A rare case of ectopic Cushing syndrome presenting with weight loss

Abstract

Introduction

Cushing's Syndrome (CS) due to ectopic ACTH release, ectopic ACTH syndrome (EAS) is a rare cause of ACTH-dependent CS. Although many malignancies are associated with EAS, the most common of these is neuroendocrine tumors of the lung. EAS-induced hypercortisolism has a rapid onset and has serious life-threatening clinical consequences. The recommended first-line treatment of EAS is the surgical removal of the ectopic ACTH-secreting tumor (EAT). Despite improved imaging techniques, 10–30% of EATs cannot be located by first-line imaging methods and often require secondary evaluation or functional imaging techniques.

Clinical Case

A 26-year-old male patient with no known comorbidities, refers with complaints of weight loss, proximal muscle weakness, fatigue, dizziness, decreased voluntary attention and erectile dysfunction for 2 months. In the initial assessment, his blood pressure was 170/100 mmHg, pulse rate 85 bpm, body mass index was 24,8 kg/m2, ın physical examination nothing remarkable except dark coloured striae larger than 1 cm in the abdomen. There was no history of drug or herbal substance use. In the laboratory evaluation of the patient, hypokalemia and high fasting blood sugar were detected. The plasma ACTH and cortisol levels were elevated. 24-hour urinary free cortisol level was high. The diurnal rhythm of the cortisol was disturbed. Thereupon, no suppression was observed in blood and urine cortisol levels in the suppression test of 1 mg, 2 mg and 8 mg dexamethasone, respectively (Table 1). In the high-resonance CT imaging of the patient with suspected ectopic ACTH release, no tumor was detected in the first examination. CT imaging of the abdomen and pelvis revealed hyperplasia in the bilateral adrenal glands and an irregularly shaped nodule of approximately 7.5 mm in diameter, adjacent to the right lung lower lobe bronchus in the cross-sectional area. Gallium 68 DOTATATE PET CT was performed. In the nodular area at the base of the right lung, an increased activity was detected with a SUVMAX of 3.1. The patient was evaluated on the multidisciplinary endocrinology board and it was decided to perform a right lung lower lobectomy. The pathology result was reported as typical carcinoid tumor. A 100% ACTH positivity was detected in the immunohistochemically examination(Figure 1). Short-term low-dose steroid treatment was given to prevent adrenal insufficiency in the postoperative period. When the patient was evaluated with clinical and laboratory findings in the 3rd month, it was seen that cure was obtained in terms of CS.

Conclusion

As this case shows, EAS management is a rare condition that requires a multidisciplinary approach and can be difficult to diagnose and treat. Although weight loss appears paradoxical with CS, malignancy-related weight loss should also be considered. Early and accurate management is vital because of its course that can cause rapid clinical deterioration.