Paraneoplastic Cushing syndrome, case-series and review of the literature

Diagnostic performance of various imaging modalities in localizing ectopic ACTH syndrome: A systematic review

BACKGROUND

To elucidate the role of various imaging modalities for tumor localization in ectopic ACTH Cushing's syndrome (EAS).

DESIGN AND METHOD

Systematic review of the literature published between January 2015-2024 was performed. Patients (290 EAS patients, 23.8% Occult) who underwent contrast enhanced CT (CECT) and at least one PET/CT-scan (68Ga-SSTR, FDG and/or F-DOPA) were included.

RESULTS

The sensitivity for identifying EAS tumor was comparable across CECT (63.1%, n=290), SSTR-PET/CT (58.2%, n=187), and FDG-PET/CT (57.6%, n=191), but was poor for DOPA-PET/CT (30.8%, n=26). Sensitivity for detecting metastasis was also comparable across CECT (78%, n=73), SSTR-PET/CT (85.3%, n=41), and FDG-PET (73.7%, n=38). For localised lesions, sensitivity as per etiology and grade of NET were similar for three scans, with exception of Thymic NET and grade 1 NET where CECT was better than FDG PET/CT. In patients not localised on CECT, sensitivity of SSTR PET/CT was 33.3% (vs. 18.9% FDG-PET/CT) whereas for patients negative on CECT and FDG-PET, sensitivity of SSTR-PET/CT was 15%. In cases where CECT and SSTR-PET/CT failed to localize, the sensitivities of FDG-PET/CT and DOPA-PET/CT were only 5.7% (2/35) and 0% (0/9), respectively. SSTR-PET/CT has a distinct advantage with significantly lesser false positive (FP) lesions (2.6%, mostly in thyroid/or pancreas). In comparison, CECT and FDG-PET/CT had FP ∼11% (mostly in lung and/or mediastinum), most of which were negative on SSTR-PET/CT.

CONCLUSIONS

As per the current evidence, SSTR-PET/CT can be considered as the scan of choice in EAS evaluation, and further research is needed as one-fourth of the lesions remain occult.

Management of small cell lung cancer complicated with paraneoplastic Cushing's syndrome: a systematic literature review

Paraneoplastic Cushing's syndrome (PCS) is a rare, but clinically important feature of small cell lung cancer (SCLC) that is associated with even worse prognosis. To identify key considerations in comprehensive management of SCLC patients complicated with PCS, we conducted a systematic review of relevant reports on PubMed and Web of Science, focusing on SCLC with PCS cases. The systematic review analyzed 61 reports published between 1985 and 2022 with a total of 157 SCLC patients included. Out of the 157 patients, 132 (84.1%) patients across 58 (95.1%) reports were diagnosed with ectopic Cushing's syndrome. The immunohistochemical (IHC) staining for adrenocorticotropic hormone (ACTH) was performed on 30 (19.1%) patients across 22 (36.1%) reports and demonstrated encouraging performance. For treatment, chemotherapy and ketoconazole were utilized in 50 (81.97%) and 24 (39.34%) reports, respectively. Regarding cause of death, infection and cancer were equally frequent, each being recorded in 17 (27.87%) reports. To conclude, the majority of PCS cases in SCLC patients were caused by ectopic hormone secretion. In order to make a differential diagnosis, it is recommended to utilize IHC staining for a specific hormone such as ACTH or corticotropin-releasing hormone. In the comprehensive treatment of SCLC with PCS patients, effective management of hypercortisolism and potent safeguarding against infection play two crucial roles. Ultimately, further confirmations are required regarding the specificity and accuracy of IHC staining technique as well as the efficacy and safety of immunotherapy in the treatment of SCLC with PCS patients.

Continuing Challenges in the Definitive Diagnosis of Cushing's Disease: A Structured Review Focusing on Molecular Imaging and a Proposal for Diagnostic Work-Up

The definitive diagnosis of Cushing's disease (CD) in the presence of pituitary microadenoma remains a continuous challenge. Novel available pituitary imaging techniques are emerging. This study aimed to provide a structured analysis of the diagnostic accuracy as well as the clinical use of molecular imaging in patients with ACTH-dependent Cushing's syndrome (CS). We also discuss the role of multidisciplinary counseling in decision making. Additionally, we propose a complementary diagnostic algorithm for both de novo and recurrent or persistent CD. A structured literature search was conducted and two illustrative CD cases discussed at our Pituitary Center are presented. A total of 14 CD (n = 201) and 30 ectopic CS (n = 301) articles were included. MRI was negative or inconclusive in a quarter of CD patients. ¹¹C-Met showed higher pituitary adenoma detection than ¹⁸F-FDG PET-CT (87% versus 49%). Up to 100% detection rates were found for ¹⁸F-FET, ⁶⁸Ga-DOTA-TATE, and ⁶⁸Ga-DOTA-CRH, but were based on single studies. The use of molecular imaging modalities in the detection of pituitary microadenoma in ACTH-dependent CS is of added and complementary value, serving as one of the available tools in the diagnostic work-up. In selected CD cases, it seems justified to even refrain from IPSS.

