Neurofibroma

These neoplasms may involve any area of the body, including bone or periosteum. Among bone lesions, the mandible, maxilla, vertebral column, tibia, fibula and humerus may be affected.

The tumours grow slowly and erode adjacent bone but rarely undergo malignant degeneration. Dumbbell-shaped lesions of the spine owing to widening of the intervertebral foramen are a common but nonspecific finding. CT scanning, MR imaging and ultrasonography are helpful in the diagnosis of these lesions. Neurofibromas are generally of low signal intensity on T1-weighted spin-echo MR images and of high signal intensity on T2-weighted images. MR imaging also allows identification of the nerve trunk of origin and the relationship of tumour to surrounding strctures.

Cirsoid or plexiform neurofibromas are benign tumours occurring only in neurofibromatosis but do have a potential for malignant degeneration. They may be seen in massively enlarged extremities (elephantiasis) and consist of soft tissue networks interdigitating with adjacent fat and muscle.

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