Choroid Plexus Papilloma: Overview
맥락총 유두종: 개요
Introduction
Choroid plexus papilloma (CPP) is a rare, benign intraventricular tumor that originates from the epithelial lining of the choroid plexus. Representing less than 1% of all brain tumors, it is predominantly observed in the pediatric population, especially in children under the age of five. This blog post offers a deep dive into the epidemiology, pathophysiology, imaging characteristics, differential diagnosis, clinical presentation, and treatment strategies for CPP, about a specific pediatric case of a 4-year-old boy who presented with increasing episodes of headaches.
Case Overview
A 4-year-old boy presented with frequent and progressive headaches over several months. Brain MRI with and without contrast revealed an intraventricular lesion with a lobulated, leaf-like surface and strong homogeneous enhancement. The lesion was located in the posterior horn of the right lateral ventricle and appeared to arise from the choroid plexus. It was associated with mild ventricular dilation, but without evidence of periventricular edema, meningeal involvement, or obstructive hydrocephalus (See Figure).
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| Figure: Axial post-contrast T1-weighted MRI showing a vividly enhancing lobulated mass in the posterior lateral ventricle. |
Pathophysiology
CPP arises from the epithelial cells of the choroid plexus. It is classified as a WHO Grade I tumor, while its malignant counterpart, choroid plexus carcinoma (CPC), is classified as Grade III. An intermediate form, atypical CPP, exhibits certain malignant features but falls short of full CPC criteria.
These tumors can produce excessive cerebrospinal fluid (CSF), leading to hydrocephalus. Furthermore, both atypical CPP and CPC show a proclivity for CSF dissemination, causing drop metastases and subarachnoid tumor deposits.
Epidemiology
CPP is exceedingly rare, with an estimated annual incidence of 0.3 cases per million. It is most common during infancy, with peak incidence in children under one year of age. Approximately 10-20% of brain tumors in this demographic are CPPs. The mean age at diagnosis is 3.5 years, and there is a slight male predominance. Most CPPs are located in the lateral ventricles in children, particularly the atrium (trigone) region.
Clinical Presentation
Children with CPP typically present with signs of increased intracranial pressure due to obstructive or hypersecretory hydrocephalus:
Progressive headache
Nausea and vomiting
Papilledema
Seizures
Lethargy or behavioral changes
Focal neurological deficits such as hemiparesis
Rarely, CPPs may hemorrhage or shed tumor fragments into the CSF pathways, leading to secondary complications.
Imaging Features
CT Findings:
Iso- to hyperdense intraventricular mass
Intense homogeneous contrast enhancement
May contain calcifications (~25% of cases)
MRI Findings:
T1: Iso- to hypointense mass
T2: Variable intensity, often hypointense centrally
Post-contrast T1: Strong homogeneous enhancement
Flow voids may be seen due to vascularity
Differential Diagnosis
Choroid Plexus Carcinoma (CPC): More aggressive, infiltrative, often with necrosis and heterogeneous enhancement
Ependymoma: May extend through the foramina, often calcified and heterogeneous
Intraventricular Meningioma: Usually in adults, often dural-based
Metastatic Disease: Consider if systemic malignancy is present
Atypical Teratoid/Rhabdoid Tumor (ATRT): Occurs in very young children, is highly aggressive
Treatment
Complete surgical resection is the primary treatment. Gross total resection often leads to a cure in CPP. In cases of subtotal resection or atypical features, close follow-up with serial imaging is necessary.
Adjuvant therapies such as radiation or chemotherapy are generally reserved for atypical or malignant variants or in cases of CSF dissemination.
Prognosis
The prognosis for CPP is excellent with complete resection. Recurrence is rare but may occur, particularly in atypical variants. CSF spread should be evaluated with spinal MRI and CSF cytology in suspicious cases.
Quiz
1. What is the most prominent abnormality in this case?A. Dural thickening
B. Intraventricular lesion
C. Pachygyria
D. Microgyria2. Where is the lesion most likely arising from?
A. Thalamus
B. Ependyma
C. Periventricular white matter
D. Choroid plexus3. Is hydrocephalus present in this case?
A. True
B. False4. What best describes the morphology of the lesion?
A. Ill-defined, invasive
B. Rounded, well-circumscribed
C. Lobulated, leaf-like
D. Dural tail present5. Which diagnosis is most likely?
A. Ependymoma
B. Choroid plexus papillomaC. Intraventricular meningioma
D. Metastatic disease
6. What is the first-line treatment for CPP?
A. Radiation
B. Chemotherapy
C. Complete surgical resection
D. Observation only1. Answer: B. Intraventricular lesion. Explanation: MRI showed a vividly enhancing lesion within the lateral ventricle, typical of choroid plexus papilloma.
References
[1] Naeini RM, Yoo JH, Hunter JV. "Spectrum of choroid plexus lesions in children." AJR Am J Roentgenol, vol. 192, no. 1, 2009, pp. 32-40. [2] Safaee M, Oh MC, Bloch O, et al. "Choroid plexus papillomas: advances in molecular biology and understanding of tumorigenesis." Neuro Oncol, vol. 15, no. 3, 2013, pp. 255-267. [3] Sethi D, Arora R, Garg K, Tanwar P. "Choroid plexus papilloma." Asian J Neurosurg, vol. 12, no. 1, 2017, pp. 139-141. [4] Rickert CH, Paulus W. "Epidemiology of central nervous system tumors in childhood and adolescence based on the new WHO classification." Child's Nerv Syst, vol. 17, 2001, pp. 503-511. [5] Louis DN, Perry A, Reifenberger G, et al. "The 2016 World Health Organization Classification of Tumors of the Central Nervous System." Acta Neuropathol, vol. 131, 2016, pp. 803-820. [6] Sandberg DI, Edgar MA, Resnick DK. "Choroid plexus papilloma in children: diagnostic and therapeutic considerations." J Neurosurg Pediatr, vol. 1, 2008, pp. 268-272. [7] Wrede B, Liu P, Wolff JE. "Chemotherapy improves the survival of patients with choroid plexus carcinoma: a meta-analysis of individual cases with choroid plexus tumors." J Neurooncol, vol. 85, no. 3, 2007, pp. 345-351.
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