You are in: eMedicine Specialties > Radiology > BRAIN/SPINE Choroid Plexus PapillomaArticle Last Updated: Sep 23, 2008AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: Omar Islam, MD, FRCP(C), Assistant Professor of Radiology, Queen's University; Consulting Staff, Department of Imaging Services. Section Head, Division of Neuroradiology and Head & Neck Imaging, Kingston General Hospital and Hotel Dieu Hospital Omar Islam is a member of the following medical societies: American Society of Neuroradiology, Canadian Medical Association, Ontario Medical Association, and Radiological Society of North America Coauthor(s): Tariq A Butt, MD, Ryerson University Editors: Chi-Shing Zee, MD, Chief of Neuroradiology, Professor, Departments of Radiology and Neurosurgery, University of Southern California School of Medicine; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; C Douglas Phillips, MD, Professor, Departments of Radiology, Neurosurgery, and Otolaryngology, University of Virginia Health Sciences Center; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; James G Smirniotopoulos, MD, Professor of Radiology, Neurology, and Biomedical Informatics, Chairman, Department of Radiology and Radiological Sciences, Uniformed Services University of the Health Sciences Author and Editor Disclosure Synonyms and related keywords: choroid plexus papilloma, CPP, choroid plexus neoplasm, choroid plexus tumor, benign intracranial neoplasm, cerebral ventricle neoplasm, brain neoplasm, brain tumor INTRODUCTIONSection 2 of 12
  BackgroundChoroid plexus papilloma is a rare, slow-growing, histologically benign intracranial neoplasm that is commonly located in the ventricular system. PathophysiologyOn gross pathologic examination, choroid plexus papillomas appear as lobulated, encapsulated masses. They are neuroectodermal in origin and similar in structure to a normal choroid plexus. Choroid plexus papillomas arise from epithelial cells of the choroid plexus arranged as a multitude of papillary fronds resting on a delicate stroma of fibrovascular connective tissue. Choroid plexus papillomas are often associated with a vascular stalk connected to the choroid plexus, allowing mobility within the ventricular system. Blood breakdown products and high protein secretion result in hydrocephalus because of obstruction of cerebrospinal fluid (CSF) absorption at the level of the arachnoid granulations. CSF is produced at 4-5 times the normal rate, with resultant communicating hydrocephalus. Hydrocephalus may also result from direct tumor obstruction of the outlet of CSF flow from the ventricular system; this finding is especially true for tumors in the third ventricle, with resultant CSF outflow obstruction at the foramina of Monro. Bone formation and neuromelanin production may occur, but these are extremely rare. Doran et al described only 6 cases of bone formation,1 and Reimund et al described only 2 cases of neuromelanin production.2 Choroid plexus papillomas are not malignant; however, malignant evolution may occur, with an incidence of 10-30%. The lateral ventricles are the most common sites for malignant degeneration. With a clinical and histologic pattern of malignancy, which is characterized by invasion, mitotic figures, nuclear pleomorphism, necrosis, and metastasis, these tumors are classified as carcinomas.3, 4, 5 FrequencyInternationalPapillomas of the choroid plexus are rare, accounting for 0.4-0.6% of all intracranial neoplasms. In children, choroid plexus papillomas account for 1.5-6.4% of intracranial neoplasms. Mortality/MorbidityThe disease burden of choroid plexus papillomas can be significant, especially in young children. Morbidity is associated with developmental delay in 39% of pediatric patients, severe behavioral problems in 17%, and epilepsy in 48%. In a series by McEvoy et al, the 5-year survival rate was 100%.6 In a review by McGirr et al, tumors did not recur in half of the patients who underwent subtotal resection.7 Radiation therapy after surgical intervention usually is reserved for the treatment of choroid plexus carcinoma. If the tumor evolves into malignancy, the prognosis is dismal, with a 5-year survival rate of 26%. However, the histologic appearance may not be predictive of biologic behavior, because some highly anaplastic choroid plexus tumors can be clinically benign, whereas some histologically inactive tumors are invasive. The presence of mitotic figures, although rare in choroid plexus papillomas, may be predictive of the likelihood of both recurrence and malignant evolution. Such histologic findings in the surgical specimen should result in close clinical follow-up care of patients, especially in those whose postoperative images show findings of residual tumor. RaceNo racial predilection is reported in choroid plexus papilloma. SexThe male-to-female ratio of choroid plexus papilloma is 2.8:1, as Sarkar et al reported in a review of 23 cases.9 AgeMost choroid plexus papillomas appear as large tumors in young individuals. They are more common in children than in adults, with a mean patient age of 5.2 years. Of all choroid plexus papillomas, 20% occur in patients younger than 1 year old, and 85% occur in those younger than 10 years old. Choroid plexus papillomas may be discovered at birth. They account for approximately 40% of pediatric tumors that are present within the patient's first 60 days of life. AnatomyChoroid plexus papillomas may arise wherever a choroid plexus exists. In all age groups, the sites at which choroid plexus papillomas occur, in order of frequency, are the lateral ventricles (43%), fourth