| Choroid plexus is a tissue complex composed of epithelium,stroma and blood supply.The stroma contains fibroblasts,inflammatory cells and abundant extracellular matrix.There are 4 choroid plexus in the human body,which are located in 2 lateral ventricles,the third ventricle and the fourth ventricle.The main physiological function of choroid plexus is to produce cerebrospinal fluid(CSF).Because the choroid plexus epithelial cells can express major histocompatibility complex(MHC)classes Ⅰ and Ⅱ,they are also considered to be related to the autoimmune inflammation of the central nervous system.Like the other tissues of the central nervous system,benign or malignant tumors may also arise from the choroid plexus.Choroid plexus tumors(CPTs)are usually sporadic without a clear etiology.Previous studies suggested that it might be associated with viral infection and chromosomal abnormality,and generally did not demonstrate genetic susceptibility.CPTs are rare intracranial neoplasms,which can also produce CSF.The lesions locate commonly in lateral ventricles and the fourth ventricle,rarely in cerebellopontine angle(CPA)and the third ventricle.CPTs account for only 0.3%-0.6%of all brain tumors in adults and 2%-5%in children.Moreover,clinical features of tumor differ between adult and pediatric groups.It has been found that the location of tumor is significantly correlated to the age of patients.Over 80%of supratentorial CPTs are found in patients younger than 20 years,while the infratentorial CPTs were distributed evenly in all ages.In children,the tumor is mostly seen in the lateral ventricle,and the left side is slightly more than the right side,while the adult tumor is more common in the fourth ventricle.The median ages at diagnosis for tumors in the lateral ventricle,third ventricle,fourth ventricle,and CPA are 1.5 years,1.5 years,22.5 years,and 35.5 years,respectively.The common symptoms of CPTs are related to increased intracranial pressure,including headache,papillae edema,nausea and vomiting,cranial nerve dysfunction,gait disorders and seizures.CPTs usually arise in company with hydrocephalus,which is the most prominent feature.It is attributed to the direct obstruction of CSF circulation by tumor growth and the functional disorders of CSF generation and absorption.Moreover,hydrocephalus sometimes was not effectively alleviated when tumors were surgically removed.The reason may be the normal pressure hydrocephalus due to a long duration of hydrocephalus leading to cerebral cortex atrophy and thinning as well as decreased ability of postoperative cerebral tissue recruitment.In addition,preoperative and surgical hemorrhage in the ventricular system and tumor secretion stimulates the choroid plexus,which results in impaired CSF absorption.CT and MRI are important methods for the diagnosis of CPTs.The typical imaging findings were:In CT scan,the lesions mostly show equal or slightly high density,some of them could be mixed density,and a few had calcification or cystic components.In the MRI scan,the border of tumor is usually clear and the signals are often uneven.The tumor mass is generally lobulated or circular with an irregular form.On T1 weighted images,the tumor is commonly hypointense or isointense to gray matter.Most showed a high signal and a few showed low signal intensity on T2 weighted images.A high signal and an equal or slightly high signal could be seen in the fluid attenuated inversion recovery sequence and diffusion-weighted imaging,respectively.The tumors are uneven and markedly contrast-enhanced following administration of gadolinium.Because the tumor is composed of the papillary protuberances of the choroid plexus,the granular mixed signals are seen on the MRI,which are the imaging features of the tumors.The tumor is often accompanied by obvious dilatation of the ventricles.The lesion can cause the compression and deformation of the surrounding brain tissue,and the shift of the middle line structure.CPTs were classified into choroid plexus papilloma(CPP,WHO Ⅰ),atypical choroid plexus papilloma(ACPP,WHO II)and choroid plexus carcinoma(CPC,WHO Ⅲ)according to WHO classification of tumors of the central nervous system.The majority of CPTs are benign neoplasms and the malignant CPC accounts for only 10%-20%.CPPs grow slowly and can be cured by completely surgical resection.Its 5-year survival rate is about 100%.Adjuvant radiotherapy and chemotherapy were not recommended in patients who did not receive gross total resection(GTR)because only a few recurred through the long-term observation and follow-up.An increased cell mitotic activity is found in ACPP as compared to CPP.Patients of ACPP with GTR only require the observation and a close follow-up rather than the adjuvant therapy.Chemotherapy and radiotherapy are necessary for cases with tumor dissemination,recurrence or those who did not receive GTR,and radiotherapy is only suitable for patients older than 3 years.It is difficult to achieve GTR for CPC patients because of the hypervascularity and invasiveness of the tumor.Even if tumor was resected completely,the patients with CPC still needed further comprehensive therapies due to their anaplastic and infiltrative features:rapid progression,recurrence,distant metastasis,and leptomeningeal seeding.Radiotherapy and chemotherapy are important adjuvant therapies,which were proven to prolong the overall survival effectively.Although surgical total removal of the tumor is not the ultimate goal of treatment,published studies have shown that total resection surgery could significantly improve the prognosis of patients with CPC.Therefore,the key of CPTs treatment is to choose the optimal surgical procedures.Although