Ectopic Cushing syndrome resolved by thoracoscopic resection of carcinoid tumour of thymus: A study

Ectopic Cushing syndrome (ECS) is a sporadic condition. Even uncommon is an ECS that derives from a carcinoid tumour of the thymus. These tumours may pose several diagnostic and therapeutic conundrums. This report discusses the differential diagnosis, clinicopathological findings, and effective treatment of a rare case of ECS using a minimally invasive approach.

A 29-year-old woman with Cushing syndrome presented with facial flushing. Physical examination revealed hypertension (blood pressure: 141/100 mmHg). A mediastinal tumour was discovered to be the cause of the patient's chronic hypokalemia and hypercortisolemia. Cortisol levels increased in the morning, reaching 47.7 ug/dL. The levels of the hormones ACTH, aldosterone, and renin were determined to be 281 pg/mL, 3.0 ng/dL, and 2.1 pg/mL, respectively. The presence of hypertension, hypokalemia, and alkalinity suggested Cushing's syndrome, which was proven to be ACTH-dependent ECS by a dexamethasone suppression test. A chest CT scan revealed inflammation in the posterior basal region of the right lower lobe. The superior anterior mediastinum was characterized by round-shaped isodensity lesions with distinct borders. She underwent thoracoscopic anterior mediastinal tumour excision via the subxiphoid technique (R0 resection); following surgery, her blood pressure returned to normal, and the hypernatremia/hypopotassemia resolved. The tumour was determined to be a thymic carcinoid. Most notably, cortisol levels fell to half of their presurgical levels after one hour of surgery, and other abnormalities were corrected substantially postoperatively.

Thoracoscopic excision of thymic tumours by subxiphoid incision may be a useful treatment option for ECS caused by neuroendocrine tumours of the thymus

Reference:

Zhou, Z., Chai, W., Yang, L. et al. Successful resolution of ectopic Cushing syndrome by minimally invasive thoracoscopic resection of the neuroendocrine tumor of the thymus: a rare case report. BMC Surg 22, 226 (2022). https://doi.org/10.1186/s12893-022-01674-0