What Is a Choroid Plexus Tumor?

Choroid plexus tumors originate from choroid plexus epithelial cells in the ventricle of the brain. They occur in children and are the most common brain tumors at 1 year of age. There are mainly choroid plexus papilloma (English name: papilloma of choroid plexus, alias: choroid plexus papilloma) and choroid plexus cancer. Choroid plexus papilloma is a benign tumor that grows slowly and often causes cerebrospinal fluid flow disorders. It can be cured by surgery. Choroid plexus cancer is a malignant subtype of choroid plexus papillary tumors. Showing variability, often invading surrounding brain tissue. Common CSF transfer.

Choroid plexus tumor

Choroid Plexus Tumor

Choroid plexus tumor definition

Choroid plexus tumors are papillary tumors in the ventricle that originate from the choroid plexus epithelium.

Etiology of choroid plexus tumors

Simian virus (SV40) DNA sequence is a small primitive DNA virus (papillomavirus) that plays a role in the evolution of choroid plexus papilloma, choroid plexus cancer, and ependymal tumor. Forty years ago, the widespread use of attenuated SV40-containing acute polio vaccine caused recessive infections in millions of people. SV40 is a rodent oncogene, and choroid plexus papilloma has occurred in transgenic mice expressing the SV40 large T4 antigen. Choroid plexus papilloma and ependymal tumors have also been induced by inoculation of newborn rodents. However, follow-up studies in humans have shown that acute polio vaccine does not increase the incidence of cancer. Several early reports indicate that human brain tumors contain SV40-associated viral DNA. SV40-like virus has been isolated from human glioblastoma and cloned from human brain tumors. However, many reports suggest that isolation of SV40 cannot exclude the presence of SV40-bearing cell lines. Re-detection of SV40 suspected to be associated with human tumors by PCR showed that SV40-like DNA can be detected in 50% of human choroid plexus tumors and most ependymal tumors. Recent studies have detected credible sequences in different tumors, including tumors outside the central nervous system (mesothelioma, sarcoma) and normal tissues (such as semen, B, and T lymphocytes). Studies have found that these cells can be carriers Spread sV40 among the crowd. The presence of a virus in a tumor does not imply that it plays a role in tumorigenesis.

Clinical features of choroid plexus tumors

Choroid Plexus Tumor Symptoms and Signs

Choroid plexus tumors tend to block cerebrospinal fluid circulation, causing giant cranial signs (infant head circumference increase) and symptoms of increased intracranial pressure, such as vomiting, strabismus, and headache.

Choroid plexus tumor neuroimaging

On CT and MRI, high-density mass appears in the ventricle, which can be enhanced after enhancement, often accompanied by hydrocephalus.

Choroid plexus tumor classification

Choroid plexus papilloma

Choroid plexus papilloma is benign and consists of a layer of columnar epithelial cells surrounding a papillary structure of fine capillary fibrous tissue. The nucleus is round or oval and is located at the base of the epithelium. There are not many mitotic figures, no brain tissue invasion, and no necrosis. Choroid plexus papilloma is very similar to non-tumor choroid plexus, but the cells are crowded and slender. Occasionally, choroid plexus papilloma can exhibit rare histological features, including eosinophilic, mucinous, pigmented, and glandular tubular structures of tumor cells, as well as connective tissue changes such as yellow tumor-like changes, hemangio-like changes, and bone and cartilage formation. . Immunohistochemical staining Almost all choroid plexus papillomas express keratin and vimentin. S-100 protein is present in approximately 90% of cases. Epithelial membrane antigen was negative. GFAI is not expressed in normal choroid plexus epithelial cells, but 25% to 55% of choroid plexus papilloma is positive. Electron microscopy showed cell membranes with interdigitated fingers, tight junctions, microvilli, and occasionally basal membranes with apical cilia and basal surfaces of tumor cells.

