Neurofibromatosis (NF) is a group of three conditions in which tumors grow in the nervous system. The three types are neurofibromatosis type I (NF1), neurofibromatosis type II (NF2), and schwannomatosis. In NF1 symptoms include light brown spots on the skin, freckles in the armpit and groin, small bumps within nerves, and scoliosis. In NF2, there may be hearing loss, cataracts at a young age, balance problems, flesh colored skin flaps, and muscle wasting. In schwannomatosis there may be pain either in one location or in wide areas of the body. The tumors in NF are generally non-cancerous.
Nervous tissue, also called neural tissue, is the main tissue component of the nervous system. The nervous system regulates and controls body functions and activity. It consists of two parts: the central nervous system (CNS) comprising the brain and spinal cord, and the peripheral nervous system (PNS) comprising the branching peripheral nerves. It is composed of neurons, also known as nerve cells, which receive and transmit impulses, and neuroglia, also known as glial cells or glia, which assist the propagation of the nerve impulse as well as provide nutrients to the neurons.
Neurofibromatosis type I (NF-1), or von Recklinghausen syndrome, is a complex multi-system human disorder caused by the mutation of Neurofibromin 1, a gene on chromosome 17 that is responsible for production of a protein (neurofibromin) which is needed for normal function in many human cell types. NF-1 causes tumors along the nervous system which can grow anywhere on the body. NF-1 is one of the most common genetic disorders and is not limited to any person's race or sex. NF-1 is an autosomal dominant disorder, which means that mutation or deletion of one copy of the NF-1 gene is sufficient for the development of NF-1, although presentation varies widely and is often different even between relatives affected by NF-1.
The International Classification of Diseases for Oncology (ICD-O) is a domain-specific extension of the International Statistical Classification of Diseases and Related Health Problems for tumor diseases. This classification is widely used by cancer registries.
Neurofibromatosis type II is a genetic condition that may be inherited or may arise spontaneously, and causes benign tumors of the brain, spinal cord, and peripheral nerves. The types of tumors frequently associated with NF2 include vestibular schwannomas, meningiomas, and ependymomas. The main manifestation of the condition is the development of bilateral benign brain tumors in the nerve sheath of the cranial nerve VIII, which is the "auditory-vestibular nerve" that transmits sensory information from the inner ear to the brain. Besides, other benign brain and spinal tumors occur. Symptoms depend on the presence, localisation and growth of the tumor(s), in which multiple cranial nerves can be involved. Many people with this condition also experience vision problems. Neurofibromatosis type II is caused by mutations of the "Merlin" gene, which seems to influence the form and movement of cells. The principal treatments consist of neurosurgical removal of the tumors and surgical treatment of the eye lesions. Historically the underlying disorder has not had any therapy due to the cell function caused by the genetic mutation.
A neurofibroma is a benign nerve-sheath tumor in the peripheral nervous system. In 90% of cases, they are found as stand-alone tumors, while the remainder are found in persons with neurofibromatosis type I (NF1), an autosomal-dominant genetically inherited disease. They can result in a range of symptoms from physical disfiguration and pain to cognitive disability.
The S100 proteins are a family of low molecular-weight proteins found in vertebrates characterized by two calcium-binding sites that have helix-loop-helix ("EF-hand-type") conformation. At least 21 different S100 proteins are known. They are encoded by a family of genes whose symbols use the S100 prefix, for example, S100A1, S100A2, S100A3. They are also considered as damage-associated molecular pattern molecules (DAMPs), and knockdown of aryl hydrocarbon receptor downregulates the expression of S100 proteins in THP-1 cells.
Schwannomatosis is an extremely rare genetic disorder closely related to the more-common disorder neurofibromatosis (NF). Originally described in Japanese patients, it consists of multiple cutaneous schwannomas, central nervous system tumors, and other neurological complications, excluding hallmark signs of NF. The exact frequency of schwannomatosis cases is unknown, although some populations have noted frequencies as few as 1 case per 1.7 million people.
neurofibromatosis 1 (NF1) is a gene in humans that is located on chromosome 17. NF1 codes for neurofibromin, a GTPase-activating protein that negatively regulates RAS/MAPK pathway activity by accelerating the hydrolysis of Ras-bound GTP. NF1 has a high mutation rate and mutations in NF1 can alter cellular growth control, and neural development, resulting in neurofibromatosis type 1. Symptoms of NF1 include disfiguring cutaneous neurofibromas (CNF), café au lait pigment spots, plexiform neurofibromas (PN), skeletal defects, optic nerve gliomas, life-threatening malignant peripheral nerve sheath tumors (MPNST), pheochromocytoma, attention deficits, learning deficits and other cognitive disabilities.
