<unk> s are benign nerve sheath tumors of neural origin in peripheral nervous system, comprising all elements of the peripheral nerve (i.e. axons, Schwann cells and fibroblasts) and can occur anywhere in the body.<unk> s may occur as part of the syndrome of<unk> tosis (most common), solitary<unk> s, or multiple<unk> s without von Recklinghausen's disease <unk> -1).<unk>  may be classified into further subtypes such as localized, cutaneous, subcutaneous, intraneural, intramuscular, diffuse, pigmented, and plexiform<unk> . However, plexiform<unk>  can be further subclassified into diffuse, and nodular plexiform<unk> . Gene involved in the pathogenesis of plexiform<unk>  is<unk> 1 which codes for<unk> n that leads to loss of RAS control causing increased activity of downstream RAS pathways involved in increased cell growth and survival. On gross pathology, a non-encapsulated superficial mass is the characteristic finding of localized or diffuse<unk> ; whereas the "bag of worms" appearance is the characteristic finding of plexiform<unk> . On microscopic histopathological analysis, nerve fibers, schwann cells, spindle cells with wavy nuclei without pleomorphism, shredded carrot collagen, moderate increase of cellularity vis-a-vis normal dermis, blood vessels, mast cells, pseudomeissnerian bodies, and varying degrees of myxoid degeneration are characteristic findings of<unk> . However, plexiform<unk>  shows a characteristic target sign on histopathology. It usually affects both men and women equally between the age of 20-40 years. Common symptoms of<unk>  include soft masses, transient itching, and transient pain with rest of the symptoms depending upon the involved site. There is no single diagnostic study of choice for<unk> , instead, it is diagnosed on the basis of medical history, physical examination, and imaging studies such as CT or MRI. The predominant therapy for<unk>  is surgical resection. Adjunctive chemotherapy and medications such as ACE inhibitors may be required. Prognosis of<unk>  is generally excellent. If left untreated, 10% of patients with plexiform<unk> s may progress to develop malignant peripheral nerve sheath tumor (MPNST).  Local recurrence occurs rarely.
Neurofibroma
Neuroma
Hemangioblastoma
Ameloblastoma
Ganglioneuroma
Ganglion cyst
PEComa
Brown tumor