Choroid plexus carcinoma

The tumor showed malignant features, including nuclear polymorphism, more common mitotic figures, significantly increased nuclear plasma ratio, increased nuclear density, inconspicuous papillary structure with focal necrosis of flaky tumor cells, and often diffusely infiltrated brain tissue. Immunohistochemical staining of choroid plexus carcinoma often expresses keratin, however, the positive rates of S-100 protein and thyroid transporter are lower than those of choroid plexus papilloma. About 20% of choroid plexus cancers are GFAP positive. Epithelial membrane antigens are often not expressed. In rare cases, choroid plexus cancer consists of atypical clear cells arranged into a solid structure, making diagnosis difficult. In these cases, electron microscopy is required to assist diagnosis.

Atypical choroid plexus papilloma

The difference between atypical choroid plexus papilloma and choroid plexus papilloma and choroid plexus cancer is not clear. Some tumors show only one or a few malignant histological features, such as increased mitotic figures. These tumors are called atypical choroid plexus papilloma, and clear diagnostic criteria have not been established.

Choroid plexus tumor differential diagnosis

Many tumors need to be distinguished from choroid plexus tumors. Villous hypertrophy is a diffuse enlargement of the choroid plexus of the two lateral ventricles, with normal histological morphology, and patients often have hypersecretory hydrocephalus. It is important to distinguish between choroid plexus cancer and metastatic cancer. Choroid plexus tumors co-express vimentin, keratin, and S-100 eggs, which helps distinguish them from other metastatic cancers. In addition} IEAl25 and Bm'EP4 also help because they mark 95% of brain metastatic cancers, while choroid plexus papilloma and choroid plexus cancer are only 10% positive. Thyroid transportin is involved in the conversion of thyroxine and vitamin A and is a marker of normal and neoplastic choroid plexus epithelium. But about 20% of choroid plexus papillomas are negative, while other brain tumors and metastatic cancers can be positive. Recently, synaptophysin was strongly positive in normal choroid plexus, choroid plexus papilloma, and choroid plexus carcinoma, but this finding has not been confirmed by others. One study showed that insulin-like growth factor II (IGFII) can be expressed in choroid plexus papilloma, but other brain tumors are negative. Since previous studies have shown that IGFll can be expressed in astrocytomas, meningiomas, and carcinomas, the differential diagnostic significance of IGF lJ remains to be confirmed. A positive carcinoembryonic antigen (CEA) indicates metastatic cancer, although occasionally choroid plexus cancer is also positive. Non-epithelial interlobular tumors can also originate from the choroid plexus, including meningiomas.

Choroid plexus tumor genetics

Choroid plexus papilloma and choroid plexus papilloma have appeared in I. in patients with i-Fraumeni syndrome. Four cases were reported, and three were germline mutations with TP53 codon 248. No mutations in TP53 were detected in sporadic choroid plexus papillary tumors. Cytogenetics and molecular genetics. Classical choroid plexus papilloma cells with genetic alterations and FISH showed hyperdiploidy, and 7, 9, 12, 15, 17, and 18 were obtained from chromosomes. Duplication of the short arm of chromosome 9 is associated with choroid plexus papilloma and choroid plexus hyperplasia. Superhaplotypes may be characteristic of choroid plexus papillary carcinoma.

Choroid plexus tumor classification

Choroid plexus papilloma is histologically equivalent to wHo class I, and choroid plexus carcinoma is equivalent to wHo m class.

Incidence of choroid plexus tumors

It accounts for 0.4% to 0.6% of all brain tumors, 2% to 4% of children's brain tumors, and 1% to 10% of children. The ratio of choroid plexus papilloma to choroid plexus cancer is 5: 1. About 80% of choroid plexus cancers occur in children, accounting for 20% to 40% of choroid plexus tumors. The annual incidence rate is 0.3 person / lO million.

Most patients with lateral ventricle tumors are younger than 20 years old. Tumors in the fourth ventricle can develop in all age groups. Ultrasound has been used to detect congenital and even embryonic tumors in the uterus. The incidence of lateral ventricle in men and women was 1: 1, and the fourth ventricle was 3: 2.

Choroid plexus tumor site

Choroid plexus papilloma and choroid plexus cancer occur in places with choroid plexus, that is, lateral ventricle (50%), third ventricle (5%), and fourth ventricle (40%). 2 or 3 ventricles are involved. 5 %. Tumors that occur in the cerebellopontine angle near the opening of the fourth ventricle are rare. Exceptional ectopic tumors can occur in soft tissue or on the saddle.