Endocrine Abstracts

Background: Cushing’s syndrome (CS) in medullary thyroid cancer (MTC) is rare with less than 60 cases reported. Less than 1% of MTC develop ectopic ACTH-dependent CS and this correlated with metastasis at diagnosis and poor prognosis.

Case presentation: A 32-year-old male was referred to our department for suspected CS. Initial evaluation showed hypokalemia(2.4 mmol/l) and severe ACTH-dependent CS (Cortisol h8:678ng/ml; ACTH:249pg/ml; urinary free cortisol:13827mg/24h, night salivary cortisol:16.7mg/dl; cortisol after 1 mg-dexamethasone:750ng/ml). Both 8 mg-dex suppression test and CRH stimulation were indicative of ectopic CS. Thyroid ultrasound was suspicious for cancer with cervical lymph nodes metastasis. MTC was confirmed by citology, calcitonin >20.000pg/ml and CEA 3054.2ng/ml. Urinary metanephrines and germline RET analysis were normal. Gallium-68 PET/CT revealed metastases in bone, lungs and liver. The patient developed worsening hypokalemia, despite I.V. KCl 120mEq/day and canrenone 200 mg bid, and severe psychiatric symptoms that required urgent bilateral adrenalectomy. Intraoperative liver biopsy showed localization of MTC with ACTH expression at immunohistochemistry. After surgery the patient started cortisol and fludrocortisone therapy and had a rapid recovery. He later underwent total thyroidectomy with bilateral cervical node dissection. Histology confirmed multifocal MTC with infiltration of the left laryngeal recurrent nerve (pT4aN1b). Systemic therapy with lanreotide 120 mg/28 days and vandetanib 300 mg/day was initiated. At 6 months, CT scan showed stable disease. The patient is in good clinical conditions and is continuing treatment.

Conclusion: This case underlines the effectiveness of emergency bilateral adrenalectomy for management of severe hypercortisolism. Improvement in patient conditions allowed initiation of therapy for MTC. Considering the severe evolution of MTC with ectopic CS, we preferred systemic treatment for this young patient.