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An underestimation of pathologic diagnosis could be expected if disseminated choroid plexus tumors (CPTs) are diagnosed as lower grade tumors. Thus, molecular diagnosis using genome-wide DNA methylation profiling may be useful for clarifying the malignant potential of the tumor entity. Herein, we report a 2.7-year-old girl of pathologically atypical choroid plexus papilloma with intracranial dissemination. She was treated without radiotherapy and has been well, without recurrence for 32 months following the diagnosis. Subsequently, after a year from the diagnosis, T-stochastic neighbor embedding analysis was performed on methylation data of the case and compared with those of reference data of CPTs, revealing that the case was separated from the cluster of "Plexus tumor subclass pediatric B," which includes a majority of choroid plexus carcinomas with the worst prognosis of these entities, and was categorized into the cluster of "Plexus tumor subclass pediatric A" consisting of choroid plexus papilloma and atypical choroid plexus papillomas diagnosed pathologically. Our case indicates the clinical significance of molecular confirmation for diagnosis among CPTs, particularly lower grade tumors with dissemination.

Introduction: Choroid plexus tumors are rare neuroectodermal tumors that arise from the choroid plexus. Choroid plexus papillomas (CPPs) represent the lowest grade of these types of tumors and have a WHO grade I designation. Despite their typical low grade, some CPPs can exhibit aggressive behaviors including parenchymal invasion and dissemination throughout the neuro-axis. Due to their association with the choroid plexus, patients with CPP commonly present with signs and symptoms of hydrocephalus and increased intracranial pressure. Case Presentation: A 2-year-old male presented in extremis with acute hydrocephalus and seizure. He was found to have a large left intraventricular mass with innumerable intraparenchymal and extra-axial cysts throughout his neuro-axis. A literature review revealed five similar disseminated CPP cases with innumerable lesions. This is the youngest reported patient with disseminated CPP and the first with multiple compressive lesions. Following cranial resection and thoracic decompression, the patient’s lesions have remained stable (2 years of follow-up). A literature search of the PubMed/Medline databases was performed using the search terms [“disseminated choroid plexus papilloma” OR “choroid plexus papilloma” OR “metastatic choroid plexus papilloma”] up to March 2021. Articles were then screened for similar patient radiographic presentation and histological diagnosis. To mitigate publication bias, referenced articles were utilized to identify other case reports and case series. Discussion/Conclusion: We describe a rare case of a lateral ventricle CPP with widespread leptomeningeal dissemination causing acute obstructive hydrocephalus and compressive myelopathy requiring cerebrospinal fluid diversion and intracranial resection followed by thoracic spine decompression. This case report serves to broaden knowledge of disseminated CPP and to encourage complete neuro-axis imaging for choroid plexus tumors. Additionally, we propose a naming paradigm refinement that includes radiographic characteristics.

Background While Ureaplasma parvum has previously been linked to the incidence of chorioamnionitis, abortion, premature birth, and perinatal complications, there have only been rare reports of invasive infections of the central nervous system (CNS) in adults. Owing to its atypical presentation and the fact that it will yield sterile cultures using conventional techniques, diagnosing U. parvum meningitis can be challenging. Case presentation We describe a case of U. parvum meningitis detected in an adult patient following surgical brain tumor ablation. After operation, the patient experienced epilepsy, meningeal irritation, and fever with unconsciousness. Cerebrospinal fluid (CSF) analysis showed leukocytosis (484 * 106 /L), elevated protein levels (1.92 g/L), and decreased glucose concentrations (0.02 mmol/L). Evidence suggested that the patient was suffering from bacterial meningitis. However, no bacterial pathogens in either CSF or blood were detected by routine culture or serology. The symptoms did not improve with empirical antibiotics. Therefore, we performed metagenomic next-generation sequencing (mNGS) to identify the etiology of the meningitis. Ureaplasma parvum was detected by mNGS in CSF samples. To the best of our knowledge, this case is the first reported instance of U. parvum meningitis in an adult patient in Asian. After diagnosis, the patient underwent successful moxifloxacin treatment and recovered without complications. Conclusions As mNGS strategies can enable the simultaneous detection of a diverse array of microbes in a single analysis, they may represent a valuable means of diagnosing the pathogens responsible for CNS infections and other clinical conditions with atypical presentations.

Infantile choroid plexus papilloma (CPP) associated with multiple peritumoral cysts is a rare variant of CPP, and clinical course and optimal management are largely unknown. A 9-month-old boy presented with a large solid tumor in the left lateral ventricle associated with multiple peritumoral cysts, arachnoid cysts, and hydrocephalus containing xanthochromic fluid with high protein content. Shrinkage of these cysts and resolution of hydrocephalus were achieved after total resection of the hypervascular solid part of the tumor. Histological examination confirmed the solid part of the tumor as CPP and showed that the wall of the peritumoral cysts consisted of reactive gliosis without neoplastic cells. Follow-up magnetic resonance imaging 12 months after surgery revealed that these cysts remained stable. CPP with nonenhancing peritumoral cysts can be managed by resection of only the solid part of the tumor without permanent cerebrospinal fluid diversion.

Choroid Plexus Tumours (CPTs) account for 1–4% of all brain tumours in children. Atypical choroid plexus papillomas (aCPPs) are a subset of these tumours, defined over a decade ago, yet no consensus exists on the optimal approach to their management. We conducted a retrospective analysis of all patients treated for CPTs at the Hospital for Sick Children between January 1, 2000, and December 31, 2018, and focused on patients with aCPP. Data extracted from the patient records for analysis included: demographic and clinical features, radiological imaging, surgical and adjuvant therapies, key pathological features, immunohistochemical staining for TP53 and tumour karyotype. Six of seven aCPP samples were profiled using Illumina HumanMethylationEPIC arrays and the top 10,000 most variably methylated probes were visualized using tSNE. Copy number inferencing was also performed. Twenty-nine patients were diagnosed with CPT, seven of whom had a diagnosis of aCPP as confirmed by histological review. Methylation profiling demonstrated that aCPPs clustered with both choroid plexus papillomas (CPPs) and choroid plexus carcinomas (CPCs). Complete resection of the tumour was pursued in all cases of aCPP and no patient received adjuvant therapy. All aCPP patients were alive at last follow up. This limited case series suggests that paediatric aCPP can be successfully managed with surgical resection alone, followed by a ‘watch and wait’ approach thus avoiding adjuvant therapies. A deeper understanding of the biology of aCPP is required to identify objective markers which can help provide robust risk stratification and inform treatment strategies.

