A 42-year-old male with neurofibromatosis type 1 (NF1) characterised by skin neurofibromas and café-au-lait spots presented to the emergency department with sudden onset left neck swelling after coughing. CT angiogram demonstrated a large haematoma secondary to rupture of a left external carotid artery branch. He underwent surgery for repair of the ruptured artery; however, immediately postoperatively, a coughing fit following extubation resulted in re-bleed necessitating repeat surgical intervention. Histopathology of the operative specimen demonstrated arterial vessel with invading neurofibroma. Postoperatively in ICU, despite the use of multiple antihypertensives, including high dose IV labetalol, perindopril, metoprolol, prazosin and GTN patch, the patient’s systolic blood pressure was intermittently >200 mmHg.
Given his background of NF1 and significant hypertension, the patient was investigated for a phaeochromocytoma. Plasma normetadrenaline was 5225 pmol/L (reference range <900 pmol/L) and metadrenaline was 7998 pmol/L (<500 pmol/L). CT demonstrated a right-sided 3.7cm adrenal mass consistent with a phaeochromocytoma. Following Endocrinology review, phenoxybenzamine and diltiazem were commenced with cessation of all other antihypertensive agents. He was discharged day 10 postoperatively and is awaiting phaeochromocytoma resection. In retrospect, he denied any symptoms suggestive of a phaeochromocytoma.
His mother was the index case and his only sibling who also had NF1 died in her 30s of a presumed ruptured aorta.
Discussion
NF1 is an autosomal dominant condition caused by a vast number of pathogenic variants in the NF1 gene. The estimated incidence is ~ 1/1,900–1/3,500 people worldwide, of whom approximately 3% develop a phaeochromocytoma. The less commonly appreciated association between NF1 and vascular abnormalities include rupture and invasion by neural tumours. Significant hypertension in those with a phaeochromocytoma may represent a phaeochromocytoma crisis, even in those who were otherwise apparently asymptomatic. A high level of suspicion for phaeochromocytoma is therefore crucial in those with genetic predispositions and hypertension.