[Adrenal incidentaloma in neurofibromatosis type 1]

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%.

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.

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.