Primitive neuroectodermal tumor | |
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Other names | PNET |
Micrograph of an H&E stained section of a peripheral PNET. | |
Specialty | Oncology |
Primitive neuroectodermal tumor is a malignant (cancerous) neural crest tumor. [1] It is a rare tumor, usually occurring in children and young adults under 25 years of age. The overall 5 year survival rate is about 53%. [2]
It gets its name because the majority of the cells in the tumor are derived from neuroectoderm, but have not developed and differentiated in the way a normal neuron would, and so the cells appear "primitive". PNET belongs to the Ewing family of tumors.
Using gene transfer of SV40 large T-antigen in neuronal precursor cells of rats, a brain tumor model was established. The PNETs were histologically indistinguishable from the human counterparts and have been used to identify new genes involved in human brain tumor carcinogenesis. [3] The model was used to confirm p53 as one of the genes involved in human medulloblastomas, but since only about 10% of the human tumors showed mutations in that gene, the model can be used to identify the other binding partners of SV40 Large T- antigen, other than p53. [4] [ additional citation(s) needed ]
It is classified into two types, based on location in the body: peripheral PNET and CNS PNET.[ citation needed ]
The peripheral PNET (pPNET) is now thought to be virtually identical to Ewing sarcoma:
"Current evidence indicates that both Ewing's sarcoma and PNET have a similar neural phenotype and, because they share an identical chromosome translocation, they should be viewed as the same tumor, differing only in their degree of neural differentiation. Tumors that demonstrate neural differentiation by light microscopy, immunohistochemistry, or electron microscopy have been traditionally labeled PNETs, and those that are undifferentiated by these analyses have been diagnosed as Ewing's sarcoma." [5]
PNET of the CNS generally refer to supratentorial PNETs.
The approach to management of a CNS PNET is first to obtain detailed imaging through MRI, as well as additional scans of the patient's body (X-ray, CT, PET, even bone marrow biopsies) to look for metastasis or other associated malignancies. The tumor will then need to be biopsied to confirm the diagnosis. After the diagnosis of a CNS PNET is confirmed, management includes neoadjuvant chemotherapy and radiation (to reduce tumor size burden), complete surgical resection with confirmed negative margins, and/or additional adjuvant post-surgical chemotherapy. CNS PNET is aggressive and must be managed as so. Palliative care services should also become involved in the patient's care team when the diagnosis is made. [6]
A brain tumor occurs when abnormal cells form within the brain. There are two main types of tumors: malignant (cancerous) tumors and benign (non-cancerous) tumors. These can be further classified as primary tumors, which start within the brain, and secondary tumors, which most commonly have spread from tumors located outside the brain, known as brain metastasis tumors. All types of brain tumors may produce symptoms that vary depending on the size of the tumor and the part of the brain that is involved. Where symptoms exist, they may include headaches, seizures, problems with vision, vomiting and mental changes. Other symptoms may include difficulty walking, speaking, with sensations, or unconsciousness.
SV40 is an abbreviation for simian vacuolating virus 40 or simian virus 40, a polyomavirus that is found in both monkeys and humans. Like other polyomaviruses, SV40 is a DNA virus that sometimes causes tumors in animals, but most often persists as a latent infection. SV40 has been widely studied as a model eukaryotic virus, leading to many early discoveries in eukaryotic DNA replication and transcription.
Oligodendrogliomas are a type of glioma that are believed to originate from the oligodendrocytes of the brain or from a glial precursor cell. They occur primarily in adults but are also found in children.
This is a list of terms related to oncology. The original source for this list was the US National Cancer Institute's public domain Dictionary of Cancer Terms.
A blastoma is a type of cancer, more common in children, that is caused by malignancies in precursor cells, often called blasts. Examples are nephroblastoma, medulloblastoma, and retinoblastoma. The suffix -blastoma is used to imply a tumor of primitive, incompletely differentiated cells, e.g., chondroblastoma is composed of cells resembling the precursor of chondrocytes.
Medulloblastoma is a common type of primary brain cancer in children. It originates in the part of the brain that is towards the back and the bottom, on the floor of the skull, in the cerebellum, or posterior fossa.
Ewing sarcoma is a type of pediatric cancer that forms in bone or soft tissue. Symptoms may include swelling and pain at the site of the tumor, fever, and a bone fracture. The most common areas where it begins are the legs, pelvis, and chest wall. In about 25% of cases, the cancer has already spread to other parts of the body at the time of diagnosis. Complications may include a pleural effusion or paraplegia.
An atypical teratoid rhabdoid tumor (AT/RT) is a rare tumor usually diagnosed in childhood. Although usually a brain tumor, AT/RT can occur anywhere in the central nervous system (CNS), including the spinal cord. About 60% will be in the posterior cranial fossa. One review estimated 52% in the posterior fossa, 39% are supratentorial primitive neuroectodermal tumors (sPNET), 5% are in the pineal, 2% are spinal, and 2% are multifocal.
