The use of immunomorphology to differentiate choroid plexus tumors from metastatic carcinomas

Primary adult choroid plexus carcinomas: a single-center experience with a systematic review

Objective

Primary adult choroid plexus carcinomas (PACPCs) are extremely rare brain tumors. The existing literature primarily comprises case reports, which limits our understanding of this uncommon disease. This study aims to describe the clinical characteristics and prognosis of PACPCs, as well as to identify optimal treatment strategies.

Methods

We conducted a comprehensive analysis of clinical data from 7 patients with PACPCs who underwent surgical treatment at the Department of Neurosurgery, Beijing Tiantan Hospital, between March 2011 and March 2023. Additionally, a thorough search of the PubMed database was performed using the keywords "choroid plexus carcinoma" or "choroid plexus carcinomas" within the time frame of August 1975 to April 2023, which yielded a total of 28 identified cases. Subsequently, we evaluated risk factors for progression-free survival (PFS) and overall survival (OS) based on the pooled cases.

Results

The pooled cohort, consisting of 7 cases from our institution and 28 cases from the literature, included 20 males and 15 females with a mean age of 44.3 ± 14.7 years (range: 21-73 years). Gross-total resection (GTR) and non-GTR were achieved in 22 (62.9%) and 13 (37.1%) patients, respectively. Radiotherapy and chemotherapy were administered to 29 (90.6%) and 13 (40.6%) patients, respectively. After a mean follow-up of 21.0 ± 26.7 months (range: 2-132 months), 18 patients were alive, and 11 patients had died. The multivariate Cox regression model demonstrated that non-GTR (HR 5.262, 95% CI 1.350-20.516, p=0.017) was a negative prognostic factor for OS. However, we did not find any risk factors for PFS.

Conclusion

Complete surgical resection should be considered as the primary treatment approach for this rare disease. Chemotherapy and radiotherapy appear to have limited effectiveness in treating this condition. Further research with large cohorts is needed to validate our conclusions.

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.

A case of choroid plexus papilloma with stromal sclerosis and indistinct papillary structures

We present a case of choroid plexus papilloma with unusual histopathological findings. A 41-year-old Japanese man presented with dizziness. Brain magnetic resonance imaging scan showed a distinct mass in the fourth ventricle. Histopathological examination showed proliferation of cuboidal cells forming irregular trabeculae, small nests, and pseudoglandular and indistinct papillary structures, accompanied by a variable degree of stromal sclerosis. The tissue sections also showed rare mitotic activity, no hypercellularity, cellular pleomorphism, or necrosis. The immunohistochemical findings were tumor cells positive for cytokeratin 7, vimentin, S-100 protein, and transthyretin but negative for cytokeratin 20, BerEP4 and carcinoembryonic antigen. These findings were consistent with choroid plexus papilloma. The combination of these immunohistochemical markers was helpful in establishing the diagnosis, although the morphological finding of stromal sclerosis is rare for choroid plexus papilloma.

Increased incidence of choroid plexus carcinoma due to the germline TP53 R337H mutation in southern Brazil

Background

Choroid plexus carcinomas (CPC) are rare tumors predominantly found in children. Given the high frequency of the germline R337H mutation in the TP53 gene in southern Brazil, we have evaluated the frequency of the R337H mutation in families with CPC in children.

Methodology/Principal Findings

The present series included 29 patients that were admitted to the same institution from 1992 to 2010, including 22 children with CPC (0.08–13.6 years of age at diagnosis) and 7 children with papilloma of the choroid plexus (Pp; 0.5–9.8 years of age). Surgical resection was possible in 28 children. Blood and/or tumor DNA was extracted and analyzed using PCR-RFLP and results were confirmed by sequencing 240 bp of the TP53 exon 10. The patients, all parents, and some relatives submitted samples for blood DNA analysis. In addition, we have also examined the presence of the mutation in DNA from paraffin-embedded tumor samples to evaluate loss of heterozygosity. We found 63.3% (14/22) of the CPC patients positive for the germline R337H mutation; CPC samples were either heterozygous (n = 7), lost only the wild-type (n = 4), or only the R337H copy (n = 2). One CPC sample was not available. All Pp cases (7/7, 100%) were negative for R337H. Cure (>5 years survival free of disease) was observed in 18.1% of the CPC cases with the R337H mutation (2/11), 71.4% of the Pp (5/7), and 25% of CPC cases negative for the R337H mutation (2/8). Family history of cancer (with 2 or more cancer cases) was exclusively identified on the parental side segregating the R337H mutation, and 50% (7/14) of them were compatible with Li-Fraumeni-like syndrome.

Significance

Our results show for the first time that the R337H TP53 mutation is responsible for 63% of the CPC cases in children, suggesting a higher incidence of CPC in southern Brazil.