Choroid plexus papillomas (CPPs) are primary neuroectodermal neoplasms that usually arise in the fourth ventricle in adults. In this study, we present 12 patients with CPP arising from the cerebellopontine angle (CPP-CPA) and/or of the cerebellomedullary angle (CPP-CMA) that were treated in our department. Patients who underwent surgery for the treatment for CPP-CPA/CMA from January 2004 to March 2020 were identified by a computer search of their files from the Department of Neurosurgery, Tübingen. CPPs were classified according to their location into type 1 (tumor portion only in the CPA,), type 2 (tumor portions only in the CMA), and type 3 (tumor portions both in the CPA and CMA). Patients were evaluated for initial symptoms, previous therapies in other hospitals, extent of tumor resection, recurrence rate, and complications by reviewing patient documents. Of approximately 1500 CPA lesions, which were surgically treated in our department in the last 16 years, 12 patients (mean age 42 ± 19 years) were found to have CPP-CPA/CMA. Five were male, and seven were female patients. Gross total resection was achieved in nine cases, and a subtotal resection was attained in three cases. Tumor recurrence in the same location after the first surgery in our hospital was observed in 2 patients after 15 and 40 months of follow-up, and in another patient, distant metastases (C3/4 and L3 levels) were observed. Surgical removal of CPP is the treatment of choice, but additional therapeutic options may be necessary in case of remnant tumor portions, recurrence, or malignant transformation. Supplementary Information The online version contains supplementary material available at 10.1007/s10143-021-01506-4.

To investigate the clinical experience and application value of endoscopic resection of lesions in and around the third ventricle using a transcortical expanded transforaminal transvenous transchoroidal approach with an endoport.Clinical data and follow-up results of seven patients who underwent the removal of lesions in the third ventricle and its adjacent area with an endoport-guided endoscopic system from January 2018 to December 2020 in the Department of Neurosurgery, Zhongshan Hospital Affiliated to Fudan University, were analyzed retrospectively. Two other patients from the Affiliated Pediatric Hospital of Fudan University and the Affiliated Hospital of Guizhou Medical University, respectively, were included in the analysis.A total of nine cases of third ventricle tumors were included in the study, including six women and three men, with an average age of 37.8 years (4-84 years old) and a follow-up time of 6-44 months. These nine tumor cases included two pilocytic astrocytomas, one diffuse midline glioma (H3 K27-altered), two craniopharyngiomas, two choroid plexus (CP) papillomas, one germinoma, and one pineal parenchymal tumor of intermediate differentiation. Total resection was completed in eight cases, with one near-total resection. There were no complications related to the surgical approach, such as epilepsy, aphasia, or hemiplegia.The endoscope transcortical expanded transforaminal transvenous transchoroidal approach using an endoport can safely and effectively remove third ventricle lesions. This approach can reach a wide area, from the anterior to the posterior third ventricle.

Objective Choroid plexus tumors (CPTs) are rare pediatric intracranial neoplasms, and mostly occur in the lateral ventricle. CPTs located in the infratentorial location are considered to be rare in the pediatric population. We present a series of eight patients treated in the last decade at our institution focusing on clinical presentations and their outcome after excision. Methods We performed an institutional retrospective review of patients who underwent surgical resection of infratentorial CPTs during the period from 2008 to 2017. Patients’ charts were reviewed for demographic data, clinical presentation, surgical treatment, and follow-up. Results There were eight patients (6 females and 2 males), with mean age for the cohort at presentation was 9.0 years. They represent 75% of 12 CPTs of all locations treated at the same period in our institution. These 8 infratentorial CPTs were in the fourth ventricle in seven, and in the cerebellopontine angle (CPA) in one. Seven patients had choroid plexus papillomas (WHO grade I) and 1 had an atypical choroid plexus papilloma (WHO grade II). Gross total resection was attempted in all patients. However, two of 3 patients with fourth ventricle floor invasion had subtotal resection with a thin layer of tumor left on the floor. The remaining 6 had a gross total resection. Six patients with preoperative hydrocephalus had a perioperative external ventricular drainage but none required permanent shunting after tumor resection. None showed recurrence/tumor progression without adjuvant therapy during the follow-up period of 20 months to 11 years. Conclusion Infratentorial dominance among pediatric CPTs in this series contradicts previous reports. Infratentorial CPTs are amenable to surgical resection. Unresected small residuals due to invasion to the fourth ventricle floor showed no regrowth during 2 to 3 years follow-up without adjuvant therapy. However, these patients with incomplete resection need watchful observations.

Background The coexistence of multiple sclerosis and intracranial neoplasms is very rare, and whether this occurrence can be explained by a causal relationship or by coincidence remains a matter of debate. Possible roles of the choroid plexus as a site of tumor cell invasion and lymphocyte infiltration into the central nervous system have been hypothesized in recent studies. Methods We describe a 13-year-old boy with concurrent multiple sclerosis and choroid plexus papilloma, then review the published literature with a focus on the pathophysiologic mechanisms of neuroinflammation in multiple sclerosis and the potential role of the choroid plexus in this process. Results A growing body of evidence suggests that both physical and functional dysregulation of the choroid plexus may be a common mechanism underlying the pathophysiology of central nervous system inflammation. Conclusions In multiple sclerosis, the choroid plexus could act as a gateway for lymphocyte entry from the peripheral blood into the central nervous system at its earlier stages. However, future studies are needed to identify whether structural alterations of the choroid plexus play a role in the pathophysiology of multiple sclerosis and to provide suitable models to determine their consequences.

BACKGROUND Atypical choroid plexus papilloma (CPP) is an uncommon World Health Organization grade II neuroepithelial intraventricular tumor that can occur in both children and adults. These tumors are usually identified in the fourth ventricle in adults and the lateral ventricles in children. They are rarely found in the spinal cord (synchronous or metastatic). We report the first case of an isolated lumbar grade II atypical CPP. CASE DESCRIPTION A 42-year-old man was admitted to the hospital because of back and leg pain. No urinary or rectal dysfunction was detected. Lumbar magnetic resonance imaging (MRI) showed a well-circumscribed, contrast-enhancing, intradural extramedullary mass at L2-3. He underwent L2 and L3 partial laminectomies for tumor resection and complete resection was achieved without causing neurological deficit. Histopathologic examination of the tumor resulted in a diagnosis of grade II atypical CPP. The Ki-67 staining index was 7%. No lesion was detected on postoperative craniospinal MRI. CONCLUSION Isolated lumbar atypical CPP in the lumbar region has not been previously reported. In the presence of a single spinal lesion, the diagnosis of CPP should be considered. Unlike metastatic and synchronous tumors, the pathogenesis of isolated choroid plexus tumors within the spinal canal has not been explained.

