Endocrine Abstracts

Introduction: Ectopic Cushing’s Syndrome (ECS) accounts for 5-10% of all cases of endogenous hypercortisolism. ACTH secreting intrathoracic masses is the most common cause of ECS. We present two patients with ectopic Cushing’s syndrome, with particularities in diagnosis.

Case 1:: A 59-year-old female presented with arterial hypertension, and osteoporosis, along with weight gain and facial plethora, starting two years before. Screening tests were consistent with Cushing’s syndrome, along with high plasma ACTH =81.8 pg/ml (range 10–60 pg/ml). Pituitary MRI was negative for adenoma. CRH stimulation test and selective inferior petrosal sinus sampling were compatible with ectopic ACTH secretion. 99 mTc-Tektrotyde scintigraphy scan showed increased radiotracer uptake in the left lower pulmonary lobe, and the finding was attributed to inflammatory causes since repeated thoracic CT and bronchoscopy were negative for any anatomic lesion. The patient was offered a trial with daily subcutaneous pasireotide, to which she responded. Subsequently, she remained in complete clinical and laboratory remission of hypercortisolism with a minimal dose of 300 mcg daily, and put under close surveillance for a two year period. Scintigraphy with Ga68 dotatoc demonstrated and confirmed the uptake in the lower left pulmonary field. The patient was subjected to thoracoscopic left lower lobectomy without complications. The histopathological examination revealed a typical bronchial carcinoid.

Case 2:: A 44-year-old man presented with arterial hypertension, facial plethora and mood changes introduced over a four-month period. He had no previous medical history, but reported daily alcohol consumption. Screening tests were diagnostic of Cushing’s syndrome with plasma ACTH 95.1 pg/ml (range 10–60 pg/ml). However, upon hospital admission for verification of the diagnosis, all repeat tests returned normal. A third admission after 3 weeks confirmed the presence of cyclic ACTH dependent Cushing’s syndrome, with ectopic origin according to CRH test. Pituitary MRI was negative for the presence of adenoma. Chest CT revealed a mediastinal mass of 2.0×1.5 cm. Scintigraphy with 99 mTc-Tectrotyd followed by SPECT-CT showed increased uptake. The patient underwent surgical excision of the mass and histopathological examination confirmed a typical thymic carcinoid. Postoperatively, the patient is in complete remission.

Conclusion: 1. ECS can have a rather mild clinical presentation with ACTH levels similar to that of Cushing’s disease and a very favorable response to medical treatment.

2. Ectopic ACTH secretion can appear, although less often, in a cyclic form.

3. Diagnostic approach of ECS can be a real challenge, where repeat testing and perseverance play a significant role.