is observed in the intraventricular location on T1-weighted images.
Choroid plexus papilloma does not show prominent diffusion restriction on DWI — ADC values are normal or mildly decreased. This finding is important for differentiation from marked diffusion restriction in choroid plexus carcinoma. ADC values >1.0 × 10⁻³ mm²/s generally support papilloma, <0.8 suggests carcinoma.
Report Sentence
No prominent diffusion restriction is observed in the intraventricular mass on DWI, with ADC values consistent with papilloma.
Communicating hydrocephalus findings are prominent on FLAIR: all ventricles are enlarged, periventricular transependymal edema shows hyperintense signal. Periventricular edema reflects increased CSF pressure and transependymal CSF leakage. The tumor itself shows intermediate signal on FLAIR.
Report Sentence
Communicating hydrocephalus and periventricular transependymal edema findings are observed on FLAIR.
Criteria
Located in the lateral ventricle trigone (atrium), the most common intraventricular tumor in children (especially <2 years). Slight left lateral ventricle predominance.
Distinct Features
May present with macrocephaly and bulging fontanelle. Communicating hydrocephalus prominent. Lobulated morphology and intense enhancement. Curative with total resection. Prognosis excellent (>95% 5-year survival).
Criteria
Located in the fourth ventricle, more common form in adults. Cerebellopontine angle extension may be seen.
Distinct Features
Obstructive hydrocephalus predominant (fourth ventricle outlet obstruction). Extension to cerebellopontine angle may create differential difficulty with ependymoma — homogeneous enhancement in papilloma, heterogeneous in ependymoma. Surgical approach posterior fossa craniotomy.
Criteria
Choroid plexus tumor showing increased mitotic activity (≥2 mitoses/10 HPF) but lacking frank anaplasia features. Intermediate form between Grade I papilloma and Grade III carcinoma.
Distinct Features
Imaging features largely similar to papilloma but may show slight heterogeneity and tendency for larger size. Slightly lower ADC than papilloma on DWI. Prognosis slightly worse than papilloma but much better than carcinoma. Total resection sufficient, adjuvant therapy controversial.
Distinguishing Feature
Ependymoma shows heterogeneous enhancement (intense homogeneous in papilloma), calcification more common, 'plastic' extension through Luschka foramina characteristic. Papilloma's lobulated 'cauliflower' morphology and homogeneous enhancement are differentiating.
Distinguishing Feature
Medulloblastoma arises from vermis (choroid plexus tumor is in ventricular lumen), shows marked diffusion restriction on DWI (absent in papilloma), enhancement may be heterogeneous. Age-wise medulloblastoma in older children (5-10 years), papilloma in <2 years.
Distinguishing Feature
Intraventricular meningioma may also show intense enhancement but typically in adults, lobulated morphology less prominent, dural tail may be present. T2 signal more variable in meningioma with different calcification pattern.
Distinguishing Feature
Central neurocytoma specifically located in lateral ventricle foramen of Monro region associated with septum pellucidum. Shows 'soap bubble' cystic areas and calcification. Enhancement is moderate (different from intense enhancement in papilloma). Typically in young adults.
Urgency
urgentManagement
surgicalBiopsy
Not NeededFollow-up
Postoperatif MR 24-72 saat içinde. Yıllık MR takip (nüks izlemi). Hidrosefali rezolüsyonunun değerlendirilmesi — cerrahi sonrası hastaların %70-80'inde hidrosefali düzelir.Treatment of choroid plexus papilloma is surgical resection, and total resection is curative. Preoperative hydrocephalus management may be needed (ventricular drainage or shunt). High bleeding risk during surgery due to tumor's rich vascularity — preoperative embolization may be considered. Recurrence rate is very low after total resection (2-5%). Hydrocephalus resolves postoperatively in 70-80% of patients; permanent shunt may be needed in 20-30%. Adjuvant therapy is controversial in atypical papilloma (Grade II). Five-year survival is >95% for Grade I. Prognosis is much worse in choroid plexus carcinoma (Grade III) requiring adjuvant chemoradiation.
Choroid plexus papilloma is curable with surgical resection (WHO Grade I). Preoperative embolization may be considered to reduce surgical bleeding due to rich vascularity. Hydrocephalus usually resolves after total resection. Malignant transformation (choroid plexus carcinoma) is rare but requires follow-up.