Paediatric atypical choroid plexus papilloma: is adjuvant therapy necessary?

INTRODUCTION: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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 tumors in adult and pediatric populations: the Cleveland Clinic and University Hospitals experience.

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 < 0.001). Kaplan-Meier survival curves comparing CPTs at Cleveland Clinic and University Hospitals versus a systematic literature review showed a statistically significant advancement in overall survival among the patients treated at Cleveland Clinic and University Hospitals. Our data are consistent with the literature review regarding epidemiology, clinical presentation, and treatment modalities but differed in regards to survival. Differences in survival may be related to different methods of data collection or details in patient care.

A French retrospective study on clinical outcome in 102 choroid plexus tumors in children.

The aim of this study was to review and describe therapeutic approaches in children with choroid plexus tumor (CPT) based on a nationwide series. The World Health Organization classification subdivides these rare tumors into three histological subtypes corresponding to three grades of malignancy: low grade (grade I) choroid plexus papilloma (CPP), intermediate grade (grade II) atypical choroid plexus papilloma (aCPP) and high grade (grade III) choroid plexus carcinoma (CPC). This retrospective study included 102 French children younger than 18 years, treated from 2000 to 2012: 54 CPP, 26 aCPP and 22 CPC. The 5 year overall survival was 100% in CPP, 96.2% in aCPP and 64.7% in CPC. In patients with localized disease, complete surgical resection was achieved in 48/52 CPP, 20/26 aCPP and 7/14 CPC. In this group, patients with complete surgical resection had better event free survival than patients with partial resection (88.9 vs. 41.6%). 28 patients (1 CPP, 6 aCPP and 22 CPC) had adjuvant chemotherapy. 2 aCPP and 9 CPC had radiotherapy. We underlined the need for a central histological review to accurately analyze clinical data; we reported a much higher overall survival for CPC than in most previous CPT series probably including atypical teratoid rhabdoid tumors. In our series, the 5 years overall survival in CPC (64.7%) was higher than event free survival (25.2%) and could be interpreted as a clue for the efficiency of adjuvant/salvage therapy even if the heterogeneity of applied treatments in this retrospective series does not allow for meaningful statistical comparisons.

[Choroid plexus tumours in childhood: Experience in Sant Joan de Déu hospital]. / Tumores de plexo coroideo en la infancia: experiencia en el hospital Sant Joan de Déu.

Choroid plexus tumours are rare, with a peak incidence in the first two years of life. The most common location is the lateral ventricle in children, while in adults it is the fourth ventricle. The most common clinical manifestation is the signs and symptoms of intracranial hypertension. They are histologically classified as plexus papilloma, atypical plexus papilloma, and plexus carcinoma. A review is presented on choroid plexus tumours treated in the Hospital Sant Joan de Déu between 1980 and 2014. A total of 18 patients have been treated. An analysis was made of the demographic, clinical, histological data, treatment, and recurrences. The treatment of choice is complete resection, accompanied by adjuvant therapy in carcinomas. In atypical papillomas, the use of adjuvant therapies is controversial, reserving radiation therapy for recurrences. Papillomas have a good outcome, whereas atypical papillomas and carcinomas outcome is poor.

[Choroid plexus tumour treatment at Hospital Infantil Niño Jesús in Madrid: Our experience over the last three decades]. / Tratamiento de los tumores de plexos coroideos en el Hospital Infantil Niño Jesús de Madrid: nuestra experiencia en las últimas tres décadas.

