Internal spinal mass such as spinal astrocytoma, ependymoma, schwannoma, neurofibroma, and achondroplasia causes vertebrae scalloping.
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The differential diagnosis of a dermatofibroma includes neurilemmoma, neurofibroma, piloleiomyoma, cyst, hypertrophic scar, and tophus.
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This section discusses the tumorigenesis of neurofibroma in terms of genetics, cell signaling, histology and the cell cycle.
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The differential diagnosis for PEN includes a neurofibroma, basal cell carcinoma, melanocytic nevus, epidermoid cyst and a skin appendage.
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Once a plexiform neurofibroma has undergone malignant transformation, radiation and chemotherapy can be used as treatment. However, radiation is generally not used as a treatment for plexiform neurofibromas because of concerns that this could actually promote malignant transformation. There has even been a documented case of a Schwannoma being induced from a neurofibroma due to radiation therapy.
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Histopathologic image of cutaneous neurofibroma obtained by biopsy A blood test for protein melanoma inhibitory activity may be used to detect the presence of neurofibromas.
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A solitary neurofibroma (also known as a "Solitary nerve sheath tumor," and "Sporadic neurofibroma") may be 2 to 20mm in diameter, is soft, flaccid, and pinkish-white, and frequently this soft small tumor can be invaginated, as if through a ring in the skin by pressure with the finger, a maneuver called "button-holing."James, William; Berger, Timothy; Elston, Dirk (2005). Andrews' Diseases of the Skin: Clinical Dermatology. (10th ed.). Saunders. .
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Juvenile variety xanthogranuloma can be distinguished from xanthoma by the spread of the lesion and the lack of lipid abnormalities. Other similar diagnoses include molluscum contagiosum, hemangioma and neurofibroma.
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"A Phase II Trial of Peginterferon Alpha-2b (Pegintron) for Neurofibromatosis Type 1 Related Unresectable, Symptomatic or Life-Threatening Plexiform Neurofibromas", National Institutes of Health study 08-C-0130 Sorafenib is being studied for treatment of unresectable plexiform neurofibroma and low-grade astrocytomas. In vitro, tranilast, inhibits growth of neurofibroma cells. Gene therapy for the neurofibromin 1 gene represents the ultimate solution to preventing the cluster of maladies which are enabled by the mutation.
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This condition is called hyperplasia, which is cell growth beyond what is normally seen. However, despite increased numbers of nonmyelinating Schwann cells, there is no neurofibroma yet. In order for the neurofibroma to develop, cells that are heterozygous for the NF1 gene must be recruited to the site. It has been hypothesized that the proliferating nonmyelinating Schwann cells secrete chemoattractants such as the KIT ligand, and angiogenic factors such as the heparin-binding growth factor midkine.
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Neurothekeoma histology slide Neurothekeoma is a benign cutaneous tumor 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", 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". Clinically, neurothekeomas present as a solitary nodule of the skin.
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The tumor is quite unique, but other tumors are considered in the differential diagnosis histologically. They included pleomorphic adenoma, myoepithelioma, myxoid neurofibroma, neurothekeoma (nerve sheath myxoma), chondroid choristoma, extraskeletal myxoid chondrosarcoma, focal oral mucinosis, and an ossifying fibromyxoid tumor of soft parts.
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In 1999, McKinnon treated a Michigan woman with a large tumor disorder, neurofibroma, at the University of Chicago. He successfully removed her 200-pound tumor in an 18-hour operation that drew worldwide attention, according to USA Today. Dr. McKinnon was subsequently featured on the Oprah Winfrey Show for successfully removing the world’s biggest solid tumor. In 2004, McKinnon was invited on a special mission to Romania to treat a similar patient with a giant neurofibroma tumor. With a team of doctors, he performed a 10-hour operation and successfully removed an 80-pound tumor from a 47-year-old woman that suffers from a genetic disorder causing tumors to grow on her body, according to BBC News.
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Image of neurofibroma showing myxoid appearance Plexiform neurofibromas occur earlier in life and are thought to be congenital defects."Case Based Pediatrics For Medical Students and Residents: Chapter XVIII.11. Neurofibromatosis", by Vince K. Yamashiroya, MD. August, 2002. Department of Pediatrics, University of Hawaii John A. Burns School of Medicine.
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Neurofibromas have been subdivided into two broad categories: dermal and plexiform. Dermal neurofibromas are associated with a single peripheral nerve, while plexiform neurofibromas are associated with multiple nerve bundles. According to the World Health Organization classification system, dermal and plexiform neurofibromas are grade I tumors. Plexiform neurofibroma are more difficult to treat and can transform into malignant tumors.
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Neurofibroma of the skin. Patient suffering from Recklinghausen's disease. Klaus D. Peter, Gummersbach, Germany Neurofibromatosis Type I is a genetic disorder, caused by the affected individual inheriting one copy of a mutant gene and one normal gene on a pair of autosomal chromosomes. The condition results in multiple neurofibromas (benign nerve-sheath tumours in the peripheral nervous system), and occasionally neurilemmomas.