Ectopic Cushing's Syndrome Secondary to Acinic Cell Carcinoma of the Parotid Gland: A Case Report

We present a case report of a patient with a rare high-grade transformation of an acinic cell carcinoma (ACC) of the parotid gland, who developed Cushing's syndrome (CS) as a result of ectopic secretion of adrenocorticotropic hormone by the tumour. The hypercortisolism was successfully treated with metyrapone, and the ACC was treated with local radiotherapy and a combined six cycles of gemcitabine and cisplatin, having achieved a partial response to the tumour. A multidisciplinary approach and combined medical treatment with radiotherapy and were essential for disease control and CS management. ACC should be considered in the differential diagnosis of ectopic CS.

[Arterial hypertension of infrequent cause]

Arterial hypertension is generally classified as primary or essential (90%), and secondary (10%). Infrequent causes of the latter include Cushing's syndrome, classified as ACTH-dependent and independent. A small percentage of ACTH-independent cases are due to ectopic ACTH secretion, generally due to neoplasia, and can present as arterial hypertension and hyperglycaemia that are refractory to pharmacological measures, metabolic alkalosis and hypokalaemia that are difficult to control, but which help guide the initial diagnosis. We present two clinical cases with a diagnosis of ectopic ACTH secretion secondary to small cell lung carcinoma, in which one of the debut manifestations was unknown, difficult to control arterial hypertension.

Inferior petrosal sinus sampling and stimulation with CRH: 15 years of experience in a tertiary hospital

BACKGROUND

Inferior petrosal sinus sampling (IPSS) is indicated in the diagnosis of adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome (CS), especially when the results of the initial diagnostic tests are discordant.

OBJECTIVE

To describe the patients who underwent this invasive functional test in a tertiary hospital.

METHODS

This was an observational study of a retrospective cohort of patients with ACTH-dependent CS and IPSS between 2004 and 2019. We determined their epidemiological, hormonal, radiological and functional characteristics, and evaluated their diagnostic capacity and optimal cut-off points to differentiate between Cushing's disease (CD) and ectopic Cushing's syndrome (ECS).

RESULTS

23 patients were evaluated, of which 65.2% were women with the average age of 42 (36-62) years. ACTH secretion of pituitary origin was evident in 82.6% of the patients and of ectopic origin in 17.4%. Plasma cortisol, urinary free cortisol, and ACTH levels were higher in patients with ECS. Regarding IPSS, the baseline central/peripheral ACTH gradient detected 89.5% of patients with CD and after stimulation with CRH, 100%. The optimal cut-off points in the diagnosis of CD were 2.06 at baseline and 2.49 after CRH stimulation.

CONCLUSION

IPSS with CRH stimulation is a test with a high diagnostic accuracy for correctly classifying patients with CD and ECS. The cut-off points of the gradients may be different from the classic ones. Therefore, we recommend that each center perform its own evaluation.

Differences in outcomes of bilateral adrenalectomy in patients with ectopic ACTH producing tumor of known and unknown origin

BACKGROUND

Endogenous Cushing syndrome (CS) can be caused by ectopic corticotropin-producing tumors of known (EK) and unknown origin (EU). Bilateral adrenalectomy (BA) can be used as definite treatment of hypercortisolism in such cases. This study compared patients undergoing BA for CS secondary to EK vs EU.

METHODS

Retrospective review (1995-2017) of patients undergoing BA due to EK or EU. We analyzed demographic characteristics, laboratory values, intraoperative variables, surgical outcomes, and survival.

RESULTS

48 patients (26 EU, 22 EK) were identified. Serum cortisol and ACTH concentrations were similar. 92% of BA for EU were performed minimally invasively vs 77% for EK, P = 0.22. Complications occurred in 19% of EU and 4.5% EK, P = 0.2. Mean survival was 4.3 years for EU and 4.0 years for EK without difference in all-cause mortality P = 0.63.

CONCLUSION

BA cure rate was 100% for CS in EU and EK. Morbidity, long term and all-cause mortality differences were not statistically significant between EK and EU.