ventricle (39%), third ventricle (10%), and cerebellopontine angle (8%). Tumoral distribution varies between pediatric and adult patients. In children, most choroid plexus papillomas (80%) are located in the lateral ventricles. McEvoy et al described no predilection for the left or right side,6 whereas other authors, such as Hopper et al,10 report an increased incidence of tumors in the left lateral ventricle. About 16% of papillomas are found in the fourth ventricle, and 4% are found in the third ventricle. In those aged 0-10 years, the relative incidence of third ventricular papillomas approaches 30%. The fourth ventricle is the most common location of choroid plexus papillomas in adults. Choroid plexus papillomas can occasionally be bilateral or multiple. Interventricular extension can occur with a choroid plexus papilloma; this sign is not described with other interventricular tumors. Although uncommon, interventricular extension through the foramen of Munro, cerebral aqueduct, or foramen of Luschka or Magendie is a helpful diagnostic sign (see Image 5). Choroid plexus papillomas can arise in the cerebellopontine angle secondary to direct extension from tufts of choroid protruding through the foramen of Luschka. Extension into the foramen magnum may occur, with possible brainstem compression. Seeding can occur throughout the cerebrospinal axis; this usually results in a solitary metastasis from a lateral ventricular tumor in a child and in subarachnoid seeding to the spine from a fourth ventricular lesion in an adult. On rare occasions, widespread metastases from benign papillomas are observed. A few dozen cases of papillomas of a nonventricular origin are reported. These are possibly explained by an origin in the embryonic rests of choroid plexus. Extraventricular spread to the brain parenchyma, pineal region, or suprasellar area, as well as drop metastasis, is observed on occasion. Bone invasion may rarely occur; most commonly, this involves the petrous bone. Usually, involvement of bony structures implies the presence of CPC or malignant transformation of a benign papilloma. Carpenter et al described a single case report of extension to the cavernous sinus and invagination into the jugular foramen.11 Clinical DetailsSigns and symptoms In a review of 25 cases by McEvoy et al, the median duration of choroid plexus papilloma symptoms was 1 month, and approximately one third of patients presented within 2 weeks.6 The tumor's presence is often heralded by nonspecific signs and symptoms of increased intracranial pressure, which is present in 91% of patients, frequently in association with obstructive hydrocephalus. Vomiting is the most common sign in children. The presentation can also include hemiparesis, homonymous visual field defects, and generalized tonic/clonic and focal seizures. Gradin et al reported a case of sudden death in which the tumor involved the third ventricle, causing acute ventricular obstruction.12 Consider choroid plexus papilloma when an expansile, calcified, and vascular mass is closely associated with the ventricular system or cerebellopontine angle, especially in the presence of nonobstructive hydrocephalus. Surgical treatment As a result of their benign nature and slow growth, choroid plexus papillomas are amenable to complete surgical excision, with an expectation of total cure. Not surprisingly, a favorable long-term outcome is expected; the goals are a cure for all children and no requirement for adjuvant therapy. These goals are especially achievable if surgery can be performed early, before hydrocephalus or spontaneous hemorrhage cause irreversible damage.13 Despite advances in modern surgical techniques, such as the use of surgical microscopes, bipolar coagulation, stereotaxy, and image-guidance techniques, a significant risk of mortality and morbidity may be associated with surgical treatment. Malignant progression of choroid plexus papillomas has been occasionally reported. Frequency and extent of malignant progression were examined in a retrospective series of 124 primary choroid plexus papillomas by Jeibmann et al.14 The authors described recurrent tumor growth after gross-total resection in a small minority of their study group (6% of choroid plexus papillomas [World Health Organization (WHO) Grade I]) and 29% of atypical choroid plexus papillomas [WHO Grade II]).14 Malignant progression to choroid plexus carcinoma did occur in a small percentage of tumors (2 of 124 cases followed for a total period of 59 mo).14 Preferred ExaminationComputed tomography (CT) scanning and magnetic resonance imaging (MRI) are the investigative procedures of choice in the evaluation of choroid plexus papillomas. Because of the relatively noninvasive nature, ease, widespread availability, high reproducibility, and great contrast resolution of CT scanning and MRI, these examinations have supplanted all other methods of neuroimaging. With the addition of intravenously administered contrast material, the sensitivity of these imaging modalities approaches 100%. The multiplanar capability of MRI further aids in the characterization and localization of lesions. DIFFERENTIALSSection 3 of 12
Astrocytoma, Brain Brain, Metastases Ependymoma, Brain Epidermoid, Brain Hemangioblastoma, Brain Other Problems to Be ConsideredAcoustic neuroma (if tumor is in cerebellopontine angle) RADIOGRAPHSection 4 of 12
