Introduction: Neurofibromatosis type 1 is one of the most common genetically transmitted diseases with a high index of spontaneous mutations and extremely varied and unpredictable clinical manifestations. It is diagnosed by the existence of certain clinical criteria. The presence of numerous localised cutaneous neurofibromas or a plexiform neurofibroma is virtually pathognomonic of neurofibromatosis type 1. The incidence of pheochromocytoma in neurofibromatosis type 1 is 0.1-5.7%.
Case outline: A 56-year old female patient was admitted for further evaluation of incidental adrenal tumour previously diagnosed on computerized tomography (CT). She had previously unrecognized neurofibromatosis type 1 and a clinical picture which could remind of pheochromocytoma. None of the catecholamine samples in 24 hr urine indicated functionally active pheochromocytoma. Chromogranin A was moderately increased. Decision for operation was made after performing the image techniques. Adrenal incidentaloma had features of pheochromocytoma on abdominal magnetic resonance imaging (MRI), with positive 131I-MIBG (iodine 131-labelled metaiodobenzylguanidine scintigraphy). After being treated with phenoxybenzamine and propranolol, she was operated on. The pathohistological finding showed the case of left adrenal pheochromocytoma.
Conclusion: Detailed diagnostic procedure for pheochromocytoma should be performed with patients having neurofibromatosis type 1 and adrenal incidentaloma. Pheochromocytomas are rare tumours with fatal outcome if not duly recognized and cured.