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.     

Immunohistochemical evidence of endothelin-1 in human choroid plexus

Summary An immunohistochemical investigation was carried out on 17 specimens of human choroid plexus obtained post mortem, 1 biopsy of normal choroid plexus including part of the lateral ventricle and 1 papilloma of the choroid plexus removed surgically. The material was fixed in formalin. Paraffin and cryostat sections were used. A polyclonal antiserum to endothelin-1 served as a primary antibody. The avidin-biotin-peroxidase method was applied to demonstrate the immunoreaction. The epithelial cells of the choroid plexuses, the choroid papilloma and most ependymal cells of the lateral ventricle showed a distinct brown reaction product in their cytoplasm indicating antigenic sites to endothelin-1. The reaction was of lesser intensity in the ependymal cells. The connective tissue in choroid plexus was unstained. A positive immunoreaction was present in the walls of some vessels in the choroid plexus in cryostat sections. This is the first report on the presence of antigenic sites to endothelin-1 in the epithelial cells of the human choroid plexus. The role of endothelin in these cells should be investigated to ascertain if the cells synthesize this biologically active peptide or if it is merely bound to receptors in them.Supported by grants from Swedish Medical Research Council, project 03020, 1987 Års stiftelse för strokeforskning, Selanders stiftelse, Åhlen-stiftelsen and Stiftelsen Gamla Tjänarinnor, Stockholm Sweden     

Clinicopathologic correlations in epithelial choroid plexus neoplasms: a study of 52 cases

Summary Sixty-seven tumor specimens of epithelial choroid plexus neoplasms obtained by 60 biopsies and 7 autopsies from 52 patients were investigated. Diagnoses of the first operations were choroid plexus papilloma (PP; 32 cases), choroid plexus papilloma with histological atypies (atypical PP; 6 cases), and choroid plexus carcinoma (PC; 14 cases). Carcinoembryonic antigen was expressed by 2 of the 3 biopsies autoptically recognized as metastatic carcinomas and by 2 autopsy cases of PC, while it was absent in all biopsies of true choroid plexus tumors. Tumor cells positive for transthyretin (TTR, prealbumin), S-100 protein (S100), and glial fibrillary acidic protein (GFAP) were detected in 39, 46 and 13, respectively, of the 49 cases of true choroid plexus tumors. Fourth ventricle tumors expressed more S100 (number of positive tumor cells) than lateral ventricle tumors, PP more S100 and TTR than atypical PP/PC. Tumors from patients 20 years of age and older expressed more GFAP and TTR than tumors from younger patients. Of the 30 patients with complete follow-up 19 were alive 2 to 11 years after surgery, including 7 recurrencies. Eleven died from the tumor 4 months to 7 years after surgery. The following histopathologic features (in order of decreasing significance) were correlated with poor prognosis (recurrency or fatal outcome): less than 50% of the tumor cells heavily positive for S100, presence of mitoses, absence of TTR-positive cells, brain invasion by cell nests, absence of marked stromal edema, and presence of necrotic areas. Our results indicate that some histologic features correlate significantly with poor prognosis and that immunohistochemical results correlate with tumor localization, age, and malignancy.     

Ultrastructure of disseminated choroid plexus papilloma

Summary A disseminated choroid plexus papilloma (DCPP) with a malignant change in the cervico-spinal leptomeninges observed 4 years after the removal of choroid plexus papilloma (CPP), originating from the fourth ventricle, was studied under the electron microscope. Although the ultrastructure of intracranial CPP has been reported by several authors, there are just a few reports on DCPP. The present tumor was ultrastructurally very similar to normal choroid plexus, but the lack of the capillary fenestration and of invaginations of the epithelial basal plasmalemmas suggested that the epithelium was deprived of secretory function.     

Comprehensive lectin histochemistry of normal and neoplastic human choroid plexus cells: alternation of lectin-binding patterns through neoplastic transformation