Choroid plexus carcinoma secreting carbohydrate antigen 19-9 in an adult. Case report

A 53-year-old man presented with a choroid plexus carcinoma in the body of the right lateral ventricle manifesting as gait disturbance due to left mild hemiparesis and papilledema. Subtotal removal of the tumor was performed. Histological examination revealed well-differentiated papillary adenocarcinoma. Immunohistochemical examination showed intense reactivity for carbohydrate antigen 19-9 (CA19-9). The serum level of CA19-9 was significantly high, but decreased rapidly after radiation therapy. Systemic examinations found no malignancy in other organs. This second case of choroid plexus carcinoma producing CA19-9 indicates that CA19-9 may be a useful marker of choroid plexus carcinoma.

Choroid plexus tumors differ from metastatic carcinomas by expression of the excitatory amino acid transporter-1

Tumors of the choroid plexus (CPTs) are rare neoplasms of neuroectodermal origin usually arising in pediatric patients. However, CPT may occur at any age, and their distinction from metastatic carcinomas is often difficult in adult cases. Because CPTs frequently show focal glial differentiation, we now investigated 35 CPTs (19 males and 16 females 0.3-70 years old; median age, 25.0 years), including 21 choroid plexus papillomas (CPPs), 5 atypical CPP, and 9 choroid plexus carcinomas regarding their expression of the excitatory amino acid transporter-1 (EAAT1, corresponding to rodent GLAST/GLAST-1) by immunohistochemistry. In addition, 77 metastatic carcinomas, including 64 adenocarcinomas with mostly papillary formations, derived from different organs were examined. Of the 35 CPTs, 23 (66%) showed membranous EAAT1 expression in variable numbers of tumor cells, including all atypical CPP and 3 of 9 choroid plexus carcinomas (33%). None of the metastatic carcinomas showed membranous immunostaining. Excitatory amino acid transporter-1 expression in CPT was significantly age dependent (P < .0001), with the proportion of EAAT1-positive tumor cells increasing with age, but not sex dependent. There was a highly significant difference between EAAT1 expression in CPT and in metastatic carcinomas (P < .0001). Establishing a cutoff value of 1% immunoreactive tumor cells served in adult cases to distinguish CPT from metastatic adenocarcinomas with 100% specificity and 70% sensitivity and was associated with positive and negative predictive values of 100% and 91%, respectively. Our findings indicate that EAAT1 immunohistochemistry may be useful in differentiating CPT from metastatic carcinomas.

[Choroid plexus tumours: epidemiologic comparative study of 24 cases]

Tumours derived from choroid plexus are rare central nervous system neoplasms affecting mainly children. This study presents a series of 38 patients with neuroectodermal tumours. Twenty four of them had the histological and/or immunohistochemical diagnosis of choroid plexus carcinoma (CPC). Sixteen of these patients were male. The left lateral ventricle was affected in most cases. Main clinical features were: hydrocephalus, intracranial hypertension and convulsion. All the patients were treated by surgery. There were 2 deaths due to surgical complications. Nine patients had recurrence, dying in a intermediate time of 12.3 months and 7 patients remain alive. The other cases did not present available data. CPC is very prevalent in Curitiba when compared to other choroid plexus tumours and it might be related to some pathogenic agent.

Keratin expression in human tissues and neoplasms

Keratin expression in human tissues and neoplasms Keratin filaments constitute type I and type II intermediate filaments (IFs), with at least 20 subtypes named keratin 1-20. Since certain keratin subtypes are only expressed in some normal human tissues but not others, and vice versa, various tissues have been subclassified according to the pattern of keratin staining. Simple epithelia generally express the simple epithelial keratins 7, 18, 19, and 20, while complex epithelia express complex epithelial keratins 5/6, 10, 14, and 15. When an epithelium undergoes malignant transformation, its keratin profile usually remains constant. The constitution and expression patterns of keratin filaments in human epithelial neoplasms are complex and often distinctive. In this article, we first briefly review the molecular and cell biology of keratin filaments. We then focus on the expression patterns of keratin filaments in various human neoplasms.

Schneiderian papillomas and nonsalivary glandular neoplasms of the head and neck

Schneiderian papillomas and nonsalivary glandular neoplasms of the head and neck continue to be a source of confusion for both the clinician and pathologist. An update on these lesions is provided.

