Minimising a bleeding problem: Management of a rare cause of a mediastinal mass with percutaneous embolisation prior to surgery.
S.S. Hussain1, R. Woolf1, D. Patel1, J. Jackson2, V. Anikin3, K. Meeran1
1Department of Endocrinology, Hammersmith Hospital; 2Department of Radiology, Hammersmith Hospital; 3Department of Thoracic Surgery, Harefield Hospital
A 37 year African man presented to his local hospital with a 2 month history of dry cough, excessive sweating and 10 kilogram weight loss. A large mediastinal mass was discovered on plain chest radiography. This was confirmed on CT imaging as a 10 x 8 x 6 cm central mass in the precarinal area. He was treated empirically for presumed tuberculosis (TB). There was no improvement in the size of the mass. Sputum and bronchial washing cultures for TB were negative. Mediastinoscopy revealed a vascular lesion, which bled on biopsy. Histology revealed blood only. Similar results were obtained on repeat bronchial and CT guided biopsies. Multidisciplinary review of his imaging revealed an unusual pattern of enhancement with striated peripheral appearance and central necrotic core. The possibility of a paraganglioma was subsequently proposed and the patient was referred for endocrine investigation. He remained normotensive throughout his investigations. Endocrine tests revealed normal 24 hour urine and plasma metanephrines and normal fasting gut hormones. I123-MIBG scintigraphy demonstrated increased uptake in the mediastinal region supporting the possibility that the mass originated from neural crest tissue.
The patient underwent alpha-blockade using phenoxybenzamine. Pre-operative percutaneous embolisation was arranged. Angiography confirmed a highly vascular mediastinal mass. The arterial supply of the lesion was anomalous and derived from several hypertrophied vessels. All of these vessels were selectively catheterised and the tumour was embolised with polyvinyl alcohol. A median sternotomy was performed 48 hours after embolisation with ongoing adrenergic blockade. A large tumour behind the ascending aorta was successfully mobilised and fully resected. Histology revealed a well circumscribed tumour with no evidence of invasion. The tumour stained positively for chromogranin, NCAM and S100 confirming a paraganglioma, which in this case was non-secretory. The patient made an uneventful recovery and is currently awaiting genetic investigations for mutations in succinate dehydrogenase subunit genes.
Our case illustrates the importance of considering paraganglioma in the differential diagnosis of mediastinal masses if characteristic radiological appearances, as described here, are present or if symptoms suggesting catecholamine excess are present. These hypervascular tumours have the propensity to bleed and invade surrounding vascular structures, making surgical resection technically challenging if the correct diagnosis is missed. Multidisciplinary management of mediastinal paragangliomas with pre-operative embolisation and adrendergic blockade should be routinely considered to improve the chance of curative surgical intervention and minimise operative complications.