BACKGROUND To determine if histograms of ADC can be used to differentiate ventricular ependymomas, choroid plexus papillomas (CPPs), and central neurocytomas (CNCs). MATERIAL AND METHODS We retrospectively reviewed records from 185 patients from 1 January 2014 to 1 November 2018. We finally included a total of 60 patients: 36 (60.00%) had histologically confirmed ependymomas, 10 (16.67%) had CPPs, and 14 (23.33%) had CNCs, as determined by routine MRI scanning at 3.0T. The ADC histogram features were derived and then compared by Kruskal-Wallis test (they were not normally distributed). Bonferroni test was used to compare the 2 groups and then we determined the ROC. RESULTS Ependymomas had significantly higher mean, perc.01%, perc.10%, perc.50%, perc.90%, and perc.99% than CNCs. Ependymomas had significantly lower skewness than CNCs. Histogram metrics derived from mean, perc.01%, perc.10%, perc.50%, and perc.90% were significantly lower in the CNCs group than in the CPPs group. CPPs showed significantly lower skewness than CNCs. A threshold value of 86.50 for perc.50% to predict ependymomas from CNCs was estimated (AUC=0.97, sensitivity=97.20%, specificity=85.70%). Optimal diagnostic performance to predict CPPs from CNCs (AUC=0.96, sensitivity=100.00%, specificity=85.70%) was obtained when setting Perc.50%=84.00 as the threshold value. CONCLUSIONS The ADC histogram analysis may help to discriminate ependymomas, CPPs, and CNCs.

Choroid plexus tumours (CPTs) account for 2–5% of brain tumours in children. They can spread along the neuraxis and can recur after treatment. Little is known about the molecular mechanisms underlying their formation and only few high fidelity mouse models of p53-deficient malignant CPTs are available. We show here that c-MYC overexpression in the choroid plexus epithelium induces T-cell inflammation-dependent choroid plexus papillomas in a mouse model. We demonstrate that c-MYC is expressed in a substantial proportion of human choroid plexus tumours and that this subgroup of tumours is characterised by an inflammatory transcriptome and significant inflammatory infiltrates. In compound mutant mice, overexpression of c-MYC in an immunodeficient background led to a decreased incidence of CPP and reduced tumour bulk. Finally, reduced tumour size was also observed upon T-cell depletion in CPP-bearing mice. Our data raise the possibility that benign choroid plexus tumours expressing c-MYC could be amenable to medical therapy with anti-inflammatory drugs. Electronic supplementary material The online version of this article (10.1186/s40478-019-0739-x) contains supplementary material, which is available to authorized users.

Background Choroid plexus tumors are rare entities. Resection is the mainstay of treatment in grade I and grade II tumors and adjuvant treatment is usually reserved for the less frequent choroid plexus carcinoma (CPC). Outcome is not only related to their histological grade but also dependent on their size, location, and presence of often multifactorial disturbances of cerebrospinal fluid (CSF) circulation. Methods Retrospective analysis of 36 consecutive patients operated on a choroid plexus tumor at our institution in a mixed pediatric and adult population between 1991 and 2016. Results Twenty-one CPP, 11 atypical choroid plexus papillomas (aCPP), and four CPC were encountered in 17 children and 19 adults. Regardless of histological grading, gross-total resection (GTR) could be achieved in 91.7% of patients. Tumor recurrence (25.0%) was significantly associated with histological grading (p = 0.004), subtotal resection (p = 0.002), and intraoperatively evident zones of tumor infiltration (p = 0.001). Adjuvant therapy was performed in 19.4% of patients, mainly diagnosed with CPC. The 5-year overall survival rate was 95.2% for CPP and 100.0% for both aCPP and CPC. Survival was related to the extent of resection (p = 0.001), tumor progression (p = 0.04), and the presence of leptomeningeal metastases (p = 0.002). Even after resection, either ventricular or subdural shunting was required in 25.0% of patients. Conclusions We could confirm that GTR is crucial for treatment of choroid plexus tumors. Parenchymal tumor infiltration as detected intraoperatively was associated with the extent of resection and not limited to CPC. CSF disturbances mandating treatment may persist after resection.

Choroid plexus tumors (CPT) can present in the baseline magnetic resonance imaging (MRI) with lesions compatible with leptomeningeal dissemination. Therapeutic strategy in this condition is controversial. We present a case of an infant with CPP and significant diffuse leptomeningeal contrast enhancement at diagnosis, which spontaneously resolved after removal of the primary tumor. In these challenging cases, several aspects, such as histopathological/molecular diagnosis and close radiological follow-up, should be taken into account to avoid unnecessary treatments.

Background Choroid plexus tumors (CPTs) are rare tumors characterized by papillary and intraventricular growth. The young age of presentation of such tumors, especially in infants, and the lack of consensus on adjuvant therapy in case of atypical choroid plexus papilloma (aCPP) and choroid plexus carcinoma (CPC) create dilemma for the management of such tumors. We discuss the presentation, management, complications, and outcome in 15 patients (children 4 years of age and younger) and review pertinent literature. Methods We retrospectively analyzed the case records of all patients with CPTs who were operated in our institute from January 2010 to March 2018. We found 15 patients in the age group of 0–4 years of age. The variables analyzed include age, sex, presentation, location, surgical approach, extent of resection, intraoperative blood loss, percentage of blood loss, blood transfused, histopathology, postoperative complications, and outcome. Images were obtained from picture archiving and communication system, and patient details and follow-up were obtained from discharge summary, operative notes, and hospital records. Results Ten patients had choroid plexus papilloma (CPP), 2 patients had aCPP, and 3 patients had CPC. The mean age was 15.2 months, whereas the median age was 8 months (range, 40 days–4 years). The mean blood loss was 329 mL, whereas the median blood loss was 175 mL. There were a total of 5 deaths, including 3 patients with CPC and 1 each with aCPP and CPP. Conclusions CPTs are challenging tumors in infants and very young children because of the potential for massive blood loss. CPP is associated with lesser blood loss and favorable outcome compared with aCPP and CPC. Massive blood loss in CPC and aCPP can be life threatening as has been shown in our series. CPC has a rapid proliferation potential as shown in one of our cases. Attempts at decreasing vascularization of such tumors should be made by various methods, including preoperative embolization and neoadjuvant chemotherapy; however, a consensus on this is lacking.

