Endocrine Abstracts

Introduction: Medullary thyroid carcinoma (MTC) accounts for 1-5% of all thyroid cancers. It is a neuroendocrine tumor arising from the calcitonin-secreting parafollicular cells of the thyroid. In rare cases, the neoplastic cells additionally secrete other substances, such as histamine, serotonin, ACTH, CRF etc, leading to paraneoplastic syndromes.

Case report: An 80 year old male presented to our Department with an already diagnosed metastatic MTC. Three years ago he had undergone a total thyroidectomy together with a right cervical lymph node dissection. His pre- and post-thyroidectomy calcitonin measurements were 2900 and 400pg/ml, respectively. Past medical history Rheumatoid arthritis At his present visit, he was in good clinical condition. Calcitonin and CEA were measured 3640pg/ml and 123ng/ml, respectively. Whole body imaging revealed metastatic lymph nodes on the right cervical area and the upper mediastinum, as well as multiple secondary liver lesions, larger than those shown in last imaging. Because of disease progression, the patient was commenced on Vandetanib (Tyrosine Kinase Inhibitor, TKI) 300 mg/d. One month later, he presented with an itchy maculopapular, exanthema, starting from face and upper extremities and extending rapidly to almost the whole body, with local exfoliation and inflamation and was barely tolerated by the patient. Antibiotics, antihistamines and local and systematic corticosteroids were administered, with almost no improvement. Vandetanib had to be discontinued for four months, during which the exanthema subsided to a great extent, while, concomittantly, melanchrosis appeared on the upper extremities and then almost everywhere on the body. In addition, the patient complained about proximal weakness and had oedema on lower extremities. Imaging and blood tests showed disease progression. There was suspicion of hypercortisolism which was confirmed by relevant tests and led to diagnosis of ECS. The patient was then administered Metopyrone 250 mg bid and Cabozatinib 40 mg/, which is a different TKI. Six months later, the patient is in good clinical condition, with almost no symptoms. Imaging and biochemical tests show stabilization of the disease.

Conclusion: At most 0,7% of patients with MTC are reported to develop ECS. MTC represents 2,2-7,5% of all causes of ECS. ECS rises morbidity and mortality of MTC, due to consequences of hypercortisolism. TKIs are considered as the first-line therapy for ECS in the setting of unresectable or progressive MTC.