Endocrine Abstracts

Background: Medullary thyroid cancer is a rare neuroendocrine neoplasm that can secrete variety of hormones, including ACTH. Cushing syndrome due to ectopic ACTH secretion is a rare complication of medullary thyroid cancer, usually accociated with metastatic disease. Around 50 percent of patients with medullary thyroid carcinoma and ectopic Cushing syndrome die due to complications of hypercortisolism. Based on the aforementioned, efficient management of hypercortisolism is crucial.

Case presentation: A 44-year old female with history of metastatic medullary thyroid cancer presented with malaise, generalized oedema, hypertension, hirsutism, fragile skin and finger ulceration. Laboratory results showed marked hypokaliemia and hyperglicaemia. The diagnosis of Cushing syndrome due to ectopic ACTH secretion was made. The patient was initially treated with ketoconazole, followed by metyrapone and vandetanib. After introduction of metyrapone and vandetanib, a rapid decrease in serum cortisol and improvement of clinical symptoms were observed as well as the reduction of tumor metastases. As an adverse effect to vandetanib, the patient developed palmar-plantar erythrodysestesia. The rash resolved after topical cotrticosteroid treatment.

Conclusion: Management of Cushing syndrome in medullary thyroid carcinoma is challenging. Use of drugs, such as steroid inhibitors, is often unsuccessful and bilateral adrenalectomy is sometimes required. In recent years, the use of tyrosine kinase inhibitors, especially vandetanib, has been shown to successfully control hypercortisolism. Despite adverse effects, some of which are potenially serious, vandetanib is an important and efficient drug in the achievment of eucortisolism in patients with medullary thyroid cancer-related Cushing syndrome as well as in inducing tumor control.