Discrete subcutaneous neurofibromas: Lie below and look like bumps on the skin, which can sometimes be tender. Deep nodular neurofibromas: Involving tissues and organs underneath the dermis, but otherwise resembling cutaneous and subcutaneous neurofibromas. Age of onset
Dermal neurofibromas typically arise in the teenage years and are often associated with the onset of puberty. In people with Neurofibromatosis Type I,  they tend to continue to increase in number and size throughout adulthood, although limits exist as to how big they get, and cases progress at highly variable rates. Medical complications
Dermal neurofibromas can lead to stinging, itching, pain, and disfigurement. No evidence of malignant transformation has been found. Plexiform neurofibroma
Anatomy
Plexiform neurofibromas can grow from nerves in the skin or from more internal nerve bundles, and can be very large. Internal plexiform neurofibromas are very difficult to remove completely because they extend through multiple layers of tissue and the attempt would damage healthy tissue or organs. Age of onset
Plexiform neurofibromas occur earlier in life and are thought to be congenital defects. Medical complications
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. Plexiform neurofibroma is a known precursor for MPNST in NF1 patients. 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.
There has even been a documented case of a Schwannoma being induced from a neurofibroma due to radiation therapy. Medications
ACE inhibitors have been 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. No effect
Pirfenidone inhibits fibroblast growth. Studies showed no improvement over controls. Tipifarnib (also known as drug R115777) inhibits the activation of RAS. This drug is a Farnesyltransferase inhibitor which inhibits the Ras kinase in a post translational modification step before the kinase pathway becomes hyperactive. It successfully passed phase one clinical trials but was suspended (NCT00029354) in phase two after showing no improvement over controls. Research
The many drug therapies under study for neurofibromas are in various stages of research; more time will be required to determine if these are viable options for the treatment of neurofibromas.