SDHB MUTATIONS IN A CHILD WITH PARAGANGLIOMA

A CASE REPORT

Abstract

INTRODUCTION
Paediatric paraganglioma (PGL), a rare endocrine tumor, originating from neural crest along sympathetic or parasympathetic chain, is highly associated with the syndromic presentation of MEN, NF1 or von HippelLindau, and the germline mutations that affect succinate dehydrogenase gene (SDH).

RESULTS
We described a 12-year-old girl who had insidious onset of heat intolerance, diaphoresis and palpitation for 1 year. Her symptoms were initially transient but became intense and associated with episodic attacks of abdominal pain and vomiting. She was hyperglycemic during admission with weight loss of 3 kg, polyuria and polydipsia for 2 months. Clinical examination revealed hypertension and a vague mass palpable over right lumbar region. CT abdomen showed a right retroperitoneal enhancing mass with vascular displacement and compression. Urine catecholamine revealed raised norepinephrine 1658.0 ug/ day (15-80). She was commenced on oral phenoxybenzamine with addition of oral metoprolol during the 2nd week. Her blood sugar was controlled with SC insulin. She had liberal intake of oral fluid and oral NaCl supplement up to 4.5 gram/day. PET scan (DOTANOC) showed somatostatin receptor avid primary disease with no distant metastasis. Laparotomy was performed and a well-circumscribed mass measuring 6 cm x 4 cm, which was not adherent to the kidney vessels, was resected successfully. Transient hypertensive crisis occurred during surgical resection and responded to bolus intravenous sodium nitroprusside. Postoperatively, she did not require SC insulin and antihypertensive medications. Histopathological findings are consistent with paraganglioma. Her genetic results showed heterozygous mutation in SDHB gene for a variant designated c136C>T.

CONCLUSION
All paediatric paraganglioma should ideally have mutation analysis. Higher risk of metastatic disease and tumor recurrence are associated with SDHB mutation. Regular follow-up and monitoring of plasma metanephrine and normetanephrine or 24 hour urinary fractionated metanephrines are warranted.