Musculoskeletal Manifestations of Neurofibromatosis Type 1: a Pictorial Review

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NSK Ip, CY Lee, MK Yuen

Hong Kong J Radiol 2018;21:213-21

DOI: 10.12809/hkjr1816856

Neurofibromatosis type 1 (NF1) is a common neurocutaneous condition with an autosomal dominant pattern of inheritance. It affects multiple organ systems, and musculoskeletal abnormalities are seen in up to 50% of affected patients. Neurofibromas are the hallmark of NF1. Of the three types of neurofibromas (localised, diffuse, and plexiform), plexiform neurofibromas are pathognomonic of NF1. There is a lifetime risk (around 8% to 13%) for NF1 patients of developing malignant peripheral nerve sheath tumours from pre-existing neurofibromas. Plexiform neurofibromas may be associated with massive and disfiguring enlargement of an extremity, a condition referred to as elephantiasis neuromatosa. Dermal neurofibromas usually appear as circumscribed masses on plain radiographs and cross-sectional imaging. In the axial skeleton, NF1 can affect the orbit (sphenoid wing dysplasia), chest wall (ribbon ribs deformity/thinned ribs), or spine (non-dystrophic and dystrophic scoliosis, dural ectasia). One of the most common manifestations in the appendicular skeleton is anterolateral bowing of the tibia with formation of pseudarthrosis after bowing fracture. NF1 is the most common phakomatosis and affects multiple organ systems; nearly all parts of the skeleton and surrounding soft tissues can be involved. Radiologists should be familiar with the different imaging manifestations of NF1.


Author affiliation(s):
NSK Ip, CY Lee, MK Yuen: Department of Radiology, Tuen Mun Hospital, Tuen Mun, Hong Kong