Summary Lectin histochemistry of the normal and neoplastic human choroid plexus cells [six choroid plexus papillomas (CPPs) and three choroid plexus carcinomas (CPCs)] was performed using eight representative lectins to study the development of sugar chain structures and also to determine whether lectins were useful for a histopathological diagnosis of choroid plexus neoplasms (CPNs). The normal choroid plexus cells reacted with Ricinus communis (RCA-I), Canavalia ensiformis (Con A), Limax flavus (LFA) and Triticum vulgaris (WGA), while Arachis hypoaea (PNA) stained them only after the removal of sialic acid. Human fetal choroid plexus cells at 8 weeks gestation already showed the same lectin-binding patterns as adult ones. All CPNs were stained by RCA-I and Con A in a similar manner as the normal choroid plexus cells. Although seven CPNs were positive for LFA, two CPCs were not stained by LFA, which bound to sialic acid. Two LFA-positive CPPs were stained by PNA before the removal of sialic acid. Moreover, unlike the normal choroid plexus cells, Ulex europaeus-, Glycine maximus- and Dolichos biflorus- binding sites often appeared, and WGA-binding sites of three CPNs remained even after sialic acid removal. In conclusion, the glycosialylation in normal choroid plexus cells was completed during the early embryonic stage. The lectin-binding patterns of CPNs were heterogenous in each case. The alternation of the glycosialylation and/or acquisition of binding sites for some lectins was sometimes observed through a neoplastic transformation.     

Choroidal bodies: a new structure in the fourth ventricular choroid plexus of the rat and mouse

Histologic study of the caudal end of the fourth ventricular choroid plexus of the rat and mouse revealed 1-4 small, discrete collections of cells that differed from the surrounding choroidal epithelial cells in appearance. They did not occur in other parts of the choroid plexuses. These choroidal bodies were not affected by a chemical toxin that caused hydropic degeneration of all the epithelial cells in the choroid plexuses. The function, if any, of the choroidal bodies is unknown. They were present in all rats that were studied by serial sections.     

First report of occurrence of choroid plexus papilloma and medulloblastoma in the same patient

Introduction Choroid plexus papilloma is a benign epithelial brain tumour showing a striking predilection for infants and occurring most frequently in the lateral and fourth ventricles. Medulloblastoma, on the other hand, is a primitive neuroectodermal tumour and is the most frequent malignant brain tumour of the posterior fossa in children. In this study, we report a metachronous occurrence of choroid plexus papilloma and medulloblastoma in the same patient, which has not been reported before to the best of our knowledge. Case report The authors describe the case of a girl who presented with an atypical choroid plexus papilloma on the posterior wall of the left lateral ventricle at 3 months of age that was resected completely. She was followed up regularly after surgery and made good progress with normal development. At 8 years of age, she presented with right cerebellar medulloblastoma. Discussion The authors review literature for incidence and aetiology of the two tumours.     

不典型脉络丛乳头状瘤1例：临床及病理研究

目的探讨不典型脉络丛乳头状瘤的临床特点、病理诊断及鉴别诊断。方法分析1例4岁男性不典型脉络丛乳头状瘤病人的临床资料，光镜下观察病理形态特征并行免疫组化研究。结果CT显示右侧颞叶脑实质占位。MRI显示右侧侧脑室囊实性占位。病理形态多样，部分区域分化差，细胞密度增加、核分裂3-5个／10HPF，呈片状方式生长。免疫组化结果：角蛋白（CK）、波形蛋白（Vimentin）阳性，上皮膜抗原（EMA）弱阳性；S-100、胶质纤维酸性蛋白（GFAP）等均为阴性。Ki-67阳性率局部〉5％。结论病人年龄、肿瘤准确定位等临床资料对病理诊断较为重要；严格掌握肿瘤的诊断标准并辅以合理的免疫组化检查，对诊断与鉴别诊断极为重要。     

Choroid plexus tumors in infancy and childhood. Focal ependymal differentiation

Summary Rubinstein and Brucher [18] tested 22 choroid plexus papillomas for the presence of glial fibrillary acidic protein (GFAP), using the immunoperoxidase technique and obtained focal positive results in nine cases, all of which were adults (19–66 years of age). They recommended performing a similar study in children with a view to determining the incidence of ependymal differentiation.Here we report an immunoperoxidase study of 32 cases (1 month to 14 years of age) of choroid plexus tumors in infancy and childhood tested for GFAP. Nineteen cases were classified as benign papillomas and 13 as malignant (four of which included benign areas). The most frequent site [15] was the lateral ventricle (22 cases). Next came the fourth ventricle (six cases), then the third ventricle (three cases), and lastly the pontocerebellar angle (one case). We found positive results focally in epithelial tumor cells in 11 of the 32 cases (34.3%). Nine were benign and two were maligant with areas of benign or differentiated papilloma. Positive cells were present in these areas. GFAP-positive cells were classified in two groups according to their location. Type 1 cells were located in the epithelium Some of them were small rounded in contact with the basement membrane, without reaching the surface; others were elongated and columnar, some extending into processes that reached the basement membrane or the vessel walls in the stroma of the papillae.Type 2 cells were observed in the stroma of the papillae; these were elongated and stained strongly.An interesting feature in five positive cases was the observation of nodes formed by Type 2 (stromal) cells and fibrils associated with Type 1 cells in the overlying epithelium. Our finding that glial differentiation in choroid plexus papilloma epithelial cells is as frequent in children as it had been reported to be in adults, does not support the idea of a greater capability of divergent differentiation in infancy and childhood.     