Choroid plexus papillomas (CPPs) are benign but rare neuroepithelial neoplasms of the choroid plexus that represent the non-malignant form of a spectrum of tumors of the choroid plexus. The vast majority of CPPs present in children under 5 years of age. Some CPPs are diagnosed prenatally, but many of them reach a large size before diagnosis. CPPs typically present with signs and symptoms of hydrocephalus. Treatment of these tumors has traditionally been with surgical resection. Large CPPs in young children present a challenge due to risk of high blood loss during resection. Here, the authors describe the case of a 3-month-old presenting with hydrocephalus and a large CPP of the third ventricle that was managed with a staged strategy of embolization followed by a delayed resection, allowing the tumor to involute prior to surgery.

Background Choroid plexus tumors (CPTs) are intraventricular brain tumors predominantly arising in children but also affecting adults. In most cases, driver mutations have not been identified, although there are reports of frequent chromosome-wide copy-number alterations and TP53 mutations, especially in choroid plexus carcinomas (CPCs). Methods DNA methylation profiling and RNA-sequencing was performed in a series of 47 CPTs. Samples comprised 35 choroid plexus papillomas (CPPs), 6 atypical choroid plexus papillomas (aCPPs) and 6 CPCs plus three recurrences thereof. Targeted TP53 and TERT promotor sequencing was performed in all samples. Whole exome sequencing (WES) and linked-read whole genome sequencing (WGS) was performed in 25 and 4 samples, respectively. Results Tumors comprised the molecular subgroups “pediatric A” (N=11), “pediatric B” (N=12) and “adult” (N=27). Copy-number alterations mainly represented whole-chromosomal alterations with subgroup-specific enrichments (gains of Chr1, 2 and 21q in “pediatric B” and gains of Chr5 and 9 and loss of Chr21q in “adult”). RNA sequencing yielded a novel CCDC47-PRKCA fusion transcript in one adult choroid plexus papilloma patient with aggressive clinical course; an underlying Chr17 inversion was demonstrated by linked-read WGS. WES and targeted sequencing showed TP53 mutations in 7/47 CPTs (15%), five of which were children. On the contrary, TERT promoter mutations were encountered in 7/28 adult patients (25%) and associated with shorter progression-free survival (log-rank test, p=0.015). Conclusion Pediatric CPTs lack recurrent driver alterations except for TP53, whereas CPTs in adults show TERT promoter mutations or a novel CCDC47-PRKCA gene fusion, being associated with a more unfavorable clinical course.

Objective To present long-term follow-up of a consecutive single-institutional series of patients treated for choroid plexus tumors over 8 decades. Methods From 1939 to 2020, 59 children were treated for choroid plexus tumors. Median age at diagnosis was 1.7 years. Results Gross total resection was achieved in 51 patients (86%). Ten patients (17%) underwent >1 resection. During the first 4 decades of the study (1939–1979), 14 patients with plexus papillomas were treated. Operative mortality was 50%, with 6 of the remaining 7 patients experiencing excellent survival with follow-up periods of 41–81 years. In the last 4 decades (1980–2020), 38 patients had low-grade tumors, and all were alive at the latest follow-up (range, 0.5–39 years). Observed 5-year survival in this subgroup was 100% (n = 30), as was observed 10-year survival (n = 26). One of 7 (14%) patients with atypical choroid plexus papilloma and 3 of 31 patients (10%) with choroid plexus papilloma underwent a second resection owing to recurrent tumor. At last follow-up, 47 patients (80%) were alive; 45 (96%) had a Barthel Index score of 100 and 2 had a Barthel Index score of 50. Today 25 patients are adults (20–59 years old); 17 work full-time, 4 work part-time, and 4 are unable to work. Conclusions Low-grade choroid plexus tumors can be cured with gross total resection alone, with excellent long-term survival and functionality. The vast majority of survivors live independently as adults and work full-time. Recurrences are uncommon (8.7%), appear within the first few years after primary surgery, and can be treated with repeat resections.

Objective Choroid plexus tumours (CPT) are rare intraventricular tumours representing less than 0.5 % of brain tumours. The tumour is commonly located in the supratentorial region, but the location varies depending on the age. We present our experience of managing these tumours in a tertiary hospital. Methods Retrospectively, we reviewed our operative database and recruited 80 cases of CPT who underwent surgical treatment in our institute from 1995 to 2018. We analysed the factors affecting the outcome and the perioperative complications of the choroid plexus tumour. Results A total of 80 choroid plexus tumours were recruited in our retrospective review, of which 44 were choroid plexus papilloma (CPP), 13 were atypical choroid plexus tumours (ACPP), 23 were choroid plexus carcinomas (CPC). The mean age was 16.75 (SD 16.71) in the overall cohort. Males were found to be predominant in all tumour groups (M/F: 46/34). Headache was the most common symptom (52.5 %). Hydrocephalus was seen in 53.8 % of cases. The median overall survival was 89.88 months. Gross total resection was achieved in 62.5 % cases (n = 50/80), and near-total resection in 27. 5 % cases (n = 22/80). The median overall survival was 89.88 months. The median overall survival for CPP, ACPP, CPC was 106.83, 37.37, 36.19 months, respectively. Median Event-free survival was 65.83 months. A Cox regression analysis of predictors of overall survival of atypical CPP and CPC was done, in which age, sex, location, size, the extent of the resection, and complications were considered. The extent of the resection (p = 0.01) and the size (p = 0.02) were related to overall survival Conclusion CPT’s are the rare intraventricular tumours, which requires aggressive resection strategies. The extent of resection offers survival benefit based on the histological grades.

Background Choroid plexus papillomas (CPPs) are rare, usually benign, neoplasms originating in the central nervous system. In this study, we present the first case of a giant airway-obstructing CPP in the pharynx of a newborn. Case presentation A cystic mass located in the pharynx was noted in a fetus at the 29th week of gestation. Elective cesarean section was performed at the 38th week of gestation with successful intubation and ex utero intrapartum treatment. On computed tomography, there was a huge airway-obstructing cystic mass in the choana and pharynx. Elective surgery with total excision was performed, and histological examination confirmed the diagnosis of CPP. Conclusion We report the first case of an extracerebral airway-obstructing CPP in the pharynx of a newborn. Radiologic examinations are not enough for the diagnosis of CPPs, and complete excision of the tumor with histological confirmation is indispensable for accurate diagnosis and treatment.

