Endocrine Abstracts

A 45-year-old male known case of sporadic medullary thyroid carcinoma with metastasis to lymph nodes and bone. He underwent total thyroidectomy and modified neck dissection and external radiation in 2003. He was admitted with MTC which was progressive with rising calcitonin from 9000 to 40 000 μg/l. He underwent urgent tracheostomy and assessed by ENT and found to have bilateral vocal cord palsy. Patient improved; however on further assessment he was found to have severe proximal muscle weakness and he is unable to stand from sitting position.

Radiological investigations: Pituitary MRI is normal. MRI spine thoracic show multiple bony mets with no cord compression. Bilateral inferior petrosal sinus sampling (IPSS) for ACTH levels. CRH+vasopressin stimulation: ACTH 117 – max response 127 nmol/cortisol 1003 – max response 1045 nmol/l.

Discussion: The diagnosis is ACTH-dependant Cushing’s syndrome. The most likely the underlining cause of this condition in this patient is due to ectopic ACTH secretion by metastatic medullary thyroid carcinoma.