FindingsPlain radiography is not used to investigate choroid plexus papillomas. However, evidence of increased intracranial pressure may be noted. The presence of faint intracranial calcification in appropriate locations, which is observed in 4.1% of patients, may suggest the diagnosis. Degree of ConfidenceBecause of the low sensitivity and specificity of plain radiographs, CT scanning and MRI are the imaging studies of choice. CT SCANSection 5 of 12
FindingsThe advent of CT scanning has resulted in improvement in the detection and characterization of all intracranial masses, including choroid plexus papillomas. In choroid plexus papillomas, these tumors appear as well-marginated round or lobulated solid masses and are isoattenuating or hyperattenuating relative to normal brain parenchyma on nonenhanced scans. In as many as 24% of patients, the tumors may contain foci of calcification, which is readily demonstrated on CT scans, compared with MRI. Choroid plexus papillomas are strongly enhancing after the intravenous administration of contrast material. In children, choroid plexus papillomas can be heterogeneous in appearance because of the accumulation of CSF, blood, and blood products between the fronds and papillae. A heterogeneous appearance is a possible sign of malignancy. In adults, most choroid plexus papillomas are heterogeneous secondary to cystic and/or calcific degeneration. Associated findings include hydrocephalus, which may involve the lateral, third, and fourth ventricles to varying degrees. The presence of irregular margins should raise concerns about malignancy. Choroid plexus papillomas may have limited parenchymal invasion, which makes the distinction of the benign tumor from its malignant counterpart difficult. MRISection 6 of 12
FindingsMultiplanar imaging, which is possible with MRI, can be used to precisely localize and determine the extent of the choroid plexus papilloma, and thereby aid in surgical planning. MRI also has the advantage of eliminating artifacts of the posterior fossa, which can occasionally be problematic with CT scanning. MRI easily depicts local parenchymal invasion, which is occasionally present. MRI may be useful in distinguishing benign tumors from more aggressive or malignant choroid plexus tumors. Interventricular extension, an ancillary diagnostic sign of choroid plexus papilloma, is readily identified in the coronal plane. For these reasons, consider MRI the test of choice for the diagnosis of choroid plexus papilloma. Choroid plexus papillomas appear as heterogeneous masses, with or without cystic components; these may have intratumoral signal voids that correspond to a rich vascular supply or low-intensity areas that correspond to calcifications. On T1-weighted images, choroid plexus papillomas are slightly hypointense relative to gray matter in adults. In children, the masses are isointense. Small areas of high signal intensity are compatible with localized hemorrhagic components. On T2-weighted images, tumors in both adults and children have high signal intensity, which may approximate the signal intensity of CSF. After the injection of a paramagnetic contrast agent such as gadolinium-diethylenetriamine pentaacetic acid (Gd-DTPA), intense enhancement is observed. The superior imaging capability of MRI in the examination of the spinal canal may reveal evidence of seeding to the spinal subarachnoid space on rare occasions, particularly with posterior fossa tumors. Gadolinium-based contrast agents (gadopentetate dimeglumine [Magnevist], gadobenate dimeglumine [MultiHance], gadodiamide [Omniscan], gadoversetamide [OptiMARK], gadoteridol [ProHance]) have been linked to the development of nephrogenic systemic fibrosis (NSF) or nephrogenic fibrosing dermopathy (NFD). For more information, see the eMedicine topic Nephrogenic Fibrosing Dermopathy. ULTRASOUNDSection 7 of 12
FindingsUltrasonography may be useful in special circumstances, such as in neonates. The availability, portability, accuracy, low cost, and lack of a requirement for sedation make ultrasonography a valuable tool. In many instances, ultrasonography is the examination of choice for initial screening. Ultrasonographic evaluation may also be valuable in the postoperative assessment of the neonatal brain. In cases of choroid plexus papilloma, real-time ultrasonography demonstrates the presence of hydrocephalus. The tumors themselves appear as heterogeneous, highly echogenic intraventricular masses with irregular borders. Doppler ultrasonographic studies have shown pulsatile intratumoral vascular channels with biphasic flow. Occasionally, intratumoral cysts are identified; these appear as hypoechoic areas and are believed to represent areas of hydropic degeneration. ANGIOGRAPHYSection 8 of 12
FindingsThe blood supply to choroid plexus papillomas is derived from the choroid plexus. An enlarged anterior choroidal artery supplies tumors within the temporal horns of the lateral ventricles, whereas the posterior choroidal arteries supply masses in the atria or posterior horn. Branches of the posterior inferior cerebellar artery may supply tumors in the fourth ventricle. Angiographic signs may include the presence of many small spiral arteries; a meningioma-type blush with early tumoral circulation and persistent enhancement into the venous phase; displacement of vessels such as the internal cerebral veins; and evidence of ventricular dilatation. INTERVENTIONSection 9 of 12
Medical/Legal Pitfalls
Related Medscape topics: FURTHER READINGSection 10 of 12
Management of brain metastases: role of radiotherapy alone or in combination with other treatment modalities. MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
Choroid Plexus Papilloma excerpt Article Last Updated: Sep 23, 2008 | ||||||||||||||||||||||||||||||||||||||||||