Choroid plexus tumors are uncommon intraventricular tumors that develop from the choroid plexus of the central nervous system. Choroid plexus papillomas arising from the cerebellopontine angle have been reported to almost exclusively occur in adults and are rarely found in children.We report a systematic review conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines of SCOPUS and PubMed databases for case reports and case series of choroid plexus papillomas arising in the cerebellopontine angle in the pediatric population and discuss clinical presentation, imaging features, management options, and outcomes. We also report a case managed at our center.Ten cases of pediatric choroid plexus papillomas arising in the cerebellopontine angle were identified from the systematic review in addition to the case reported here, resulting in a total of eleven cases. The patients' median age was 8 years with a slight female sex predilection (1.2:1). Patients most commonly presented with headache, cerebellar signs, and cranial nerve palsies with median duration of symptoms at 4 months. All patients underwent surgical treatment with majority achieving gross total excision. No deaths were reported at median follow-up of 12 months. Complete neurologic recovery was attained in seven cases while partial recovery was seen in two cases.Choroid plexus papillomas found in the cerebellopontine angle in the pediatric population are extremely rare but they should be considered in the differential diagnosis. Complete surgical resection is the mainstay of treatment with excellent outcomes achievable in majority of patients.

The choroid plexuses (CPs), located in the brain ventricles, form an interface between the blood and the cerebrospinal fluid named the blood-cerebrospinal barrier, which, by the presence of tight junctions, detoxification enzymes, and membrane transporters, limits the traffic of molecules into the central nervous system. It has already been shown that sex hormones regulate several CP functions, including the oscillations of its clock genes. However, it is less explored how the circadian rhythm regulates CP functions. This study aimed to evaluate the impact of sex hormones and circadian rhythms on the function of CP membrane transporters. The 24 h transcription profiles of the membrane transporters rAbca1, rAbcb1, rAbcc1, rAbcc4, rAbcg2, rAbcg4, and rOat3 were characterized in the CPs of intact male, intact female, sham-operated female, and gonadectomized rats. We found that rAbcc1 is expressed in a circadian way in the CPs of intact male rats, rAbcg2 in the CPs of intact female rats, and both rAbcc4 and rOat3 mRNA levels were expressed in a circadian way in the CPs of intact male and female rats. Next, using an in vitro model of the human blood–cerebrospinal fluid barrier, we also found that methotrexate (MTX) is transported in a circadian way across this barrier. The circadian pattern of Abcc4 found in the human CP epithelial papilloma cells might be partially responsible for MTX circadian transport across the basal membrane of CP epithelial cells.

A 26-year-old man was referred with facial weakness, dysarthria, dysphagia, ophthalmoparesis and severely weak and wasted legs. His symptoms had begun when aged 20 with electric shock pains and paraesthesia in both feet progressing over 6 months to the lower calves. He then developed buttock numbness and occasional faecal incontinence. By age 22, he had diffuse lower limb weakness and wasting, with difficulty standing from a seated position and frequent tripping. He became wheelchair-dependent within 3 years. Over the same time period, he developed progressive facial weakness, bilateral ptosis, slurred speech, difficulty chewing and swallowing and lost 10 kg of weight. He reported hearing difficulty, and an audiogram showed high-frequency hearing loss. Important negatives included absence of upper limb symptoms, autonomic, cardiac, respiratory or cognitive dysfunction. He was from a non-consanguineous, Lithuanian background and the eldest of three siblings. He was born following a normal pregnancy and delivery, and motor development was normal. He had sustained a left corneal abrasion with visual impairment following an accidental chemical injury aged 14. During the initial investigation of his symptoms (age 23), he was found to have a choroid plexus lesion in the fourth ventricle. It was completely resected and histology confirmed benign choroid plexus papilloma WHO grade I. Postoperative neuro-oncology discussion deemed the lesion cured. He had bilateral ptosis, bilateral facial wasting and could not close his mouth against gravity (figure 1A). Visual acuity was reduced to perception of light on the left, 6/9 on the right. There was almost complete, complex ophthalmoplegia (figure 1B) without fatiguability. Trigeminal sensation was reduced. He could not achieve eyelid closure; frontalis, buccinator and orbicularis oris were symmetrically weak. His speech was dysarthric and his tongue was weak. His uvula was central with symmetrical palatal movement, but the gag reflex was reduced. Figure 1 Clinical examination at age 26. …

Choroid plexus papillomas (CPPs) are typically benign tumors that can occur in any age group but are more commonly found in pediatric patients. Although these tumors are benign, there are several reports in adult patients of distant metastases present either at the time of diagnosis or occurring months to years after initial resection. Here, the authors report the case of a 14-year-old boy who presented with symptoms of elevated intracranial pressure due to obstructive hydrocephalus that was caused by a large fourth ventricular mass. Preoperative imaging included a full MRI of the spine, which revealed an intradural lesion that encased the distal sacral nerve roots at the tip of the thecal sac and was concerning for a drop metastasis. The patient underwent gross-total resection of both the fourth ventricular and sacral tumors with histology of both lesions consistent with benign CPP (WHO Grade I). In addition, the authors review prior reports of both pediatric and adult patients in whom benign CPPs have metastasized with either benign or atypical pathology found at a distant site. Taking into account this unusual case and reports in the literature, patients with even benign CPPs may warrant initial and routine follow-up imaging of the total neural axis in search of the rare, but possible, occurrence of drop metastasis.

Chlamydia trachomatis (CT) and the Chlamydophila species (CS) Chlamydophila pneumoniae (CPn), and Chlamydophila psittaci (CPs) are suggested to induce autoantibodies causative of several human autoimmune disorders like rheumatoid arthritis and systemic lupus erythematosus (SLE). The aim of the present study was therefore to identify cellular protein interaction partners with antisera to CT (α-CT) or CS (α-CS) and to identify functional consequences of such interaction in vitro. As detected with a commercial first trimester human prenatal brain multiprotein array (hEXselect, Engine, Germany), the most frequent interaction partner with both α-CT and α-CS was the ribosomal small subunit protein RPS27a. This could be confirmed by Western blot analysis with a recombinant RPS27a sample. In addition, immunocytochemistry with both antisera in the human choroid plexus papilloma cell line HIBCPP revealed a granular cytoplasmic staining, and Western blot analysis with whole-cell protein samples of HIBCPP cells revealed both antisera to label protein bands of different molecular weights and intensity. By 2D Western blot analysis and mass spectrometry, one of the protein spots interacting with α-CT could be identified as the RPS27a. Finally, two different methods for the detection of protein synthesis activity, the SUnSET technique and an HPG fluorescence assay revealed both antisera to cause reduced translational activity in HIBCPP cells. Together with previous findings of RPS27a as an autoimmune target in a mouse model of systemic lupus erythematosus (SLE), these results suggest that infections with CT and/or CS could induce SLE-associated immune modifications. However, direct evidence for a pathogenic role of these interactions for SLE demands further investigations.