The role of endoscopic choroid plexus coagulation in the surgical management of bilateral choroid plexuses hyperplasia

Background Bilateral choroid plexus hyperplasia is a rare condition often associated with cerebrospinal fluid (CSF) overproduction. CSF overproduction is usually so high that the placement of a CSF ventriculoperitoneal shunt almost always results in progressive ascites leading to the necessity of removing the inserted shunt device. A direct surgical treatment of the hyperplastic choroid plexuses is then mandatory. Endoscopic coagulation of the choroid plexuses has been recently proposed as an alternative to open surgical plexectomy. However, the effectiveness of the procedure in controlling CSF overproduction is still debated.Technique We report a case of bilateral choroid plexus hyperplasia in which an extensive bilateral endoscopic coagulation of the choroid plexuses failed to reduce the CSF formation rate sufficiently. A one-stage bilateral open surgical plexectomy was performed.Results The procedure succeeded to control CSF overproduction. Intraoperative blood loss during the surgical removal of the choroid plexuses was significantly reduced due to the previous coagulation of their surface.Conclusion On these grounds, we suggest that endoscopic choroid plexuses coagulation, even when failing to normalize CSF production, may still be considered as a valid adjuvant procedure in the management of this condition.     

Expression of EAAT-1 distinguishes choroid plexus tumors from normal and reactive choroid plexus epithelium

Microscopic distinction of normal choroid plexus (CP) from choroid plexus tumors (CPT) may be difficult, especially in small samples of well-differentiated CP papillomas. So far, there are no established markers that reliably distinguish normal and neoplastic CP epithelium. Recently, a correlation between expression/function of glial glutamate transporters EAAT-1 (GLAST) and EAAT-2 (Glt-1) and tumor proliferation has been reported. Furthermore, we previously found that CPTs frequently express EAAT-1, but not EAAT-2. We now compared expression of EAAT-1, EAAT-2 and GFAP in non-neoplastic CP (n = 68) and CPT (n = 79) by immunohistochemistry. Tissue of normal CP was obtained from 50 autopsy cases (20 normal and 30 pathologic brains) and 18 neurosurgical specimens that included 17 fetal, 21 pediatric and 30 adult cases. In non-neoplastic postnatal CP (n = 51), focal expression of EAAT-1 was found in only two pediatric cases (4%). In CPT, expression of EAAT-1 was found in 64 of 79 (81%) tumor samples and was significantly age-dependent (P < 0.0001). Hence, EAAT-1 expression distinguishes neoplastic from normal CP, both in children (P = 0.0032) and in adults (P < 0.0001). Immunostaining for EAAT-2 in selected samples from cases of different ages showed that normal CP (n = 15) or CPT (n = 16) lacked EAAT-2 expression. GFAP expression was found in 3 of 32 (10%) normal CP and in 28 of 73 (38%) tumor samples. In conclusion, in contrast to neoplastic CP samples, expression of EAAT-1 is exceptionally rare in non-neoplastic CP. Thus, EAAT-1 is superior to GFAP as a helpful diagnostic tool in CP samples.     

Focal ependymal differentiation in choroid plexus papillomas

Summary Choroid plexus papillomas are usually easily distinguishable from papillary ependymomas by their delicate fibrovascular stroma and their cytologic similarity to normal choroid plexus epithelium. Exceptionally, however, examples are met which give rise to diagnostic difficulty. We therefore tested 22 choroid plexus papillomas for the presence of glial fibrillary acidic (GFA) protein using the immunoperoxidase technique. Positivity for the protein was found focally in epithelial tumor cells in nine of the 22 papillomas. All were in adults ranging from 19–66 years of age. Eight of the nine tumors originated in the 4th ventricle or from one of its lateral recesses. In six papillomas showing GFA protein in the cells, intracellular fibrils were found in a small number of elongated epithelial cells with the PTAH and/or Masson trichrome stains; in all these six cases, the GFA protein-positive cells were considerably more numerous than cells containing fibrils. Normal choroid plexus epithelium lacks GFA protein, but pathologically altered ependymal cells are often GFA protein-positive. Our findings therefore suggest that focal divergent glial (presumably ependymal) differentiation may be expressed in neoplastic choroid plexus epithelium, consistent with the origin of this epithelium from primitive neuroepithelial (ventricular) cells.This work was supported in part by Research Grant CA-11689 from the National Cancer Institute, USPHS     