Granular cell tumor is a tumor that can develop on any skin or mucosal surface, but occurs on the tongue 40% of the time.
A nerve sheath tumor is a type of tumor of the nervous system which is made up primarily of the myelin surrounding nerves. From benign tumors like schwannoma to high grade malignant neoplasms known as malignant peripheral nerve sheath tumors, peripheral nerve sheath tumors include a range of clearly characterized clinicopathologic entities. A peripheral nerve sheath tumor (PNST) is a nerve sheath tumor in the peripheral nervous system. Benign peripheral nerve sheath tumors include schwannomas and neurofibromas.
Malignant triton tumor (MTT) is a relatively rare, aggressive tumor made up of both malignant schwannoma cells and malignant rhabdomyoblasts. It is classified as a malignant peripheral nerve sheath tumor with rhabdomyosarcomatous differentiation.
A Neurothekeoma (NT) is a type of rare benign cutaneous tumor that usually develops on the head and neck. They often occur in the second and early third decades of life and tend to afflict women more frequently than men. First described by Gallager and Helwig, who proposed the term in order to reflect the presumed origin of the lesion from nerve sheath. Microscopically, the lesions described closely resembled the tumor, "nerve sheath myxoma (NSM)", an entity first described by Harkin and Reed. The latter had, through the years, been variously described as "bizarre cutaneous neurofibroma", "myxoma of nerve sheath", and "pacinian neurofibroma".
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).
Selumetinib (INN), sold under the brand name Koselugo, is a medication for the treatment of children, two years of age and older, with neurofibromatosis type I (NF-1), a genetic disorder of the nervous system causing tumors to grow on nerves. It is taken by mouth.
A rhabdomyoblast is a cell type which is found in some rhabdomyosarcomas. When found histologically, a rhabdomyoblast aids the diagnosis of embryonal, alveolar, spindle cell/sclerosing, and pleomorphic rhabdomyosarcomas; however, in a tumor, expression of the rhabdomyoblast phenotype is not the only factor in diagnosing a rhabdomyosarcoma. Mesenchymal malignancies can exhibit this phenotype as well. Immunohistochemistry techniques allow for the sensitive detection of desmin, vimentin, muscle specific actin, and MyoD1. Similarly the rhabdomyoblast phenotype can be detected morphologically. Rhabdomyoblasts are early stage mesenchymal cells, having the potential to differentiate into a wide range of skeletal cells. Each stage of differentiation exhibits unique and distinguishable histological characteristics. In its initial from, stellate cells with amphiphilic cytoplasm and ovular central nuclei are observed. Commonly referred to as rhabdoid features, the maturing rhabdomyoblast will likely exhibit low levels of eosinophilic cytoplasm in proximal distances to the nucleus. As maturation and differentiation progress, the cell's cytoplasmic levels of white blood cells increase; additionally, elongated shapes, commonly depicted as “tadpole”, “strap” and "spider cells", are observed. In the concluding phase of differentiation, the white blood cell rich cytoplasm appears bright and exhibits cross-striation. The highly regulated organization of actin and myosin microfilaments in contractile proteins results in this appearance.
Within medical ophthalmology, Intraocular schwannoma, also termed uveal schwannoma, is a type of schwannoma found in the eye. These tumors are almost always benign in nature and while malignant forms have been documented in other areas of the body, this has not been reported in the uveal region. Composed of Schwann cells, these masses are generally slow growing and can be found in the peripheral nerve tract, often around the head and neck.
An intraneural perineurioma is a rare benign tumor within the sheath of a single nerve that grows but typically does not recur or metastasize. These lesions are only composed of perineurial cells, cloned from a single cell. They are distinct from schwannoma and neurofibroma.
Biphenotypic sinonasal sarcoma is a newly recognized, very rare, low-grade malignant tumor of the nasal cavity, which was formerly probably included in fibrosarcoma and synovial sarcoma cases. It was incorporated into the fourth edition of the World Health Organization Classification of Head and Neck Tumours, published in 2017.
Brigitte C. Widemann is German-American pediatric oncologist. She is chief of the pediatric oncology branch and clinical deputy director of the center for cancer research at the National Cancer Institute. She is also the special advisor to the NCI director for childhood cancer.