Ectopic ACTH Secretion in a Child With Metastatic Ewing's Sarcoma: A Case Report

Ectopic ACTH syndrome is rare in pediatric age. Sarcomas that cause Ectopic ACTH Syndrome (EAS) are even more uncommon. Currently, only three cases of EAS caused by Ewing' sarcoma have been reported. We detail a 10-year-old boy with Cushing's syndrome symptoms caused by ectopic ACTH production by a metastatic Ewing's sarcoma of the right ischio-pubic and ileo-pubic branches. The rapid appearance of cushingoid symptoms, with significant weight gain, acne, hirsutism, and hypercortisolism were implications of ectopic ACTH production as paraneoplastic Cushing's Syndrome. The very high levels of ACTH and non-suppression at the high dose dexamethasone test confirmed the clinical suspicion. We underline the possibility EAS was caused by an ACTH-secreting tumor, including soft tissue sarcomas.

Ectopic Cushing's Syndrome Unveiling a Metastatic Parotid Carcinoma

Introduction

Adrenocorticotropic hormone (ACTH) ectopic production is a rare cause of Cushing syndrome (CS). The most commonly associated tumours are small-cell lung carcinoma along with bronchial and thymic carcinoids. To date, only 5 cases have been published in the literature featuring ectopic ACTH secretion from metastatic acinic cell carcinoma (ACC) of the parotid gland. We hereby describe a very uncommon case of ectopic CS (ECS) unveiling a metastatic parotid ACC.

Case Presentation

A 46-year-old man with hypertension and dyslipidemia diagnosed 4-months before, as well as new-onset diabetes mellitus unveiled 1-month earlier, was referred to emergency department for hypokalemia. Hormonal study and dynamic biochemical tests performed indicated ECS. Imaging and cytological findings pointed toward a likely primary right parotid malignancy with liver metastases. Somatostatin receptor scintigraphy has shown an increased uptake in the parotid gland and mild expression in liver metastasis. The patient underwent right parotidectomy, and histopathologic examination confirmed ACC. Meanwhile, hypercortisolism was managed with metyrapone, ketoconazole, and lanreotide. Despite chemotherapy onset, a rapid disease progression and clinical course deterioration was observed.

Conclusion

The present report highlights a rare ECS, exposing a metastatic parotid ACC, with an aggressive and challenging clinical course, representing the first case whose diagnosis of ECS came prior to ACC.

Diagnostic utility of Gallium-68-somatostatin receptor PET/CT in ectopic ACTH-secreting tumors: a systematic literature review and single-center clinical experience

PURPOSE

Tumors causing ectopic Cushing's syndrome (ECS) are often not visible with conventional imaging. Gallium-68-DOTATATE, DOTATOC, and DOTANOC positron emission tomography/computed tomography (⁶⁸Ga-SSTR PET/CT) reportedly exhibits greater sensitivity in identifying an ECS source, however, evidence is limited to mainly case reports and a few small retrospective studies. Previous systematic ECS imaging review has shown ⁶⁸Ga-SSTR PET/CT sensitivity is similar to CT (81.8%) in histologically-proven cases and is 100% in covert-cases, however, the number of patients was small and no occult cases were reported.

METHODS

We performed a systematic literature review of ⁶⁸Ga-SSTR PET/CT use in ECS patients. We also report 6 consecutive patients with confirmed active and occult ECS who underwent ⁶⁸Ga-DOTATATE PET/CT and were followed at our institution between 2014 and 2019.

RESULTS

We identified 33 articles (23 case-reports, 4 case-series, 5 retrospective studies and 1 prospective study) detailing ⁶⁸Ga-SSTR PET/CT in 69 ECS patients. Overall ⁶⁸Ga-SSTR PET/CT sensitivity was 64.0%, while in histologically confirmed cases (67 lesions), sensitivity was 76.1%. There were two false-positives cases, both in the adrenal glands. In covert cases, ⁶⁸Ga-SSTR PET/CT identified 50% of lesions. There were ten occult cases where all imaging failed to identify an adrenocorticotropic hormone source; source remains unknown. In our case series, ⁶⁸Ga-DOTATATE PET/CT showed decreased uptake in pancreatic neuroendocrine tumor in one patient and did not help identify an ECS source in 5 patients.

CONCLUSION

Both this systematic literature review, the largest to date, and our single- center experience demonstrate a lower than previously reported ⁶⁸Ga-SSTR PET/CT sensitivity for ECS, especially in occult lesions. We suggest that the data on ⁶⁸Ga-SSTR PET/CT in ECS is subject to publication bias, and false-negatives are likely underreported; it's diagnostic value for ECS needs further study.

