ESPE Abstracts

Background: Phaeochromocytoma is a rare neuroendocrine tumour originating from chromaffin cells in the adrenal medulla and less commonly from extra-adrenal paraganglia. Phaeochromocytoma occur in the context of a genetic syndrome in approximately 50% of adults and 80% of children. Genetic testing of index cases enables testing of first-degree relatives, identification of children who inherit the gene change and surveillance, early diagnosis and treatment of associated tumours. We present two children with phaeochromocytoma associated with SDHB gene changes, who were diagnosed on routine surveillance. We contrast their clinical picture with their affected mothers who also developed phaeochromocytoma in childhood. In doing so, we underscore the value of predictive genetic testing in childhood.

Case 1: Nor-metadrenaline concentration was elevated (3.14nmol/L, normal range <1.18) on annual surveillance in an asymptomatic 12.5-year-old female. She inherited a SDHB gene change (136C>T) from her mother who developed malignant phaeochromocytoma age five years. MRI identified a 2x2 cm right pheochromocytoma. 24-hour ambulatory blood pressure monitoring (ABPM) showed mild hypertension and loss of nocturnal dipping. Treatment included preoperative α then β blockade with low dose phenoxybenzamine (10 mg BD), atenolol (25 mg daily), and volume expansion. She underwent laparoscopic resection of the phaeochromocytoma and was discharged without anti-hypertensive therapy. There was no evidence of extra-adrenal disease on DOTATATE PET CT and histology showed benign features.

Case 2: Nor-metadrenaline concentrations were elevated (4.5nmol/L, normal range <1.07) on annual surveillance in an asymptomatic 6-year-old male. He had inherited a change in the SDHB gene (c.379dup) from his mother, who presented with severe hypertension age 11 years and was diagnosed with phaeochromocytoma. Following surgery, she experienced prolonged hypotension, managed on intensive care. He was normotensive on ABPM. MRI showed a 2 × 1.3cm mass. Preoperative treatment with α then β blockade (prazosin 200mcg and propranolol 5 mg TDS) and volume expansion preceded laparoscopic resection of the phaeochromocytoma. He was discharged after four days without anti-hypertensive therapy. Histology showed benign features. Plasma nor-metanephrine returned to normal (0.66nmol/L) and there was no recurrence or new lesions on MRI.

Discussion: In contrast to their mothers, these two children were diagnosed before the onset of symptoms. There was minimal disruption to their blood pressure, complete surgical resection was achieved and recovery was uneventful.

Conclusion: Careful surveillance of children with SDHB gene changes may enable diagnosis of phaeochromocytoma in the preclinical phase, leading to a reduction in morbidity.