Image in endocrinology: Localization of an occult adrenocorticotropin-secreting carcinoid tumor with somatostatin receptor scintigraphy using single-photon emission computed tomography/computed tomographic image scanning

[Surgical treatment of ACTH-ectopic syndrome]

ACTH-ectopic syndrome is a severe, multiple-symptom disease characterized by secretion of adrenocorticotropic hormone (ACTH) by ectopic tumor, increased release of adrenal cortical hormones and clinical picture of hypercorticism. Diagnosis and treatment of ACTH-ectopic syndrome is still difficult problem despite the achievements of modern medicine. There are several unresolved issues including optimal diagnostic algorithm, indications for various surgical procedures and their optimal dates. This review is devoted to these questions.

Management of Cushing's syndrome due to ectopic adrenocorticotropin secretion with 1,ortho-1, para'-dichloro-diphenyl-dichloro-ethane: findings in 23 patients from a single center

CONTEXT

Effective treatment for the ectopic ACTH secretion syndrome (EAS) remains a therapeutic challenge. Immediate curative surgery of the responsible nonpituitary tumor is often not possible.

OBJECTIVE

The objective of the study was to evaluate 1,ortho-1, para'-dichloro-diphenyl-dichloro-ethane (O,p'DDD) therapy in EAS.

DESIGN AND PATIENTS

Patients included 36 consecutive patients with EAS from a single center treated between 1990 and 2006. Twenty-three of these patients, including 18 women aged 53.7 +/- 12.9 yr (mean +/- sd), were treated with O,p'DDD. Patient follow-up was 8.04 +/- 9.6 yr.

RESULTS

A mean daily O,p'DDD dose of 3.3 +/- 1.2 g Lysodren equivalent was given for a mean duration of 1.8 +/- 2.1 yr. Urinary cortisol decreased from 2603 +/- 3443 microg/d before treatment to 79 +/- 169 microg/d at the time of maximal O,p'DDD efficacy. Urinary cortisol was normalized in 21 of the 23 patients. Adrenal insufficiency was observed in 20 patients. This was associated with clinical improvement of Cushing's syndrome manifestations, including diabetes, hypertension, and hypokalemia. O,p'DDD plasma levels were 10.4 +/- 6.5 microg/ml in the 12 patients tested at the time of adrenal insufficiency. Side effects were observed during the first 6 months in seven of 15 patients (46%). National Cancer Institute-Classification Common Toxicity Criteria grade 1 or 2 digestive or neurologic toxicity resolved after withdrawal or reduction of O,p'DDD. Careful monitoring was essential to long-term control, clinical improvement, and good tolerability. Medical control of the disease allowed the subsequent characterization of tumors in eight of 13 patients with initially occult tumors.

CONCLUSION

With close monitoring, O,p'DDD could be a potent medical treatment for long-term control and management of EAS.

Approach to the patient with possible Cushing's syndrome

Clinical decision making for patients with suspect hypercortisolism involves a complex diagnostic assessment. Cushing's syndrome remains one of the most challenging endocrine pathologies. Most clinical features overlap with those of common diseases found in the general population, and some patients have an atypical clinical presentation with only isolated symptoms. Recently, several studies have suggested that the prevalence of Cushing's syndrome is higher than previously thought. Therefore, efficient screening tests are needed to identify the few uncovered patients also among unselected high-risk ambulatory patients with disorders potentially related to cortisol excess. The recommended diagnostic tests are 24-h urinary free cortisol, 1-mg overnight dexamethasone suppression test, and late-night salivary cortisol. Once the diagnosis of Cushing's syndrome is established, the next step is the measurement of plasma ACTH. Then, dynamic test and appropriate imaging procedures are the most useful noninvasive investigations for the differential diagnosis. Patients with Cushing's disease are generally responsive to the CRH test and to high-dose glucocorticoid feedback. Bilateral inferior petrosal sinus sampling is considered the gold standard for establishing the origin of ACTH secretion, and it is recommended in patients with ACTH-dependent Cushing's syndrome whose clinical, biochemical, or radiological studies are discordant or equivocal. The present clinical case shows that even if rare, the ectopic ACTH secretion should be considered also in those cases where the pretest probability is low. The management of Cushing's syndrome depends on the exact knowledge of its various causes, paying attention to the many potential diagnostic pitfalls. The choice of test, the modality of specimen collection (blood, urine, and saliva), the quality of measurement (assay methodology and standardization), and close dialogue among endocrinologists, chemical pathologists, and neuroradiologists are key factors for optimal care of patients.