Pathological and immunohistochemical studies of choroid plexus carcinoma of the dog

Choroid plexus carcinomas in four dogs (three male, one female) aged small middle 2.5 to 10 years, were examined by light microscopy and immunohistochemistry. The dogs showed progressive neurological signs including ataxia, seizures, vestibular disease and cranial nerve deficits, lasting for several months in some cases. Primary tumours were localized in the lateral (one case), third (one case), and fourth (two cases) ventricles. Hydrocephalus was evident at post-mortem examination in one case. In two cases the neoplastic cells closely resembled the structure of normal choroid plexus, with a distinct papillary pattern, composed of well-differentiated columnar epithelium. In the other two cases, cellular pleomorphism, nuclear atypia, increased mitotic activity and necrosis were observed. In all cases, dissemination of neoplastic cell clusters was detected within the subarachnoid space or the ventricular cavity. Immunohistochemical examination showed a multifocal labelling pattern for pankeratin and cytokeratin AE1 and diffuse vimentin positivity in poorly differentiated tumours. Well-differentiated choroid plexus carcinomas showed multifocal immunoreactivity for cytokeratin AE3, multifocal to diffuse immunoreactivity for vimentin and occasional positivity for carcinoembryonic antigen. Epithelial membrane antigen, Ber EP4 and S-100 were negative in all cases. Glial fibrillary acidic protein labelling occurred only in a single, poorly differentiated tumour. Occasional reactions for proliferating cell nuclear antigen and MIB-1 were seen in two cases. It was concluded that at least two morphological and possibly phenotypic subtypes (well-differentiated and anaplastic) of choroid plexus carcinoma of the dog could be identified.

Choroid plexus carcinoma in an adult

Choroid plexus carcinomas are rare in adults. They can behave aggressively and their optimal management is uncertain. An adult patient with choroid plexus carcinoma who was treated with an incomplete surgical resection and postoperative radiotherapy is reported. Despite an identifiable local response to radiotherapy, disease progression resulted in death 4 years after presentation. This report reviews the current literature and discusses the management issues regarding this uncommon adult malignancy.

Tumors of the choroid plexus

Choroid plexus tumors are rare intraventricular papillary neoplasms derived from choroid plexus epithelium, which account for only between 0.4-0.6% of all intracranial and 2-3% of pediatric neoplasms. Plexus papillomas outnumber choroid plexus carcinomas by a ratio of 5:1 and around 80% of choroid plexus carcinomas arise in children. Plexus tumors are most common in the lateral and fourth ventricles; while 80% of lateral ventricle tumors present in children, fourth ventricle tumors are evenly distributed in all age groups. Clinically, choroid plexus tumors tend to cause hydrocephalus and increased intracranial pressure. Histologically, choroid plexus papillomas correspond to WHO grade I, choroid plexus carcinomas to WHO grade III. Immunohistochemically, cytokeratins and vimentin are expressed by virtually all choroid plexus papillomas and most choroid plexus carcinomas while transthyretin and S-100 protein are present in 80-90% of cases, less frequently, though, in choroid plexus carcinomas. Glial fibrillary acidic protein can be found focally in about 25-55% of choroid plexus papillomas and 20% of choroid plexus carcinomas. The mean Ki67/MIB1 labeling index for choroid plexus papillomas is 1.9%, for choroid plexus carcinomas 13. 8%. Choroid plexus papillomas typically show hyperdiploidy with gains particularly on chromosomes 7, 9, 12, 15, 17, and 18 while one choroid plexus carcinoma showed rearrangements of chromosomes 7p11-12, 9q11-12, 15q22, and 19q13.4. Choroid plexus papillomas can usually be cured by surgery alone with a 5-year survival rate of up to 100% with occasional recurrences while choroid plexus carcinomas grow more rapidly and have a less favorable outcome with a 5-year survival rate of 26-40%.

Cytokeratin 7 and 20 expression in choroid plexus tumors: utility in differentiating these neoplasms from metastatic carcinomas

Tumors derived from choroid plexus epithelium are uncommon and may exhibit a wide variety of histologic patterns. They often are difficult to distinguish from metastatic carcinomas. Previous studies that addressed this issue yielded conflicting results. Recent reports have demonstrated that evaluation of coordinate expression of cytokeratin (CK) 7 and CK20 aids in distinguishing primary from metastatic lesions in a number of anatomic sites and that tumors that commonly are metastatic to the brain retain their CK7/CK20 immunophenotype in this location. We examined 35 choroid plexus tumors with a panel of antibodies to determine their CK7/CK20 immunophenotype. Tumors from 35 patients (7 male, 28 female; mean age, 25 years), including 31 choroid plexus papillomas and 4 atypical papillomas, were evaluated. All tumors were intraventricular or within the cerebellopontine angle and composed predominantly of orderly columnar epithelial cells resting on distinct fibrovascular cores. Atypical papillomas contained combinations of focal loss of architectural pattern, increased mitotic activity, necrosis, and brain parenchymal invasion. No lesion was unequivocally malignant. Twenty-six tumors (74%), including all atypical papillomas, were CK7 positive and CK20 negative. Two tumors stained with both markers, one stained with CK20 only, and six stained with neither marker. Other findings included expression of glial fibrillary acidic protein in 24 tumors, S-100 protein in 19 tumors, transthyretin in 31 tumors, Ber EP4 in 1 tumor, CAM5.2 in 33 tumors, epithelial membrane antigen in 4 tumors, and pancytokeratin in 27 tumors. Our results indicate that the majority of choroid plexus tumors have a CK7-positive/CK20-negative immunophenotype. This finding may be useful in differentiating these lesions from metastatic carcinomas that have differing CK7/CK20 profiles.