Carbonic anhydrase activity during development of the choroid plexus in the human fetus

Carbonic anhydrase is one of the key enzymes responsible for the secretion of cerebrospinal fluid. This secretion increases dramatically during postnatal life in mammals. Nothing is known that can account for this regulation in the neonatal choroid plexus. However, the expression of carbonic anhydrase is developmentally regulated in several cells, such as erythrocytes and striated muscle fibers. The aim of our study was to assess the presence of carbonic anhydrase in epithelial cells of the choroid plexus during human development. We performed both histochemical and immunohistochemical detections of the enzyme on choroid plexuses between 9 and 34 weeks of gestation. We found that both carbonic anhydrase activity and the isozyme II were present as early as the 9th week of gestation. Expression of carbonic anhydrase is thus a very early event during plexus differentiation, and this enzymatic system could account for the secretion of cerebrospinal fluid during fetal life. Received: 14 February 1997     

Immunohistochemical study on distribution of transthyretin in normal human brain tissue and tumors

Immunohistochemical examination of transthyretin (TTR), which is known to be synthesized in the epithelial cells of the choroid plexus as well as in the liver cells, was carried out on normal brain tissues and 84 human brain tumors, using a peroxidase-antiperoxidase (PAP) technique. TTR was demonstrated diffusely and strongly in the cytoplasm of normal choroid plexus cells, but not in ependyma and other tissues of normal brain. In all of 10 choroid plexus papillomas, TTR was found within the cytoplasm of tumor cells. In contrast, neither the two papillary ependymomas nor any other brain tumors contained TTR. Among the choroid plexus papillomas, some cases showed clear positive reactions in almost all tumor cells, while others had only a few TTR-positive cells. With these immunohistochemical findings, TTR proved a very useful marker of normal choroid plexus and choroid plexus papilloma.     

Immunohistochemical study of insulin-like growth factor II (IGF-II) and insulin-like growth factor binding protein-2 (IGFBP-2) in choroid plexus papilloma

Abstract

Insulin-like growth factor-ll (IGF-II), a mitogen for various kinds of cells, has been shown to be secreted from the choroid plexus in animals. Insulin-like growth factor binding protein-2 (IGFBP-2), one of the six carrier proteins for IGFs, is also thought to be released from the choroid plexus, bind to IGF-II in the cerebrospinal fluid (CSF) and modulate the action of this growth factor. Little is known about the expression and localization of these substances in human choroid plexus and choroid plexus papillomas. The present immunohistochemical study demonstrated all six choroid plexus papillomas were positive for IGF-II, whereas normal choroid plexuses were negative for IGF-II. On the other hand, IGFBP-2 was positive in the endothelium and vascular media in the normal choroid plexus, while it was weakly positive in four and negative in two out of six choroid plexus papillomas. These results suggest that the alterations in the IGF-II/ IGFBP-2 axis might be involved in the tumorigenesis of choroid plexus papilloma. [Neurol Res 1999; 21: 339-344]     

Sellar-Suprasellar Extraventricular Choroid Plexus Papilloma : A Case Report and Review of the Literature

Choroid plexus papillomas (CPPs) are relatively rare neuroectodermal tumors that develop from choroid plexus epithelial cells and are usually restricted to the ventricles. Extraventricular CPPs are very unusual and can be difficult to diagnose and treat. A 50-year-old male patient was admitted to our clinic complaining of headache and visual deterioration. Neurological examination found no abnormalities except decreased light perception and secondary optic atrophy in the left eye. Endocrine testing revealed normal levels of hormones produced by the pituitary and target glands. Magnetic resonance imaging of the brain revealed a huge regular-shaped lesion in the sellar-suprasellar region occupying the sella turcica and extending into the suprasellar cistern and planum sphenoidale. The lesion was completely excised by microsurgery via an ordinary left-sided pterional approach. Histopathology identified the lesion as a choroid plexus papilloma. Following the case report, literature on the origin, differential diagnosis, and treatment of this rare tumor is reviewed.     