OBJECTIVE: To review childhood patients with choroid plexus tumors (CPT) who underwent surgery at Hospital Infantil Niño Jesús of Madrid since January 1981 to September 2014. MATERIAL AND METHODS: Registered charts were analyzed based on the epidemiology, tumor grade, clinical profile, location, dissemination characteristics, therapy, prognosis and complications. RESULTS: Seventeen childhood patients were recorded with CPT. Cases were distributed so that 9 cases were choroid plexus-papilloma (CPP) (52.9%), 2 cases atypical CPP (11.7%) and 6 cases choroid plexus-carcinoma (CPC) (35.2%). Age at diagnosis was less than 2 years in 14 of the 17 patients (82.3%) and the incidence was higher in males (82.3% of the cases). Gross total resection was performed in 16 patients (94.1%). Adjuvant treatment was used in 6 patients (all this cases with CPC) (35.2%). Two of the 17 patients died (11.7%), showing an incidence density of 0.01 deaths/year. CONCLUSIONS: Our case series is consistent with previous published in scientific literature regarding epidemiology, tumor grade, clinical presentation, radiological features and therapeutic approach. Gross total resection is considered the therapeutic gold standard for choroid plexus tumors. Chemotherapy and radiotherapy should be used as adjuvant treatment in CPC and recurrent or remaining atypical CPP.

Pre-operative embolisation of choroid plexus tumours in children. Part II. Observations on the effects on CSF production.

OBJECTIVE: Choroid plexus tumours are one of the few causes of hydrocephalus secondary to increased CSF production. Operative treatment aided by pre-op embolisation is being used in our institution as a primary option of treatment. Our aim was firstly to quantify the effects of embolisation on CSF production and secondly to assess whether the use of pre-operative embolisation would lead to reduction of CSF production thus reducing the need for CSF diversion procedures in the perioperative and long term. METHODS: From 1996 till 2009, 30 patients (mean age, 2.25 years) underwent surgical treatment for 24 choroid plexus papillomas and 6 choroid plexus carcinomas. Thirteen underwent pre-operative super-selective embolisation of the feeding vessels with Histoacryl glue. The need for CSF diversion-external ventricular drain (EVD)/shunt-was recorded together with the daily CSF production between the two groups (embolised: EMB+ vs. not embolised: EMB-) RESULTS: The embolisation was successful in 13 of 15 (86.6 %) patients. The average post-op daily CSF production between the EMB+ and EMB- groups was (67 vs. 135 ml/day; p = 0.005). EVD days in situ post-operatively was 7.9 vs. 12.1 (p = 0.033). However, the need for permanent CSF diversion was similar in both groups (five vs. six). CONCLUSION: We have established the safety of pre-operative embolisation as an adjunct to operative treatment of choroid plexus tumours. As we expected, this technique, by removing the tumour's blood supply, reduces the rate of CSF production. This has had a positive impact on the post-operative management of these patients. We cannot say the same for the need of permanent CSF diversion in our study.

Choroid plexus tumors in children: a population-based study.

BACKGROUND: Choroid plexus tumors are rare neoplasms that primarily occur in children. The use of the SEER (Surveillance, Epidemiology and End Results) database allows for the analysis of the relationship between prognostic factors and survival. METHODS: We analyzed the SEER database to select pediatric patients (<18 years old) with histologically confirmed diagnoses of choroid plexus papillomas (CPP; WHO Grade 0), atypical CPP (WHO Grade I) and choroid plexus carcinomas (CPC; WHO grade III). In univariate and multivariate analysis, we analyzed the relationship between demographic (age, gender, race, date of diagnosis) and treatment factors (extent of surgical resection, use of adjuvant radiation) on survival. RESULTS: Overall, 168 pediatric subjects with choroid plexus tumors were identified as follows: 75 cases of CPP, 12 cases of atypical CPP and 81 cases of CPC. The median follow-up time was 3.5 years for CPP and 7.7 years for CPC. The median age at diagnosis was 4 years for CPP (10-90th percentile 0-16 years) and 1 year for CPC (10-90th percentile 0-10 years). In univariate regression analysis, CPC histology (ß = -3.2, 95% confidence interval, CI -4.8 to -1.5, p < 0.001) was significantly associated with younger age at diagnosis in comparison to CPP. The mean tumor size was 3.7 cm for CPP and 6.0 cm for CPC (p < 0.001). A higher-grade tumor was associated with significantly increased mortality (hazard ratio, HR = 28.90, 95% CI 3.94-211.83, p = 0.001). Overall survival at 5 years was 98.7% for CPP and 58.5% for CPC (p < 0.001). Among those patients with CPC, gross total resection (GTR) was associated with a significantly lower mortality (HR = 0.21, 95% CI 0.07-0.66, p = 0.007). Overall survival at 5 years was 70.9% after GTR, significantly better than 35.9% after subtotal resection (p = 0.012) and 30% after no surgery (p = 0.003). Radiation treatment was not found to confer a survival benefit in CPC. No demographic characteristics (age, sex, race, date of diagnosis) were significantly associated with mortality. CONCLUSIONS: Analysis of a pediatric cohort of choroid plexus tumors in children in the SEER database shows that tumor grade is predictive of survival. In cases of CPC, the extent of surgical resection, especially GTR, is significantly associated with increased survival. Radiation did not confer survival benefit.

