Plexiform neurofibroma in Adult
PNF are associated with neurofibromatosis type I (NF1) and are considered pathognomonic for this condition. A single plexiform neurofibroma is a single criterion for NF1 (at least two of seven criteria are required for diagnosis). About one-fourth of children with NF1 develop PNF. Facial PNF usually appear within the first 3 years of life and often involve the trigeminal nerve.
Unlike cutaneous and subcutaneous neurofibromas, PNF are unaffected by hormonal changes during puberty or pregnancy. PNF may be asymptomatic but may also cause morbidity because of a propensity to infiltrate surrounding tissue. Complications arise from compression of surrounding structures, which can induce pain, neurologic impairment, motor dysfunction, and cause disfigurement. Rarely PNF can result in death from such complications. PNF carry an approximate 10% risk of developing into malignant peripheral nerve sheath tumors.
D36.10 – Benign neoplasm of peripheral nerves and autonomic nervous system, unspecified
403818001 – Plexiform neurofibroma
Differential Diagnosis & Pitfalls
- Congenital or giant melanocytic nevi – Hyperpigmented smooth or verrucous macules, papules, or plaques
- Becker nevus – Large, hyperpigmented, solitary patches with hypertrichosis commonly on the shoulder or trunk of men
- Congenital smooth muscle hamartoma – Skin-colored or hyperpigmented plaque often with increased villous or terminal hairs
- Klippel-Trenaunay-Weber syndrome – Three characteristic features include port-wine stain, abnormal overgrowth of soft tissue and bone, and venous malformations
- Proteus syndrome (Wiedemann syndrome) – Presents with multiple tumors throughout the body, increasing with age
- Lipomatosis / lipoma – Well-circumscribed tumors with little to no surface changes or associated symptoms
- Neurofibroma – Firm or semi-firm papules or nodules that may invaginate or exhibit the "button hole" sign following palpation or compression from above the lesion