Diagnosis

The diagnosis of neurofibromatosis is based on the clinical findings. Cardinal features are numerous cafe au lait spots - greater than six - and skin tumours. A positive family history in antecedent and collateral members makes diagnosis even more certain.

Positive family history and X-ray demonstration of bone cysts help diagnosis where cutaneous manifestations are less obvious, as in central neurofibromatosis and younger children. Evidence of precocious puberty, signs of involvement of cranial nerves - acoustic neuroma or optic glioma - and/or spinal nerves, centrally or peripherally, may also be sought.

A similar presentation with cafe au lait spots may be present in Allbright-McCune syndrome.

Prenatal diagnosis is not possible.