Primary tumors of the lateral ventricles of the brain.

BACKGROUND: The lateral ventricles are located in the center of the brain. Each ventricle lies in contact with five critical neural structures: the caudate nucleus, the thalamus, the fornix, the corpus callosum, and the genu of internal capsule.The authors report their experience in primary tumors of the lateral ventricles of the brain by analysing the symptomatology,the surgical treatment, the complications and the postoperative results. OBJECTIVE: To determine the importance of the surgical technique on the morbidity and the recurrence of lateral ventricles tumors. Total surgical resection followed by radiotherapy and or chemotherapy had been the main objective in the cases of anaplastic tumors. METHODS: This retrospective study makes reference to 202 primary tumors of the lateral ventricles operated by Leon Danaila between 1982 and 2012. The respective analysis is based on the operative approaches and on the extent of resection. The surgical access routes were the interhemispheric transcallosal approach and the transcortical approach. RESULTS: A number of 177 (87%) of the primary tumors of the lateral ventricles were benign (low grade lesions), while 25(12.37%) of them were anaplastic. The most frequent tumors were ependymomas, astrocytomas, subependymomas, choroid plexus papillomas and meningiomas. Out of the total of 202 tumor cases, 164 (81.18%) were discharged with very good and good results, 35 (17.32%) were left with neurological deficits,and 3 (1.48%) died. A significant proportion of the patients undergoing surgery develop cerebrospinal fluid outflow obstruction, and this fact made the postoperative mounting of a number of ventricular shunts necessary. CONCLUSION: The majority of these tumors were benign, with are latively slow growth rate. Owing to this fact, the preoperative dimensions of the tumors were of several centimeters. The average age of the patients was lower than that of those with similar lesions located intraparenchymatously. The symptoms were determined by the ventricular outflow obstruction and by the affectation of the periventricular structures. Interhemispheric transcallosal and transcortical approaches were the best surgical access routes.

Choroid plexus tumors in children less than 36 months: the Canadian Pediatric Brain Tumor Consortium (CPBTC) experience.

BACKGROUND: Choroid plexus tumors (CPT) are rare pediatric tumors. A population-based study on choroid plexus carcinoma (CPC) and choroid plexus papilloma (CPP) was carried out to describe the incidence, demographic, and outcome data and to identify potential prognostic factors. METHODS: The CPT population from the Canadian databank of CNS tumor in children ≤ 36 months diagnosed between 1990 and 2005 was reviewed RESULTS: Out of the 579 reported cases of CNS tumors, 37 were CPT. The annual age-adjusted incidence rate was 0.22 + 0.12 (95% CI 0.16-0.28)/100,000 children < 3 years. There were 21 (56.7%) CPP and 16 (43.3.5%) CPC. Twenty patients (54%) were males. Median age at diagnosis was 7 months(range 0-30). Ten patients(62.5%) with CPC and one with CPP were metastatic at diagnosis. Twenty patients with CPP (95%) had a complete resection, whereas 6/16 CPC (37.5%) achieved a resection >90%. Fourteen CPC patients received adjuvant chemotherapy. None of the 37 patients received adjuvant radiation. At completion of survey, all CPP and five CPC were alive. Median survival time for CPC patients was 15 months (0-120). One death was related to intraoperative hemorrhage, another to chemotherapy-induced toxicity, and one to secondary AML. Age at diagnosis, degree of resection and metastatic status were not significant prognostic factors for CPC. CONCLUSION: By contrast to CPC, CPP have an excellent prognosis following surgery alone. Survival of CPC remains poor. However, these data may suggest adjuvant chemotherapy can alter the aggressive natural history of CPC. As with other rare CNS tumors, international collaboration is required to identify optimal therapy.