most CPTs are benign tumors,characteristics of tumor as abundant blood supply,adherence to posterior cranial nerves and location deep in ventricles bring neurosurgeons great difficulties.The GTR of tumor is sometimes difficult to achieve and accompanied by high incidences of postoperative complications related to the ventricle system such as postoperative hyperpyrexia,aseptic and bacterial meningitis,ependymal meningitis,cerebrospinal fluid leakage and subdural effusion.The investigation and analysis of the related risk factors will help us understand and prevent postoperative complications.In general,there is a peduncle connected the tumor with choroid plexus,where the vascular supply is usually located.The blood supply mainly comes from the anterior choroid plexus artery,the posterior choroid plexus,the medial or posterolateral artery and the posterior inferior cerebellar artery.In the design of operative approach,we should consider not only the damage to the functional area of brain but also the exposure of the tumor peduncle.Besides,CPTs occasionally appear in the positions outside the ventricles,presenting an intraparenchymal mass.A few cases have been reported that CPTs can grow in the positions outside the ventricles,such as pineal region,sellar region,suprasellar region,cerebellum,brainstem and cerebral hemisphere.It is generally believed that these atypical CPTs originate from extraventricular extension of choroid plexus,or ectopic development of the remaining choroid plexus tissues during embryonic development and metastasis.We also found several atypical CPT cases in the brain parenchyma during the process of clinical diagnosis and treatment.Their clinical manifestations were quite different from those of typical lesions.No signs of hydrocephalus were found in preoperative imaging examination,and it is difficult to distinguish these special types of choroid plexus tumors from other intracranial lesions,which brings great difficulties to neurosurgeons in the preoperative diagnosis.Moreover,there has been no systematic study so far on the similarities and differences in clinical,imaging,pathology,and treatment between this atypical CPTs and typical lesions.We believe it is necessary to collect the clinical data of these patients,discuss and summarize the features including clinical symptoms and radiological manifestations by the combination with previous articles.As such,we retrospectively analyzed the clinical information including age,gender,tumor pathology,tumor size,hydrocephalus,and postoperative complications of 34 CPTs who were surgical treated and pathologically confirmed between January 2003 and December 2013 in our institution to compare the similarities and differences between the pediatric and adult groups,to analyze the risk factors of hydrocephalus and to investigate the risk factors of surgical complications.Then,we are the first to systematically describe the clinical characteristics of extraventricular intraparenchymal CPTs in cerebral hemisphere.This study will help us comprehensively study the clinical,radiologic,and pathological features of CPTs,in order to reduce the incidence of postoperative complications and improve the therapeutic effect.In addition,we are able to deeply understand the clinical characteristics of these atypical extraventricular intraparenchymal CPTs.Meanwhile,it provided the theoretical basis for neurosurgeons to diagnose correctly and to choose the optimal treatment,which benefits the patients.PART I.Clinical characteristics of choroid plexus tumorsObjectTo summarize the clinical characteristics of choroid plexus tumors(CPTs),compare the similarities and differences of clinical features between pediatric and adult patients and analyze related factors of hydrocephalus.MethodsCase records of 34 CPT patients who were pathologically confirmed between January 2003 and December 2013 in our institution were reviewed and analyzed.The corresponding statistical methods were used to compare the similarities and differences of the clinical characteristics between the children and adult CPTs and to analyze the related factors of hydrocephalus.ResultsThis series included 25 choroid plexus papillomas(CPP),5 atypical choroid plexus papillomas(ACPP),3 choroid plexus carcinomas(CPC)and 1 case not otherwise specified(NOS).Tumors were located in lateral ventricles in 8(23.5%),the fourth ventricle in 15(44.1%),the third ventricle in 1(2.9%),CPA in 4(11.8%),and cerebral hemisphere in 6(17.6%).The case series was composed of 21(61.8%)men and 13(38.2%)women.The mean age of the patients was 31.2 years(ranging from 7 months to 63 years).There were 12 pediatric(35.3%)and 22 adult patients(64.7%)in the study.There is no significant difference in tumor location between the pediatric and adult groups(P = 0.186).However,tumor in the pediatric patients mainly locates in lateral ventricles(41.7%)and tumor in the adult patients predominantly arises from the fourth ventricle(50.0%),which is consistent with previous studies.The mean maximum diameter of tumor in children was 4.52 cm compared to 3.39 cm in adult(P = 0.046);however,no significant difference was found in tumor volume between groups(P = 0.076).The percentage of hydrocephalus cases was 75.0%in the pediatric group compared to 31.8%in the adult group(P = 0.030).The patient age is not correlated to the tumor grade.There were 16 patients(47.1%)presenting with hydrocephalus.The majority of the patients in the hydrocephalus group were children(56.3%),while those in the non-hydrocephalus group were mainly adults(83.3%),and this difference was statistically significant(P = 0.016).There is no significant correlation between the occurrence of