Background Atypical choroid plexus papilloma (APP) is a rare, newly introduced entity with intermediate characteristics. To date, few reports have revealed the magnetic resonance (MR) findings. Purpose To analyze the clinicopathological and MR features of APP. Material and Methods The clinicopathological data and preoperative MR images of six patients with pathologically proven APP were retrospectively reviewed. The MR features including tumor location, contour, signal intensity, degree of enhancement, intratumoral cysts, and necrosis; and flow voids, borders, peritumoral edema, and associated hydrocephalus were analyzed. Results The APP were located in the ventricle (n = 4) and cerebellopontine angle (CPA, n = 2). Tumor dissemination along the spinal subarachnoid space was found in one patient. The tumors appeared as milt-lobulated (n = 5) or round mass (n = 1), with slightly heterogeneous signals (n = 5) or mixed signals (n = 1) on T1-weighted and T2-weighted images. Heterogeneous and strong enhancement were found in five cases on contrast-enhanced images. Three of four intraventricular tumors had a partly blurred border with ventricle wall. Four tumors had mild to moderate extent of surrounding edema signals. A slight hydrocephalus was seen in four patients. Incomplete capsule was seen in four tumors at surgery. Histopathologically, mild nuclear atypia was seen in all tumors with a mitotic rate of 2–5 per 10 high-power fields. Conclusion APP should be included in the differential diagnosis when an intraventricular or CPA tumor appearing as a multi-lobulated solid mass with slight heterogeneity, heterogeneous strong enhancement, partly blurred borders, mild to moderate peritumoral edema, or slight hydrocephalus are present.

Choroid plexus tumors (CPT) are rare neoplasms accounting for 1–4% of all pediatric brain tumors. They are divided into choroid plexus papilloma (CPP), atypical choroid plexus papilloma (APP) and choroid plexus carcinoma (CPC). CPTs are known to primarily affect children less than 2 years of age. Gross total resection is the most important predictor of survival especially in CPC. Although small case series have been published, limited clinical data are available to describe treatment and outcome of CPTs. More clinical data would be necessary to complete the picture, particularly in populations that are not age limited. Here we share data from the two major hospitals in Cleveland to describe treatment and outcome of adult and pediatric patients. We performed a retrospective analysis of patients with CPT seen in Cleveland Clinic from 1990 to 2015 and at University Hospitals from 1994 to 2015. Results were compared to previously published historical controls. We identified 30 cases with CPT, including 22 pediatric and eight adult cases; 11 females and 19 males. The mean age at presentation was 12.4 years with a median age of 4.5 years (range 2 months–51 years). Gross total surgical resection was achieved in 22, subtotal resection in four, partial resection in two and unknown in two. The histology was CPP in 23 patients, two of whom developed recurrence requiring repeat resection and adjuvant therapy. Median event free survival (EFS) for CPP patients was 7.6 years. The histology was CPC in seven patients. All CPC patients were treated with adjuvant therapy. Median EFS of CPC patients was 4.4 years. Overall survival of all CPT patients was 100% with a median follow up of 7 years. A systematic literature review identified 1012 CPT patients treated from 1989 to 2013. The mean and median age of CPT patients was 13 and 3 years respectively. The median survival of 541 CPP patients was undefined vs. 2.7 years for the 452 CPC patients. The difference between the two populations was highly significant (p

Histological grading of choroid plexus tumors (CPTs) remains the best prognostic tool to distinguish between aggressive choroid plexus carcinoma (CPC) and the more benign choroid plexus papilloma (CPP) or atypical choroid plexus papilloma (aCPP); however, these distinctions can be challenging. Standard treatment of CPC is very aggressive and often leads to severe damage to the young child's brain. Therefore, it is crucial to distinguish between CPC and less aggressive entities (CPP or aCPP) to avoid unnecessary exposure of the young patient to neurotoxic therapy. To better stratify CPTs, we utilized DNA methylation (DNAm) to identify prognostic epigenetic biomarkers for CPCs.We obtained DNA methylation profiles of 34 CPTs using the HumanMethylation450 BeadChip from Illumina, and the data was analyzed using the Illumina Genome Studio analysis software. Validation of differentially methylated CpG sites chosen as biomarkers was performed using pyrosequencing analysis on additional 22 CPTs. Sensitivity testing of the CPC DNAm signature was performed on a replication cohort of 61 CPT tumors obtained from Neuropathology, University Hospital Münster, Germany.Generated genome-wide DNAm profiles of CPTs showed significant differences in DNAm between CPCs and the CPPs or aCPPs. The prediction of clinical outcome could be improved by combining the DNAm profile with the mutational status of TP53. CPCs with homozygous TP53 mutations clustered as a group separate from those carrying a heterozygous TP53 mutation or CPCs with wild type TP53 (TP53-wt) and showed the worst survival outcome. Specific DNAm signatures for CPCs revealed AK1, PER2, and PLSCR4 as potential biomarkers for CPC that can be used to improve molecular stratification for diagnosis and treatment.We demonstrate that combining specific DNAm signature for CPCs with histological approaches better differentiate aggressive tumors from those that are not life threatening. These findings have important implications for future prognostic risk prediction in clinical disease management.

Background Histological grading of choroid plexus tumors (CPTs) remains the best prognostic tool to distinguish between aggressive choroid plexus carcinoma (CPC) and the more benign choroid plexus papilloma (CPP) or atypical choroid plexus papilloma (aCPP); however, these distinctions can be challenging. Standard treatment of CPC is very aggressive and often leads to severe damage to the young child’s brain. Therefore, it is crucial to distinguish between CPC and less aggressive entities (CPP or aCPP) to avoid unnecessary exposure of the young patient to neurotoxic therapy. To better stratify CPTs, we utilized DNA methylation (DNAm) to identify prognostic epigenetic biomarkers for CPCs. Methods We obtained DNA methylation profiles of 34 CPTs using the HumanMethylation450 BeadChip from Illumina, and the data was analyzed using the Illumina Genome Studio analysis software. Validation of differentially methylated CpG sites chosen as biomarkers was performed using pyrosequencing analysis on additional 22 CPTs. Sensitivity testing of the CPC DNAm signature was performed on a replication cohort of 61 CPT tumors obtained from Neuropathology, University Hospital Münster, Germany. Results Generated genome-wide DNAm profiles of CPTs showed significant differences in DNAm between CPCs and the CPPs or aCPPs. The prediction of clinical outcome could be improved by combining the DNAm profile with the mutational status of TP53. CPCs with homozygous TP53 mutations clustered as a group separate from those carrying a heterozygous TP53 mutation or CPCs with wild type TP53 (TP53-wt) and showed the worst survival outcome. Specific DNAm signatures for CPCs revealed AK1, PER2, and PLSCR4 as potential biomarkers for CPC that can be used to improve molecular stratification for diagnosis and treatment. Conclusions We demonstrate that combining specific DNAm signature for CPCs with histological approaches better differentiate aggressive tumors from those that are not life threatening. These findings have important implications for future prognostic risk prediction in clinical disease management. Electronic supplementary material The online version of this article (10.1186/s13148-019-0708-z) contains supplementary material, which is available to authorized users.

