The ectopic ACTH syndrome

Abstract

Ectopic Cushing's syndrome usually relates to the ectopic ACTH syndrome (EAS) and represents ∼20% of ACTH-dependent and ∼10% of all types of Cushing's syndrome (CS). Nearly any neuroendocrine or non-endocrine tumours may be associated with EAS, but the more prevalent tumours are bronchial carcinoids, small cell lung carcinomas, pancreatic carcinoids, thymic carcinoids, medullary carcinomas of the thyroid, and phaeochromocytomas. Occult tumours are highly represented in all the series (12-38%) and constitute the more challenging cases of EAS, requiring long term follow-up. The lack of any completely reliable diagnostic test procedure and imaging to clearly reveal the source of EAS suggests that we should adopt a step-by-step multidisciplinary approach for their diagnosis and therapeutic management. Clinical features are often similar in ACTH-dependent CS, but the rapid onset and progress may suggest an ectopic source. A combination of biochemical tests and imaging studies seems the most appropriate approach for the prompt identification of EAS, even if there are several pitfalls to be avoided along the way. The most appropriate management for cure of EAS, when its source is identified, is surgical excision after controlling the hypercortisolaemia by inhibitors of cortisol secretion and other newer modalities alone or in combination; bilateral adrenalectomy remains an alternative option. Tumour histology, the presence of metastases and the effective control of hypercortisolaemia affect mortality and morbidity. If a source repeatedly fails to be found, the prognosis is often favourable but the identification of a malignant tumour should still be sought during life-long follow-up to avoid the calamity of misdiagnosis.

Metastatic Pancreatic Neuroendocrine Tumor with Ectopic Adrenocorticotropic Hormone Production

“…Primary sites include the lung (bronchial carcinoids or small cell carcinomas), but can more rarely include the pancreas, thymus, gastrointestinal tract, and prostate (1,10). In our case, MRI detected a pancreatic head mass, not seen on initial CT imaging.…”

“…Resection of the primary tumor can be performed, but reported surgical success has been only modest (30%-50%) (1). Limited experiences support the safety and effi cacy of early bilateral adrenalectomy in refractory cases (14).…”

“…Ultimately, the patient underwent bilateral adrenalectomy, but died within 4 months of symptom onset secondary to postoperative complications. E ctopic adrenocorticotropic hormone (ACTH) production outside the pituitary gland occurs in approximately 10% of patients presenting with Cushing's syndrome (1). Pancreatic neuroendocrine tumors (NET) are a rare cause of ectopic ACTH syndrome.…”

Ectopic Cushing syndrome in small cell lung cancer: A case report and literature review

“…Complete imaging examination, related blood and urine tests, low dose and high dose dexamethasone tests, immunohistochemical characteristics, and cell proliferation potential (Ki‐67) should be considered when suspicious of ECS. If a lesion cannot be located on CECT, then ostroscan will also not be effective for detection 3, 11…”

Recommendations of the Neuroendocrinology Department of the Brazilian Society of Endocrinology and Metabolism for the diagnosis of Cushing’s disease in Brazil

“…Somatostatin receptor scintigraphy with Indium ( (172), although its sensitivity is not higher than that of plain images (170,173,174), mainly due to the typically small size of bronchial carcinoid tumors (175).…”