Ectopic ACTH Syndrome With Association of Multiple Pulmonary Sclerosing Pneumocytomas and Multiple Carcinoid Tumorlets

We present the case of multiple sclerosing pneumocytomas (SPs) associated with ACTH-secreting carcinoid tumorlets responsible for an ectopic Cushing syndrome (ECS). SP is a rare benign tumor originating from pulmonary epithelial cells. An 18-year-old male presented with shortness of breath and right-sided chest pain after exercise. Chest radiograph indicated right pneumothorax and bilateral lung nodules. CT imaging showed innumerable bilateral hypodense pulmonary nodules and a wedge resection gave the definitive diagnosis of SP with associated carcinoid tumorlets. Two years later, he presented with severe back pain in context of thoracic vertebral compression fracture. He had central fat accumulation, violaceous striae, proximal muscle weakness, hypertension, and diabetes. MRI of the pituitary gland showed a 7-mm adenoma. Inferior petrosal sinus sampling with no central-to-periphery gradient suggested an ectopic origin of ACTH, which was confirmed by ACTH expression in a subset of tumorlet cells in the lung lesions. The patient was started on ketoconazole and subsequently underwent a bilateral adrenalectomy. During follow-up, CT scans showed no growth of the lesions, except for the most recent CT scan, in which an increase in the size of the largest nodule was described. Ten years after the diagnosis, the patient remains asymptomatic of his pulmonary lesions. This article provides a case of ECS in the setting of multiple SP with associated carcinoid tumorlets.

Hypokalaemic metabolic alkalosis, hypertension and diabetes: what is the link

Two years after diagnosis of a metastatic neuroendocrine gastrin-secreting tumour and after several cycles of chemotherapy and peptide receptor radionuclide therapy, a 56-year-old woman presented with hypokalaemic metabolic alkalosis, hypertension, leg oedema and new-onset diabetes mellitus. Further investigations revealed renal potassium loss confirmed by a transtubular potassium gradient of 16, fully suppressed serum aldosterone, but instead highly elevated blood levels of morning cortisol and adrenocorticotropic hormone as well as increased urinary excretion of glucocorticoid and mineralocorticoid metabolites. Ruling out other causes, paraneoplastic hypercortisolism was diagnosed. Pharmacological inhibition of the steroid 11β-hydroxylase with metyrapone resulted in complete resolution of metabolic alkalosis, hypokalaemia, hypertension, hyperglycaemia and leg oedema within 1 week.

Hypertension and severe hypokalaemia associated with ectopic ACTH production

Ectopic adrenocorticotropic hormone (ACTH) secretion represents 5%-10% of cases of Cushing's syndrome (CS), and approximately 50%-60% of these arise from neuroendocrine lung tumours, including small-cell lung cancer (SCLC). We report a 42-year-old man admitted with hypertension, metabolic alkalosis and severe hypokalaemia. On physical examination, centripetal obesity with 'moon face' and 'buffalo's hump' were identified, and wheezing on left lung was heard. A markedly elevated serum cortisol, ACTH and urine free cortisol production supported the diagnosis of CS. Chest CT showed a left hilar mass with metastasis to the liver, adrenal glands and lymph nodes. Bronchoscopy identified bronchial infiltration by SCLC. Treatment with metyrapone and chemotherapy was started. Despite initial improvement, progressive clinical deterioration occurred, culminating in death 1 year after diagnosis. Ectopic ACTH secretion is uncommon but should be suspected in patients with severe hypokalaemia, hypertension and metabolic alkalosis, especially in the context of lung cancer.

Case-series of paraneoplastic Cushing syndrome in small-cell lung cancer

The objective of this study is to report three cases of paraneoplastic or ectopic Cushing syndrome, which is a rare phenomenon of the adrenocorticotropic hormone (ACTH)-dependent Cushing syndrome. Three cases are reported in respect of clinical presentation, diagnosis and treatment in addition to relevant literature review. The results showed that ectopic ACTH secretion can be associated with different types of neoplasm most common of which are bronchial carcinoid tumors, which are slow-growing, well-differentiated neoplasms with a favorable prognosis and small-cell lung cancer, which are poorly differentiated tumors with a poor outcome. The latter is present in two out of three cases and in the remaining one, primary tumor could not be localized, representing a small fraction of patients with paraneoplastic Cushing. Diagnosis is established in the setting of high clinical suspicion by documenting an elevated cortisol level, ACTH and doing dexamethasone suppression test. Treatment options include management of the primary tumor by surgery and chemotherapy and treating Cushing syndrome. Prognosis is poor in SCLC. We concluded that in front of a high clinical suspicion, ectopic Cushing syndrome diagnosis should be considered, and identification of the primary tumor is essential.