Background Choroid plexus papillomas (CPPs) are benign World Health Organization grade I tumors that comprise 2%–4% of all brain tumors among children and less than 1% of brain tumors in adults. Most adult cases occur in the fourth ventricle, with only 1 previous report describing an adult patient with a temporal horn CPP. Case Description We report a rare case of a temporal horn CPP presenting in an adult with seizures. We performed a minimally invasive subtemporal approach for gross total resection of the lesion. Conclusions CPP presenting in the temporal horn is rare among adults. We discuss the surgical nuances of the subtemporal approach for resection and review the literature regarding adult presentation of CPP and the treatment strategies for adult CPP.

In adults, partial damage to V1 or optic radiations abolishes perception in the corresponding part of the visual field, causing a scotoma. However, it is widely accepted that the developing cortex has superior capacities to reorganize following an early lesion to endorse adaptive plasticity. Here we report a single patient case (G.S.) with near normal central field vision despite a massive unilateral lesion to the optic radiations acquired early in life. The patient underwent surgical removal of a right hemisphere parieto-temporal-occipital atypical choroid plexus papilloma of the right lateral ventricle at four months of age, which presumably altered the visual pathways during in utero development. Both the tumor and surgery severely compromised the optic radiations. Residual vision of G.S. was tested psychophysically when the patient was 7 years old. We found a close-to-normal visual acuity and contrast sensitivity within the central 25° and a great impairment in form and contrast vision in the far periphery (40–50°) of the left visual hemifield. BOLD response to full field luminance flicker was recorded from the primary visual cortex (V1) and in a region in the residual temporal-occipital region, presumably corresponding to the middle temporal complex (MT+), of the lesioned (right) hemisphere. A population receptive field analysis of the BOLD responses to contrast modulated stimuli revealed a retinotopic organization just for the MT+ region but not for the calcarine regions. Interestingly, consistent islands of ipsilateral activity were found in MT+ and in the parieto-occipital sulcus (POS) of the intact hemisphere. Probabilistic tractography revealed that optic radiations between LGN and V1 were very sparse in the lesioned hemisphere consistently with the post-surgery cerebral resection, while normal in the intact hemisphere. On the other hand, strong structural connections between MT+ and LGN were found in the lesioned hemisphere, while the equivalent tract in the spared hemisphere showed minimal structural connectivity. These results suggest that during development of the pathological brain, abnormal thalamic projections can lead to functional cortical changes, which may mediate functional recovery of vision.

Atypical choroid plexus papilloma (aCPP) is a newly introduced subtype of choroid plexus tumors (CPTs) defined by the World Health Organization (WHO) in 2007 and is characterized by intermediate characteristics between choroid plexus papilloma (CPP) and choroid plexus carcinoma (CPC). Currently, the available data describing the clinical features of aCPP in children are limited.We performed a retrospective review of 24 pediatric patients with CPTs in our institute and focused on the clinical, radiological and histopathological features of 9 patients with aCPP.The median age of aCPP patients was 12 (3-144) months, which was younger than the age of CPP patients (36 (5-132) months, P 0.05). Of the 9 aCPPs, there were 4 cases of giant masses in the cerebral hemisphere, which was significantly higher than that in CPPs (44.4 % vs 0.0 %, P 0.05). According to MRI analysis, cysts and necrosis (66.7 % vs 16.7 %, P 0.05), peritumoral edema (55.6 % vs 8.3 %, P 0.05) and blurred borders (55.6 % vs 8.3 %, P 0.05) were more common in aCPPs than in CPPs. T1WI isointense signals were mainly observed in aCPPs and CPPs (aCPP66.7 % vs CPP58.3 %, P0.05), while T2WI slightly low signals were more common in CPPs (CPP41.7 % vs aCPP0%, P 0.05); moreover, the tumor volume of aCPPs was significantly larger than that of CPPs (aCPP78.3 cm3 vs 8.4 cm3, P 0.05). For the DWI sequence scans, isointense signals were more common in aCPPs (aCPP77.8 %CPP25.0 %, P 0.05), while slightly low signals were more common in CPPs (CPP58.3 %aCPP0%, P 0.05). Both aCPPs and CPPs mainly showed homogeneously strong enhancement (aCPP66.7 % vs CPP91.7 %, P 0.05). Interestingly, 1 aCPP showed annular enhancement. For the pathological and immunohistochemical studies, the Ki67 proliferation index was significantly higher in aCPPs than in CPPs (13 % vs 6%, P 0.05), and the S-100(+)/Vim(+)/Syn(+) positive rate was higher in aCPPs (58.3 % vs 11.1 %, P 0.05).aCPP shows some distinctive clinical features compared with CPP, such as younger age, larger tumor size, more frequent necrosis and peritumoral edema, blurred borders, slightly low signals on T2WI and isointense signals on DWI, and a higher S-100(+)/Vim(+)/Syn(+) positive rate, which may provide more valuable evidence for differential diagnosis and clinical decisions surrounding aCPP.

Choroid plexus papillomas (CPPs) are uncommon, usually intraventricular, low-grade tumors, accounting for less than 1% of all intracranial neoplasms and 2-4% of brain tumors in children. Dissemination of CPPs to multiple levels of the neuraxis has been seldom observed. Thus far, only 26 adult patients have been reported in the English language literature. With some exceptions, disseminated CPPs have been observed in adults and involved multiple sites along the cerebrospinal fluid pathways. Occasionally, intraparenchymal extension has been documented, and secondary involvement of the suprasellar region has been reported in only five patients. Postoperative treatment of CPPs has not been standardized. Most recommended therapies have been extrapolated from a series of atypical papillomas or carcinomas of the choroid plexus in children. We herein report a series of three patients of disseminated choroid plexus papillomas providing additional insights into this relatively rare entity.

Objective Extraventricular intraparenchymal choroid plexus tumors (CPTs) in the cerebral hemisphere are extremely rare. The aim of this study was to investigate the clinical characteristics, radiologic findings, and surgical outcomes of this atypical type of CPT. Methods The study comprised 6 patients with pathologically proven extraventricular intraparenchymal CPTs who were surgically treated at Qilu Hospital of Shandong University. The PubMed database was searched for similar cases published before January 2015, and these cases were reviewed. Results Patients were 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 commonly demonstrated a contrast-enhancing intraparenchymal mass with cysts; hydrocephalus was not observed in any cases. Subtotal resection and gross total resection were achieved in 1 (16.7%) and 5 (83.3%) cases, respectively. There were 3 cases (50.0%) of choroid plexus papilloma, 2 cases (33.3%) of atypical choroid plexus papilloma, and 1 case (16.7%) not otherwise specified. There was a low incidence of postoperative complications, and surgical outcomes of CPTs were satisfactory. Conclusions In contrast to typical lesions, extraventricular intraparenchymal CPTs in the cerebral hemisphere are rarely associated with hydrocephalus. Magnetic resonance imaging features are key 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.