Oncocytic variant of choroid plexus papilloma

Summary Two cases of oncocytic plexus papilloma are presented which were in the fourth ventricle and cerebello-pontine angle in women aged 70 and 63 years, respectively. The cytoplasm of the transformed tumor cells was enlarged, eosinophilic, and granular; and it was characterized ultrastructurally by innumerable mitochondria. Most of them had lamellar cristae, a clear matrix, and contained dense granules. These oncocytes are identical with oncocytes of the human thyroid, parathyroid, bronchi, kidneys, adrenals, salivary gland and myocardium, and non-neoplastic choroid plexus epithelium. As far as we know, this is the first report of an oncocytic variant of the choroid plexus papilloma. Two unusual cases are described.     

An immunocytochemical comparison of the glia-associated proteins glial fibrillary acidic protein (GFAP) and S-100 protein (S100P) in human brain tumors

Immunostaining patterns of two glia-associated proteins, glial fibrillary acidic protein (GFAP) and S-100 protein (S100P), were compared using the peroxidase-antiperoxidase (PAP) method on adjacent paraffin sections in 100 brain tumors including 52 astroglial tumors, 13 oligodendrogliomas, 14 ependymomas, 13 choroid plexus papillomas and 8 medulloblastomas. Most astroglial tumors showed similar immunoreactivity for both proteins. Fibrillary processes, however, showed a stronger and more crisp staining with anti-GFAP than with anti-S100P, whereas cell nuclei were labeled only for S100P. Focal dissociation of immunoreactivities for the two proteins was prominent in several malignant astroglial tumors including giant cell glioblastoma, and in subependymal giant cell astrocytoma. In oligodendrogliomas, GFAP-positive neoplastic oligodendrocytes also showed immunoreactivity for S100P; a smaller number of tumor cells were immunoreactive only for S100P, comparable to normal mature oligodendroglia. Most ependymomas were characterized by a similar distribution of cells immunoreactive for both proteins. In choroid plexus papilloma, absent or only focal immunoreactivity for GFAP contrasted with diffuse labeling for S100P in all cases; this seems of value for a differential diagnosis of papillary CNS tumors. In medulloblastoma, some tumor cells of a classical type were immunoreactive only for S100P; on the contrary, GFAP positive tumor cells with sparse or absent immunoreactivity for S100P were found in desmoplastic medulloblastomas. Similar immunoreactivities for both proteins in most tumors suggest a generally parallel production of both proteins by glial tumor cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

A pigmented choroid plexus carcinoma: histochemical and ultrastructural studies.

A large tumor of the left lateral ventricle in a 3 1/2 year old male was diagnostic of malignant choroid plexus papilloma (choroid plexus carcinoma) as observed histologically. Focal neoplastic epithelial cells contained yellow-brown pigment which was not entirely compatible with melanin by histochemical techniques. Ultrastructurally, the tumor had definite evidence of choroid plexus origin. The neoplastic cells contained electron-dense and lamellar bodies, as well as structures of intermediate type. Premelanosomes were not observed. Thus there was no evidence for neural crest melanin. It is suggested that the pigment is probably lipofuscin and melanin derived from lipofuscin by "melanization" through pseudoperoxidation.     

Cell proliferation and differentiation from ependymal, subependymal and choroid plexus cells in response to stroke in rats.

We tested the hypothesis that populations of ependymal, subependymal and choroid plexus cells proliferate and differentiate after stroke in adult rats. Rats were subjected to 2 h of middle cerebral artery occlusion (n=70) and euthanized at 1, 2, 4, 7, 14, 21 and 28 days (10 per time point). Hematoxylin and eosin staining and immunostaining were performed using antibodies against bromodeoxyuridine, neuronal nuclear antigen and glial fibrillary acidic protein after stroke. In normal nonischemic rats (n=10), single layers of ependymal and choroid plexus cells do not react with bromodeoxyuridine, neuronal nuclear antigen or glial fibrillary acidic protein. Individual subependymal cells express glial fibrillary acidic protein and bromodeoxyuridine, but not neuronal nuclear antigen. After stroke, increased bromodeoxyuridine reactivity was present in multiple layers of ependymal cells and nodules of subependymal cells and in scattered choroid plexus cells from 2 to 28 days and peaked at 7 days. Bromodeoxyuridine immunoreactivity colocalized with neural phenotypes of neuronal nuclear antigen (approximately 0.1-3.5%) and glial fibrillary acidic protein (approximately 8.6%) immunoreactivity in cells in the ventricular zone and the subventricular zone, as well as in the choroid plexus of the ischemia affected hemisphere. Our data suggest that ependymal, subependymal and choroid plexus cells are potential neural precursor cells in the adult mammalian brain.