Neurofibroma
Overview
is a benign nerve sheath tumor in the peripheral nervous system. Usually found in individuals with Neurofibromatosis Type 1 (NF1), a genetically-inherited disease, they can result in a range of symptoms from physical disfiguration and pain to cognitive disability. Neurofibromas arise from Schwann cells that exhibit biallelic inactivation of the NF1 gene that codes for the protein neurofibromin.[1] This protein is responsible for regulating the RAS-mediated cell growth pathway. In contrast to schwannomas, another type of tumor arising from Schwann cells, neurofibromas incorporate many additional types of cells and structural elements in addition to Schwann cells, making it difficult to identify and understand all the mechanisms through which they originate and develop.[2]
Symptoms
The list of signs and symptoms mentioned in various sources for Neurofibroma includes the 4 symptoms listed below: * Painless, slow-growing mass * Skin lump * Electric shock-like sensation when touching affected area * Surgery, regular monitoring Note that Neurofibroma symptoms usually refers to various symptoms known to a patient, but the phrase Neurofibroma signs may refer to those signs only noticable by a doctor.
Diagnosis
These home medical tests may be relevant to Neurofibroma: * Colon & Rectal Cancer: Home Testing o Home Colorectal Cancer Tests o Home Fecal Occult Bleeding Tests
Treatment
According to Packer, et al. in the article titled Plexiform neurofibromas in NF1-Toward biologic-based therapy, “There are several impediments that have limited progress in designing optimal therapies for NF1-associated neurofibromas, including a more complete understanding of 1) the contribution of each cell type in a neurofibroma to its genesis and continued growth, 2) the specific consequences of absent NF1 gene function on cell growth control, and 3) the role of additional genetic and biologic factors that influence neurofibroma formation and growth.” While this article was written prior to the papers cited in the Origin and Development of Neurofibromas section, these issues have not been totally addressed. While surgery is the most common method of treating neurofibromas, there are some alternative methods as well.Surgery Neurofibromas are commonly treated with surgical removal. Dermal neurofibromas are not usually removed unless they are painful or disfiguring, because there are generally so many of them and they are not dangerous. Removal of plexiform neurofibromas can be more difficult because they can be larger and cross tissue boundaries. However, besides pain, plexiform neurofibromas are sometimes removed due to the possibility of malignant transformation. One example of this can be found in the case study titled A case of isolated giant plexiform neurofibroma involving all branches of the common peroneal nerve, which discusses the removal of a large plexiform neurofibroma in the leg of a 6-year old male. The authors state: “Our case was operated, as both the cutaneous and deep branches of the peroneal nerve were involved causing pain and numbness in the leg, and because there was a possibility for malignant transformation, as growth in the mass was realized by the family members of the patient.” In layman’s terms, they decided to remove the neurofibroma because it was causing the boy pain and numbness in his leg, and because there was a possibility that it was undergoing a malignant transformation as his family noticed an increase in the tumor's size. The authors also note, “However, complete resection is quite difficult due to invasion of the tumor into the surrounding soft tissues.” [9] Sometimes plexiform neurofibromas form in locations that make them especially hard to access. One specific example of this can be found in a paper titled Surgical Treatment of a Left Ventricular Neurofibroma which chronicles the resection (partial removal) of a neurofibroma on the left ventricle. The neurofibroma was removed and the patient’s mitral valve had to be replaced. Another example of a neurofibroma in an unusual location is recorded in a paper titled Pelvic plexiform neurofibroma involving the urinary bladder. A 14-year-old girl with NF1 was diagnosed with a neurofibroma involving her bladder, a rare location.[10] These examples serve to illustrate that plexiform neurofibromas can form anywhere and can make surgical resection difficult. [edit] Radiation 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. [11] [edit] CO2 Laser CO2 lasers have been used to remove dermal neurofibromas. In a paper titled Hypertrophic Scars After Therapy with CO2 Laser for Treatment of Multiple Cutaneous Neurofibromas Ostertag et al. said this about treatment by laser: “The cosmetic disfigurement is the most important issue in the decision to treat cutaneous symptoms of neurofibromatosis. Treating patients with extensive neurofibromas with [a] CO2 laser is still the best choice. However, it is strongly advised that a test treatment be performed to judge the effectiveness of the procedure and whether the developed scar is an acceptable trade-off.” [12] [edit] Future Options There have been several proposed therapies for neurofibromas. These are in various stages of research; more time will be required to determine if these are viable options for the treatment of neurofibromas. In a letter to the editor of the Annals of Surgical Oncology by Dr. Hamid Namazi in 2008, ACE inhibitors were proposed as a novel treatment of neurofibromas. ACE inhibitors are currently used to treat hypertension and congestive heart failure, to avert remodeling and reinfarction after myocardial infarction, and to ameliorate diabetic nephropathy and other renal diseases. ACE inhibitors work by indirectly down regulating TGF-beta, which is a growth factor that has been shown to influence the development of tumors. [13] Based on the recent discovery that the nonmyelinating Schwann cells that make up Remak bundles are the origin of neurofibromas, it has been proposed that therapies for prevention and treatment be based on stabilizing the axon-Schwann cell interactions and reducing mast cell infiltration. As it appears that these elements are needed for neurofibroma formation, prevention or reduction could prove an effective treatment. [6]