hydrocephalus and the patient gender and the tumor grade.Hydrocephalus was closely related to the tumor location(P-0.039).The mean maximum diameter and tumor volume of the hydrocephalus group were significantly larger than those in the non-hydrocephalus group(4.48 cm vs 3.00 cm,P = 0.005;74.17 cm3 vs 28.41 cm3,P = 0.032).ConclusionsIn the pediatric group,the mean maximum diameter of the tumor was longer and it’s more likely to be combined with hydrocephalus,as compared to the adult group.Hydrocephalus was significantly associated with age,tumor location and tumor size.PART Ⅱ.Treatment and postoperative complications of choroid plexus tumorsObjectTo summarize the therapeutic strategies of choroid plexus tumors(CPTs)and analyze the risk factors for the postoperative complications.MethodsCase records of 34 CPT patients who were pathologically confirmed between January 2003 and December 2013 in our institution were reviewed and analyzed.The corresponding statistical methods were used to analyze the risk factors for postoperative complications of CPTs.ResultsAll cases in our study were treated by microsurgery.Gross total resection(GTR),subtotal resection(STR),and partial resection(PT)were achieved in 29(85.3%),3(8.8%)and 2(5.9%)cases,respectively.Common postoperative complications contained fever in 27(79.4%),meningitis in 13(38.3%)and subdural effusions in 4 cases(11.8%).There were no significant correlations between postoperative fever and age(P = 0.192)or gender(P = 0.555),respectively.The postoperative fever was closely related to the tumor location(P = 0.039),and 57.1%of the patients in the non-fever group were located in positions outside the ventricle system.The maximum diameter of tumor(P = 0.189)and tumor volume(P = 0.232)did not affect the occurrence of postoperative fever.Similarly,the pathological type of tumor was not correlated with postoperative fever(P = 1.000).In addition,the prophylactic use of antibiotics does not effectively prevent the occurrence of postoperative fever(P =0.518).Patients with hydrocephalus seemed to be more likely to have fever after operation,and the average operation time in postoperative fever group was longer than that in the non-fever group(259.1 min vs 170 min),but the above two differences were not statistically significant(P = 0.051).There were no significant correlations between the postoperative meningitis and age(P=0.297)or gender(P =0.487),respectively.No significant correlation was found between the incidence of meningitis and tumor location(P = 0.052).The maximum diameter of tumor(P =0.155)and tumor volume(P = 0.118)did not affect the occurrence of postoperative meningitis.Similarly,the tumor grade was also not correlated with postoperative meningitis(P = 1.000).The preoperative hydrocephalus was not related to postoperative meningitis(P = 0.533).In addition,the prophylactic use of antibiotics does not effectively prevent the occurrence of meningitis after operation(P=0.318).The average operation time of the postoperative meningitis group was not significantly different from that of the non-meningitis group(275 min vs 219.5 min,P=0.533).Telephone interviews follow-up were done in 30 cases(24 choroid plexus papillomas(CPP),4 atypical choroid plexus papillomas(ACPP)and 2 choroid plexus carcinomas(CPC))among all 34 patients,in which 3 cases were out of contact and 1 case die during perioperative period.No tumor recurrence occurred in 24 cases of CPP,while 4 cases of ACPP and 2 cases of CPC further received radiotherapy but no chemotherapy.Among them,1 case of CPC patients died of tumor recurrence 1 year after the surgery,and the other patients had no obvious tumor recurrence.ConclusionsThe prognosis of CPTs is good on the whole.Surgery aiming total surgical resection is the key to successful treatment of CPTs.Postoperative complications of CPTs were common.There is a significant correlation between postoperative fever and tumor location.PART Ⅲ.Extraventricular intraparenchymal choroid plexus tumors in cerebral hemisphereObjectExtraventricular intraparenchymal choroid plexus tumors(CPTs)in the cerebral hemisphere are extremely rare.The aim of this study was to investigate the clinical characteristics,radiological findings and surgical outcomes of this atypical type of CPT.MethodsSix patients with pathologically proven extraventricular intraparenchymal CPT who were surgically treated in our institution were included and analyzed.The literature in the PubMed database regarding similar cases published before January 2015 was reviewed.ResultsThe present series consisted of 5(83.3%)men and 1(16.7%)woman,with an average age of 46.5 years.Symptoms and signs of CPT were usually associated with increased intracranial pressure and invasion of functional areas by tumor.Magnetic resonance imaging(MRI)commonly demonstrated a contrast-enhancing intraparenchymal mass with cysts,and hydrocephalus was not observed in any cases.Subtotal resection(STR)and gross total resection(GTR)were achieved in 1(16.7%)and 5(83.3%)cases,respectively.There were 3 cases(50.0%)of choroid plexus papilloma(CPP),2 cases(33.3%)of atypical choroid plexus papilloma(ACPP)and 1 case(16.7%)not otherwise specified(NOS).Along with low incidences of postoperative complications,the surgical outcomes of CPT were also satisfactory.ConclusionsIn contrast to typical lesions,extraventricular intraparenchymal CPTs in the cerebral hemisphere barely combined with hydrocephalus.MRI features play key roles in preoperative diagnosis;nevertheless,it is difficult to distinguish this atypical type of CPT from other lesions.Surgical removal of the tumor is safe and efficacious. |
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