Molecular insights into malignant progression of atypical choroid plexus papilloma.

Choroid plexus tumors are rare pediatric neoplasms ranging from low-grade papillomas to overtly malignant carcinomas. They are commonly associated with Li-Fraumeni syndrome and germline TP53 mutations. Choroid plexus carcinomas associated with Li-Fraumeni syndrome are less responsive to chemotherapy, and there is a need to avoid radiation therapy leading to poorer outcomes and survival. Malignant progression from choroid plexus papillomas to carcinomas is exceedingly rare with only a handful of cases reported, and the molecular mechanisms of this progression remain elusive. We report a case of malignant transformation of choroid plexus papilloma to carcinoma in a 7-yr-old male with a germline TP53 mutation in which we present an analysis of molecular changes that might have led to the progression based on the next-generation genetic sequencing of both the original choroid plexus papilloma and the subsequent choroid plexus carcinoma. Chromosomal aneuploidy was significant in both lesions with mostly gains present in the papilloma and additional significant losses in the carcinoma. The chromosomal loss that occurred, in particular loss of Chromosome 13, resulted in the losses of two critical tumor suppressor genes, RB1 and BRCA2, which might play a possible role in the observed malignant transformation.

Prenatal diagnosis and successful postnatal therapy of an atypical choroid plexus papilloma-Case report and review of literature.

This report describes the perinatal management of a prenatally detected choroid plexus papilloma in an otherwise unaltered singleton pregnancy of a healthy woman. After elective Caesarean section, a successful embolization of the feeding vessel followed by a craniotomy and complete removal of the remaining tumor were performed. Histological examination confirmed the diagnosis. One-, 2-, and 3-year follow-up showed a normal development of the girl with a regular neuropediatric status. A review of literature including related papers listed in PubMed between 1985 and 2009 are included.

Variations of disseminated choroid plexus papilloma: 2 case reports and a review of the literature.

BACKGROUND: Choroid plexus papillomas are typically considered benign lesions, but histology is not always predictive of their behavior. These tumors can metastasize anywhere along the neuraxis and may be intraventricular, subarachnoid, or intraparenchymal. We present 2 cases that illustrate the wide diversity with which choroid plexus papillomas can disseminate. CASE DESCRIPTIONS: The patient described in case 1 had a primary fourth ventricular choroid plexus papilloma that produced diffuse cystic subarachnoid and leptomeningeal lesions. Patient 2 also had a primary fourth ventricular tumor but with subsequent suprasellar and spinal drop metastases. Patient 1 was treated with temozolomide, resulting in regression of symptoms including headache and dizziness. Patient 2 has been treated with several modalities, including radiation therapy and chemotherapy, with slowing of symptom progression. CONCLUSIONS: Variations of choroid plexus papilloma dissemination include intraventricular, subarachnoid, and leptomeningeal nodules or cystic lesions, and intraparenchymal locations. There is no consensus on the most effective treatment for choroid plexus papilloma metastases; surgical resection, chemotherapy, and radiation therapy may all yield benefits. The prognosis for patients with disseminated choroid plexus papilloma can range from prolonged stable disease and symptoms to death within months.

Pediatric choroid plexus neoplasms.