[Choroid plexus carcinoma: report of 15 cases]

Choroid plexus carcinoma (CPC) are rare central nervous system tumours derived from choroid plexus epithelium, affecting mainly children under 3 years of age. We present a clinical, epidemiological and histopathological study of 15 cases of CPC. Ten patients were male. Age ranged from 4 months to 21 years (mean=3,4). The lateral ventricles were affected in 73,3% of cases. Main symptom were: hydrocephalus (62.5%), intracranial hypertension (25%) and convulsion (12.5%). The patients were treated by surgery with partial resection in 75% of cases and total resection in 25%. There was one death due to surgical complication, 85.7% of patients had recurrence of tumours with mean survival rate of 13.6% months after diagnosis. Only one patient remain alive 5 years after initial treatment. These results support the poor prognosis and high mortality rate of CPC.

Pathology of choroid plexus papillomas: a review

Choroid plexus papillomas (CPPs) are rare, usually slow growing neoplasms. Their biological behaviour cannot be predicted in an individual case. Furthermore, the neuropathological diagnosis of these neoplasms is occasionally difficult because light and electron microscopical and immunohistochemical features may overlap with those of other neoplasms localising in the choroid plexus. The aim of this paper is to review the pathological literature (light and electron microscopy (EM) and immunocytochemistry), to provide guidance on current diagnostic tools and criteria and address the identification of 'atypical' CPPs, e.g. those CPPs with histological features indicative of aggressive behaviour, in an attempt to help bridge the diagnostic gap between benign CPPs on the one hand and choroid plexus carcinomas (CPCs) on the other.

Tubular adenoma of the choroid plexus: evidence for glandular differentiation of the neuroepithelium

A case of tubular adenoma arising in the right ventricular choroid plexus of a 4-month-old boy is described. A basic pattern of neoplastic glandular epithelium and lack of papillary architecture distinguished this tumor from a papilloma. Coexpression of S -100 protein, transthyretin and cytokeratin identified the neoplastic cells as being of choroid plexus origin. Immunohistochemical detection of MIB-1 showed a proliferation rate (16%) similar to adenomas in more conventional locations, but not encountered in benign brain tumors. In situ detection of DNA-derived oligonucleosomal fragments by TUNEL analysis, on the other hand, detected apoptotic activity in 5-8% of tumor cells. The indolent course of the disease in the present case, thus, might suggest a compensatory elimination of proliferating cells by apoptosis. This possibly points to mechanisms of neoplastic transformation different from those involved in choroid plexus papillomas.

Differential expression of cell adhesion molecules (CAM), neural CAM and epithelial cadherin in ependymomas and choroid plexus tumors

A series of frozen specimens of 18 ependymomas and 7 choroid plexus tumors were examined for their expression of cell adhesion molecules, such as neural cell adhesion molecule (NCAM), its polysialylated isoforms (PSA NCAM), and epithelial (E-) cadherin, and of intermediate filament proteins, such as glial fibrillary acidic protein (GFAP) and cytokeratin, using various monoclonal and polyclonal antibodies. Normal choroid plexus and ependyma were taken as controls. Anti-E-cadherin immunoreactivity was observed on the basolateral part of most adult choroid plexus and benign choroid plexus papilloma cells. However, a small number of atypical papillomas and carcinoma cells showed anti- E-cadherin immunoreactivity throughout their cell surface membrane. NCAM were not expressed by adult choroid plexus and benign papilloma cells. Only a few cells expressed NCAM and PSA NCAM in developing choroid plexus, atypical papillomas and carcinomas. Cytokeratin expression was always observed in choroid plexus and their tumors; GFAP expression was variable from case to case. In contrast, ependymal cells and their tumors never expressed E-cadherin but strongly expressed NCAM. PSA NCAM was found in ependymomas exhibiting anaplastic features. All ependymomas strongly expressed GFAP and a few demonstrated slight expression of cytokeratin. These data suggest that, besides GFAP and cytokeratin, NCAM and E-cadherin are of potential diagnostic value in distinguishing choroid plexus tumors from ependymomas. E-cadherin and NCAM may play a role in the functional organization of normal choroid plexus and ependyma, respectively. In particular, incomplete or irregular anti-E-cadherin expression in choroid plexus tumors and PSA NCAM immunoreativity in ependymomas and choroid plexus tumors correlates with the emergence of anaplastic histological features.