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A pseudorosette is a perivascular radial arrangement of neoplastic cells around a small blood vessel. Pseudorosettes are present in neuroblastoma, medulloblastoma, malignant melanoma, ependymoma, Merkel cell carcinoma, neuroendocrine tumor of skin, seborrheic keratosis, dendritic cell neurofibroma, astroblastoma, large cell neuroendocrine tumor of cervix, clear cell ependymoma of spinal cord, celiac disease, nasal tumor of olfactory origin, rosette forming glioneural tumor (RGNT), oncocytoma, Wilm’s tumor, pheochromocytoma of urinary bladder.
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Plexiform neurofibroma can cause disfigurement, neurological, and other clinical deficits. Plexiform neurofibromas have the potential to cause severe clinical complications if they occur in certain areas. About 10% of plexiform neurofibromas undergo transformation into a malignant peripheral nerve sheath tumor. The formation of malignant cancers from neurofibromas is associated with the loss of expression of the CDKN2A or TP53 gene in nonmyelinating Schwann cells that also exhibit biallelic inactivation of the NF1 gene.
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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. Neurofibromas arise from nonmyelinating-type Schwann cells that exhibit biallelic inactivation of the NF1 gene that codes for the protein neurofibromin.
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These chemicals promote the migration of different kinds of cells that are heterozygous for the NF1 gene into the hyperplastic lesions created by the nonmyelinating Schwann cells. These cell types include fibroblasts, perineurial cells, endothelial cells, and mast cells. The mast cells then secrete mitogens or survival factors that alter the developing tumor microenvironment and result in neurofibroma formation. Dermal and plexiform neurofibromas differ in later development stages, but the details are unclear at this point.
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Neurofibromas arise from nonmyelinating Schwann cells that only express the inactive version of the NF1 gene, which leads to a complete loss of expression of functional neurofibromin. While one defective allele may be inherited, loss of heterozygosity (LOH) must occur before a neurofibroma can form; this is called the ‘two-hit hypothesis’. This LOH happens by the same mechanisms, such as oxidative DNA damage, that causes mutations in other cells. Once a nonmyelinating Schwann cell has suffered inactivation of its NF1 genes, it begins to proliferate rapidly.
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A 34-year- old female was admitted with a slowly growing nodular lesion at the left nasolabial region for three years. (Tural, Selçukbiricik, Günver, Karışmaz, and Serdengecti, 2013) Written by Tural Selçukbiricik, Günver, Karışmaz, and Serdengecti, this report investigates the case of a slow growing bump on the face of a thirty-four-year-old woman. After undergoing an excisional biopsy, it was revealed that the nodule had developed into neurofibroma. Originally the patient had undergone excision however she sustained recurrence in under a year of the surgery.
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Typically, the lesions are suspected to be schwannomas or neurofibromas clinically with PEN being an incidental finding on histology. PEN is typically diagnosed in patients between the ages of 40 and 60 years and occurs more frequently in females than males. The diagnosis of PEN may be difficult, even with confirmatory histology, due to its histological similarities with schwannomas and neurofibromas. It is imperative that the correct diagnosis is made the misdiagnosis of a neurofibroma may lead to unnecessary further investigation into associated systemic syndromes such as neurofibromatosis type 1 or multiple endocrine neoplasia syndrome.
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There are exceptions to the two-hit rule for tumor suppressors, such as certain mutations in the p53 gene product. p53 mutations can function as a dominant negative, meaning that a mutated p53 protein can prevent the function of the natural protein produced from the non-mutated allele. Other tumor-suppressor genes that do not follow the two-hit rule are those that exhibit haploinsufficiency, including PTCH in medulloblastoma and NF1 in neurofibroma. Another example is p27, a cell-cycle inhibitor, that when one allele is mutated causes increased carcinogen susceptibility.
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Common pathological sources of PCS include Friedreich's Ataxia, an autosomal- recessive inherited disease, and tumors such as astrocytoma, ependymoma, meningioma, neurofibroma, sarcoma, and schwannoma. Illustration of an axon with a degenerated myelin sheath Cobalamin, commonly known as vitamin B12, plays a crucial role in the synthesis and maintenance of myelin in neurons found in the spinal cord. A deficiency of this essential vitamin results in demyelination, a deterioration of the axon's layer of insulation causing interrupted signal transmission, with a currently unknown specificity to the posterior region. PCS may develop with the failure to treat syphilis.
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Interestingly, even after oncogenic activation of a tissue, several researchers have identified a senescent phenotype. Researchers have identified a senescent phenotype in benign lesions of the skin carrying oncogenic mutations in neurofibroma patients with a defect that specifically causes an increase in Ras. This finding has been highly reproducible in benign prostate lesions, in melanocytic lesions of UV-irradiated HGF/SF-transgenic mice, in lymphocytes and in the mammary gland from N-Ras transgenic mice, and in hyperplasias of the pituitary gland of mice with deregulated E2F activity. The key to these findings is that genetic manipulations that abrogated the senescence response led to full-blown malignancy in those carcinomas.
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A nerve may be compressed by prolonged or repeated external force, such as sitting with one's arm over the back of a chair (radial nerve), frequently resting one's elbows on a table (ulnar nerve), or an ill-fitting cast or brace on the leg (peroneal nerve). Part of the patient's body can cause the compression and the term entrapment neuropathy is used particularly in this situation. The offending structure may be a well-defined lesion such as a tumour (for example a lipoma, neurofibroma or metastasis), a ganglion cyst or a haematoma. Alternatively, there may be expansion of the tissues around a nerve in a space where there is little room for this to occur, as is often the case in carpal tunnel syndrome.
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