A pelvic tumor is any one of the numerous tumors that occur in the pelvis. Within the pelvis, these tumors may involve specific organs or tend to occupy intra-organ spaces. Tumors found in the presacral space and sacral space are most prevalent in children. Tumors occupying specific organs have a more complex natural history.
Malignant ectomesenchymoma(MEM) is a rare, fast-growing tumor of the nervous system or soft tissue that occurs in children and young adults. MEM is part of a group of small round blue cell tumors which includes neuroblastoma, rhabdomyosarcoma, non-Hodgkin's lymphoma, and the Ewing's family of tumors.
Ectomesenchymoma is a rare, fast-growing tumor of the nervous system or soft tissue that occurs mainly in children, although cases have been reported in patients up to age 60. Ectomesenchymomas may form in the head and neck, abdomen, perineum, scrotum, or limbs. Also called malignant ectomesenchymoma.
Gliosarcoma is a rare type of glioma, a cancer of the brain that comes from glial, or supportive, brain cells, as opposed to the neural brain cells. Gliosarcoma is a malignant cancer, and is defined as a glioblastoma consisting of gliomatous and sarcomatous components. Primary gliosarcoma (PGS) is classified as a grade IV tumor and a subtype of glioblastoma multiforme in the 2007 World Health Organization classification system (GBM). Because of a lack of specific and clear diagnostic criteria, the word "gliosarcoma" was frequently used to refer to glial tumours with mesenchymal properties, such as the ability to make collagen and reticulin.
The Ewing family of tumors (EFTs) is a group of small cell sarcomas including Ewing sarcoma of the bone, extra osseous Ewing tumors, and primitive neuroectodermal tumors. They are rare cancers, usually diagnosed in peoples' twenties. The sarcoma of bone is the most common of the variants. All forms are predisposed to metastasis and have had historically high rates of mortality. The family of tumors shares a common translocation mutation of the EWS gene on chromosome 22 to an ETS-type gene, most commonly the FLI1 gene. EFTs are highly malignant, with 5-year survival for patients with metastatic disease at 20%. The current standard of care includes resection, radiation, and chemotherapy.
Otmar D. Wiestler is a German physician, a professor at the University of Heidelberg and president of the Helmholtz Association. He is not a typical basic scientist, but he successfully entered a number of highly popular fields of clinical research, including cancer research, tumor genetics and, more recently, stem cell research. He focuses on technology transfer of already existing technologies from basic science into clinical use, rather than developing the basic science.
The WHOclassification of tumours of the central nervous system is a World Health Organization Blue Book that defines, describes and classifies tumours of the central nervous system (CNS).
Medulloepithelioma is a rare, primitive, fast-growing brain tumour thought to stem from cells of the embryonic medullary cavity. Tumours originating in the ciliary body of the eye are referred to as embryonal medulloepitheliomas, or diktyomas.
Pediatric ependymomas are similar in nature to the adult form of ependymoma in that they are thought to arise from radial glial cells lining the ventricular system. However, they differ from adult ependymomas in which genes and chromosomes are most often affected, the region of the brain they are most frequently found in, and the prognosis of the patients. Children with certain hereditary diseases, such as neurofibromatosis type II (NF2), have been found to be more frequently afflicted with this class of tumors, but a firm genetic link remains to be established. Symptoms associated with the development of pediatric ependymomas are varied, much like symptoms for a number of other pediatric brain tumors including vomiting, headache, irritability, lethargy, and changes in gait. Although younger children and children with invasive tumor types generally experience less favorable outcomes, total removal of the tumors is the most conspicuous prognostic factor for both survival and relapse.
A central nervous system primitive neuroectodermal tumor, often abbreviated as PNET, supratentorial PNET, or CNS-PNET, is one of the 3 types of embryonal central nervous system tumors. It is considered an embryonal tumor because it arises from cells partially differentiated or still undifferentiated from birth. Those cells are usually neuroepithelial cells, stem cells destined to turn into glia or neurons. It can occur anywhere within the spinal cord and cerebrum and can have multiple sites of origins, with a high probability of metastasis through cerebrospinal fluid (CSF).
In histopathology, a palisade is a single layer of relatively long cells, arranged loosely perpendicular to a surface and parallel to each other. A rosette is a palisade in a halo or spoke-and-wheel arrangement, surrounding a central core or hub. A pseudorosette is a perivascular radial arrangement of neoplastic cells around a small blood vessel. Rosettes are characteristic of tumors.
Embryonal tumor with multilayered rosettes (ETMR) is an embryonal central nervous system tumor. It is considered an embryonal tumor because it arises from cells partially differentiated or still undifferentiated from birth, usually neuroepithelial cells, stem cells destined to turn into glia or neurons. It can occur anywhere within the brain and can have multiple sites of origins, with a high probability of metastasis through cerebrospinal fluid (CSF). Metastases outside the central nervous system have been reported, but remain rare.