Endocrine Abstracts

Introduction: Papillary thyroid carcinoma is one of the most prevalent endocrine tumors. Adrenocorticotropic hormone (ACTH) dependent Cushing’s syndrome is a rare disease. We report a rare case of coexistence of papillary thyroid carcinoma and ACTH-dependent Cushing’s syndrome.

Observation: A 59-year-old man, was admitted to our endocrinology department for exploration of bilateral adrenal incidentalomas discovered in an abdominal CT scan done in the process of exploring portal hypertension. The patient was asymptomatic. The physical examination showed hypertension but no catabolic signs. Hormonal investigation revealed normal methoxylated derivatives plasmatic catecholamines, aldosteronemia and reninemia measurements. Diagnosis of ACTH-dependent cushing’s syndrome was made on the basis of lack of plasma cortisol response to low-dose dexamethasone suppression test at 126 nmol/l (above 50 nmol/l) and high plasmatic ACTH levels at 34 pg/ml (above 20 pg/ml). In order to locate the hypersecretion of ACTH (Cushing disease or an ectopic tumor), the patient underwent a High-dose Dexamethasone Suppression test. Cortisol level decreased greater than 50% after 8 mg of dexamethasone, suggesting Cushing disease. Pituitary MRI was normal. Therefore, we performed a body scan that showed a large thyroid nodule. Complementary cervical ultrasound showed an Eu-tirads 5 nodule. Fine needle aspiration was performed but was inconclusive (category III according to the Bethesda system). The patient underwent a total thyroidectomy. The pathological examination identified a papillary carcinoma of the thyroid.

Conclusion: There are few case reports on the coexistence of thyroid papillary carcinoma and ACTH dependent Cushing’s syndrome. The co-occurrence of two endocrine tumors with different origins is rare. Common physiopathology must be investigated.