Introduction of neurofibromatosis
Neurofibromatosis or von Recklinghausen´s disease is characterized by multiple café-au-lait spots early in life, multiple subcutaneous or cutaneous neurofibromas, optic glioma, iris hamartomas (LISCH nodules), and specific dysplastic bone lesions (sphenoid dysplasia, pseudarthrosis, or scoliosis). The patients may develop sarcomatoid degeneration of neurofibromas (rhabdomyosarcoma), malignant peripheral nerve sheet tumors, and brain tumors.

Neurofibromatosis occurs in families without acoustic neuromas (neurofibromatosis type 1, NF1), and those with acoustic neuromas (neurofibromatosis type 2, NF2). NF1 affects1/4000 individuals, and is the most common familial cancer syndrome with predisposition to pheochromocytoma. The risk for pheochromocytoma is, however, low in NF1, only about 2%. In autopsy series the prevalence of pheochromocytomas has been 3-13%. Pheochromocytomas are not part of NF2. NF1 patients may suffer from macrocephaly, height retardation, and cognitive disorders. They may also present with duodenal carcinoid tumors (often in the Papilla Vateri), with positive staining for somatostatin, and they may have combinations of such carcinoids and pheochromocytoma. NF1 patients have also had the occasional co-occurrence with thyroid carcinoma.

Genetics of neurofibromatosis
NF1 is an autosomal dominant trait with variable expression, and 50% of patients represent new mutations. The NF1 gene is a tumor suppressor gene mapped to chromosome 17q11.2. Because of the large gene size mutation analysis has been difficult, although recent reports have indicated that 70% of NF1 patients have truncation mutations. NF1 accounts for more than 90% of cases with neurofibromatosis. As many as 30-50% of NF1 patients represent new germ-line mutations and have no family history of neurofibromatosis. Specific mutations associated with pheochromocytoma have not been identified in NF1

Pheochromocytomas: Pheochromocytomas in NF1 occur at a later age than in MEN 2 and VHL, with a mean age at diagnosis of around 50 years, and seldom occur before 20 years of age. Approximately 10% of NF1 patients with pheochromocytoma have multiple or bilateral tumors. Extraadrenal pheochromocytomas are rare in NF1 (6%). Malignant pheochromocytomas, with metastases to liver, lung, and bone, are reported in 12%.

Clinical features/treatment of neurofibromatosis
NF1 has been associated with high incidence of spontaneous abortions. Undiagnosed pheochromocytomas in NF1 patients during pregnancy have caused high fetal and maternal mortality, and patients should be evaluated for pheochromocytoma before pregnancy is planned. Neurofibromatosis may be challenging for the anaesthesiologist due to facial deformity or presence of neurofibromas obstructing the airway, and possible adverse reactions to neuromuscular blockade. The treatment is surgical as for other pheochromocytomas.