PURPOSE: Choroid plexus tumors (CPT) are rare childhood neoplasms. The relatively small number of reported cases and the controversies surrounding the clinical and pathological classification of these tumors have made it difficult to define a standard of care for these patients. Our intention is to contribute to the body of knowledge of these tumors and further define the role of adjuvant therapy. METHODS AND MATERIALS: We performed a retrospective review of 14 children with choroid plexus neoplasms referred to St. Jude Children's Research Hospital between October 1985 and December 1987. Ten patients had choroid plexus carcinoma (CPC) based on pathologic criteria and evidence of brain invasion at surgery or leptomeningeal disease (M+); 4 patients had choroid plexus papilloma (CPP). Patients with CPP were initially treated with surgery alone whereas patients with CPC were generally treated with postoperative therapy that included chemotherapy (CT) and/or craniospinal irradiation (CSI) with a focal boost to the primary site. For most patients CT consisted of combinations of cyclophosphamide, etoposide, vincristine, and a platinum agent. The median CSI dose was 35.2 Gy (range 24-46.2 Gy). The median primary site dose was 55.2 Gy (range 49.6-64 Gy). RESULTS: Seven of the 10 CPC cases presented with leptomeningeal dissemination; two of these patients have succumbed to disease. Of the 3 patients with M0 status, all are alive with no evidence of disease (NED). The medial time to relapse from the time of surgery was 5.3 mo (range 3-25 mo). Seven CPC patients were treated with gross total resection (GTR). Three of these patients (2 M0, 1 M+) received CT without CSI and are currently NED (27, 69, and 60 mo respectively). One M+ patient progressed on CT and has stable disease after CSI (6 mo), one (M0) received CT and CSI and is NED (120 mo), one (M+) is currently on CT with objective response (3 mo) and one (M+) died of progressive disease (24.5 mo) despite CT and CSI. Three patients with CPC had subtotal resection (STR). One of these patients (M+) received CT and CSI and is NED (23 mo), one (M0) had an elective second resection GTR alone and is currently NED (153 mo), and one (M+) developed progressive disease (13.5 mo) while on CT and died despite CSI. Among the 4 CPP patients, GTR was performed in two; both were NED at 54 and 81 mo. Two patients with CPP (one with focal atypia) were treated with STR initially; both transformed to CPC at 7 and 27 mo, respectively. Both were currently NED following salvage with (1) GTR and CSI alone (98 mo) or (2) STR, CT, and CSI (62 mo). Six of the 12 survivors in this series had significant neuropsychological sequelae. CONCLUSION: The prognosis of CPP is good for patients treated with GTR. Malignant transformation occurred in 2 CPP patients with less than GTR. Patients with localized CPC who undergo GTR have had a favorable outcome with the addition of chemotherapy or irradiation. CSI may not be routinely indicated in M0 children following GTR. There is evidence that salvage with radiation therapy may be successful following progression on chemotherapy. For patients treated with STR, the use of CT and CSI appears to be necessary.

Segmental myoclonus as the sole manifestation of a choroid plexus papilloma in the posterior fossa. Case report.

The authors describe the case of a 22-year-old woman with involuntary contractions of the sternocleidomastoid and trapezius muscles that resulted in turning movements of the head. The jerks displayed the clinical and neurophysiological characteristics of segmental myoclonus (SM) restricted to muscles supplied bilaterally by the first four cervical segments. Magnetic resonance imaging disclosed a tumor in the midline above the cisterna magna that was later histologically proven to be a choroid plexus papilloma. The patient's involuntary movements did not extend to other muscle groups or, in particular, to the palate, as one might have expected in the case of brainstem lesions. Myoclonus was the sole clinical manifestation of the tumor in this patient; other signs and symptoms invariably reported in other cases of posterior fossa papilloma, such as increased intracranial pressure or cranial nerve palsies, were absent. Release from suprasegmental control is suggested as a possible pathophysiological mechanism in this case of SM.

Choroid plexus tumors: a review of 28-year experience.