Lesions of the choroid plexus represent approximately 5% of the neonatal brain lesions and usually correspond to two different aetiologies: Choroid Plexus Papilloma or Carcinoma. Antenatal manageme...

The object of this review is to describe the choroid plexus tumors (CPTs) occurring in the fetus and neonate with regard to clinical presentation, location, pathology, treatment, and outcome. Case histories and clinical outcomes were reviewed from 93 cases of fetal and neonatal tumors obtained from the literature and our own institutional experience from 1980 to 2016. Choroid plexus papilloma (CPP) is the most common tumor followed by choroid plexus carcinoma (CPC) and atypical choroid plexus papilloma (ACPP). Hydrocephalus and macrocephaly are the presenting features for all three tumors. The lateral ventricles are the main site of tumor origin followed by the third and fourth ventricles, respectively. CPTs of the fetus are detected most often near the end of the third trimester of pregnancy by fetal ultrasound. The extent of surgical resection plays an important role in the treatment and outcome. In spite of excellent survival, which is especially true in the case of CPP, surgical resection may carry significant risks in an immature baby. Given the neonatal low blood volume and increased vascularity of the tumors, there is potential risk for hemorrhage. Although advances in neurosurgical techniques have led to a greater degree of complete surgical resections, survival for the perinatal CPC group remains low even with multimodality therapies. Perinatal CPTs have variable overall survivals depending on degree of surgical resection and tumor biology. An increased understanding of the molecular features of these tumors may lead to improved therapies and ultimately survival.

Amyloid‐β transmission has been described in patients both with and without iatrogenic Creutzfeldt–Jakob disease; however, there is little information regarding the clinical impact of this acquired amyloid‐β pathology during life. Here, for the first time, we describe in detail the clinical and neuroimaging findings in 3 patients with early onset symptomatic amyloid‐β cerebral amyloid angiopathy following childhood exposure to cadaveric dura (by neurosurgical grafting in 2 patients and tumor embolization in a third). Our observations provide further in vivo evidence that cerebral amyloid angiopathy might be caused by transmission of amyloid‐β seeds (prions) present in cadaveric dura and have diagnostic relevance for younger patients presenting with suspected cerebral amyloid angiopathy. Ann Neurol 2019; 1–7 ANN NEUROL 2019;85:284–290.

Background Large vascular brain tumors pose an exceptional challenge in young children. Choroid plexus papilloma (CPP) is an example of a rare, often large and especially vascular neuroepithelial tumor that most commonly arises in children under 5 yr old. Although patients may be cured by total resection, this tumor poses significant surgical risks and challenges related to intraoperative hemostasis. Objective To describe our experience using a transcollation system during brain tumor surgery in a child to achieve hemostasis and minimize blood loss while preserving normal brain tissue. Methods A 3-yr-old girl presented following a fall and was found to have a giant CPP growing from the right lateral ventricle. Given the vascularity of the tumor and the low intravascular reserve in a small child, a transcollation device was used to reduce blood loss intraoperatively. Results Gross total resection was achieved with approximately 300 mL of blood loss without complications. The patient did well postoperatively. Imaging performed at 3 mo after resection revealed return of normal brain architecture. Conclusion Transcollation devices appear to be an effective and safe addition to the armamentarium of neurosurgical hemostatic options in intracranial tumor resection in which there is a high risk of intraoperative hemorrhage.

Background It is very rare for a choroid plexus tumor to occur intraparenchymally in the absence of a relation to the choroid plexus. Clinical Presentation A case of cerebral intraparenchymal choroid plexus tumor in a 30-year-old woman presenting with left hemiparesis is described. Brain magnetic resonance imaging depicted a large cystic mass in the right frontal lobe. Tumor resection was performed by right frontal craniotomy. No connection with the choroid plexus was observed during the operation. Histologically, the tumor exhibited a glandular structure with a papillary pattern suggesting a neoplasm of epithelial origin. Immunohistochemical analyses revealed the tumor as an atypical choroid plexus papilloma. Conclusion Immunohistochemical findings, especially regarding Kir7.1, are very important for the differential diagnosis of cerebral intraparenchymal choroid plexus tumors from metastatic tumors. The present case reveals that an atypical choroid plexus papilloma can occur intraparenchymally without an association with the choroid plexus. Intraparenchymal atypical choroid plexus papillomas may have previously been diagnosed incorrectly as metastatic adenocarcinomas of unknown origin.

The authors report an illustrative case of a purely endoscopic surgical approach to successfully remove a solid choroid plexus papilloma of the third ventricle in an infant. A 10-week-old male infant first presented with transient episodes of forced downward gaze, divergent macrocephaly, a tense anterior fontanel, diastasis of the cranial sutures, and papilledema. Brain MRI revealed a small, multilobulated contrast-enhancing mass situated within the posterior third ventricle, with resultant obstructive hydrocephalus. A purely endoscopic removal of the tumor was performed through a single right frontal bur hole. Intraoperatively, a unique vascular tributary was recognized coming from the tela choroidea and was controlled with coagulation and sharp dissection. Postoperative MRI confirmed complete tumor removal, and the tumor was classified as a choroid plexus papilloma. There has been no evidence of tumor recurrence over 42 months of follow-up. With this case report the authors intended to show that endoscopic surgery can be an additional tool to consider when planning a choroid plexus tumor approach. It seems to be of particular interest in selected cases in which there are concerns about the patient's total blood volume, as in infants with potential hemorrhagic tumors and when it is possible to preoperatively identify a single vascular pedicle that can be approached early in the surgery.

Pleuropulmonary blastoma (PPB) is a rare childhood tumor, often associated with germline DICER1 mutations and a risk for development of other benign and malignant tumors, a constellation termed DICER1 syndrome. A 1-year-old male was diagnosed with Type I PPB and screened regularly thereafter for detection of intrathoracic and intraabdominal disease. Ten months after diagnosis of PPB, he presented with headaches and vomiting. He was diagnosed with atypical choroid plexus papilloma, a lesion not previously reported with PPB. The presence of central nervous system symptoms in patients with PPB or a phenotype suggestive of DICER1 syndrome should prompt early intracranial imaging.