Endocrine Abstracts

A 43 year old hypertensive lady was referred to a surgical team at a tertiary oncology centre for consideration of completion thyroidectomy following removal of a nodule the histology of which had shown medullary thyroid carcinoma. She was reviewed in the cancer Multi-Disciplinary Team meeting; surgery was deferred until she had been reviewed in the endocrine clinic.

There was no known family history of MTC or other endocrine abnormality; however the patient has two children the oldest of whom had emergency surgery for Hirshsprung’s disease when newborn. The patient’s brother was also known to have had Hirshsprung’s and died at an early age. Genetic mutations in Hirschsprung’s disease are located throughout the RET proto-oncogene on chromosome 10.

She gave a history of palpitations, anxiety and occasional flushing for several years treated with a beta-blocker. Thyroid function tests, bone profile and three separate 24-hour urine collections for catecholeamines were normal. The urine collections were performed after stopping her beta-blocker for 6 weeks. An MIBG scan was also negative.

With no contra-indication to surgery, completion thyroidectomy has taken place with no complications. Molecular genetic analysis demonstrated a mutation in codon 620 (exon 10) of the RET proto-oncogene. This mutation is associated with both MEN-2A and Familial MTC. The daughter with corrected Hirshsprung’s carries the mutation as expected although the other sibling does not carry the mutation. Genetic counselling and screening continues for extended family members and discussions regarding prophylactic thyroidectomy in the affected sibling are also on-going.

This case illustrates the importance of considering genetic disease as a cause of medullary thyroid carcinoma and of taking a detailed family history. Furthermore, the important role of endocrinologists in thyroid cancer MDT meetings is highlighted.