The aims of the study were to review the patients with choroid plexus tumor (CPT) treated in Slovenia between 1972-1999, to calculate the incidence of CPTs, and to evaluate treatment results in respect to tumor histology and mode of therapy. Cancer Registry of Slovenia database was used for patients identification. Histological specimens and medical records were reviewed. Twelve patients (7 females, 5 males), 0.8-43 years old (median 6.1 years; <15 years: 10/12,83%) with CPT, representing 0.36% of all intracranial tumors registered during the period under study, were identified. Considering children less than 15 years old only, the corresponding percentage was 3.69. There were eight papillomas (CPPs) and four carcinomas (CPCs) with no difference in age distribution between the groups. Of seven patients with gross tumor resection in CPP group, one patient died of postoperative meningitis and one had local recurrence 1.6 years after surgery; the latter is disease-free 17.9 years after re-operation. One patient with macroscopic residue after surgery is alive and asymptomatic after 16.5 years. In the CPC-group, only the patient who received adjuvant BEP chemotherapy and craniospinal irradiation following incomplete surgery is alive with no signs of disease after 6.5 years. Ten-year disease-specific survival for all CPTs and for CPP subgroup was 73% and 100%, respectively. In Slovenia, CPTs represent 0.36% of intracranial tumors. In children, the incidence is 3.69%. CPPs are twice as frequent as CPCs. In CPPs, the treatment of choice is surgery alone. After incomplete surgery, wait-and-see policy seems to be justified. For CPCs, adjuvant multiagent chemotherapy and craniospinal radiotherapy following surgery should be considered.

Choroid plexus papillomas: advances in molecular biology and understanding of tumorigenesis.

Choroid plexus papillomas are rare, benign tumors originating from the choroid plexus. Although generally found within the ventricular system, they can arise ectopically in the brain parenchyma or disseminate throughout the neuraxis. We sought to review recent advances in our understanding of the molecular biology and oncogenic pathways associated with this disease. A comprehensive PubMed literature review was conducted to identify manuscripts discussing the clinical, molecular, and genetic features of choroid plexus papillomas. Articles concerning diagnosis, treatment, and long-term patient outcomes were also reviewed. The introduction of atypical choroid plexus papilloma as a distinct entity has increased the need for accurate histopathologic diagnosis. Advances in immunohistochemical staining have improved our ability to differentiate choroid plexus papillomas from other intracranial tumors or metastatic lesions using combinations of key markers and mitotic indices. Recent findings have implicated Notch3 signaling, the transcription factor TWIST1, platelet-derived growth factor receptor, and the tumor necrosis factor-related apoptosis-inducing ligand pathway in choroid plexus papilloma tumorigenesis. A combination of commonly occurring chromosomal duplications and deletions has also been identified. Surgical resection remains the standard of care, although chemotherapy and radiotherapy may be considered for recurrent or metastatic lesions. While generally considered benign, these tumors possess a complex biology that sheds insight into other choroid plexus tumors, particularly malignant choroid plexus carcinomas. Improving our understanding of the molecular biology, genetics, and oncogenic pathways associated with this tumor will allow for the development of targeted therapies and improved outcomes for patients with this disease.

Atypical transformation in sacral drop metastasis from posterior fossa choroid plexus papilloma.

Choroid plexus papillomas (CPP) are rare tumours and spinal metastases of CPP are even less common. We report a 50-year-old woman with spinal drop metastases at Th9 and S1-2 6 years after total resection of a posterior fossa CPP. The metastasis at S1-2 was resected and histological examination showed transformation to an atypical CPP. Atypical transformation in a metastasis years after resection of a benign posterior fossa CPP has been described once. We would like to advocate craniospinal MRI at the time of initial diagnosis as well as periodic follow-up after total and subtotal resection of a posterior fossa CPP in adults at least once in 1 or 2 years, depending on the histological grading of the primary CPP. In our case report, this could have resulted in earlier diagnosis of the locoregional recurrence or of the spinal drop metastasis.

Malignant transformation in mature cystic teratoma of the ovary: three cases mimicking primary ovarian epithelial tumors.

This study reports 3 unusual cases of malignant transformation in mature cystic teratoma of the ovary (dermoid cyst), namely carcinosarcoma, atypical choroid plexus papilloma, and papillary thyroid carcinoma, the last case involving both ovaries and with peritoneal dissemination. Adequate sampling is essential in such ovarian tumors to establish their teratomatous origin and avoid an erroneous diagnosis of primary ovarian or metastatic tumors. The authors present the clinicopathological findings in these 3 cases with a review of literature.