The ectopic adrenocorticotropin syndrome: clinical features, diagnosis, management, and long-term follow-up

CONTEXT

There are few large series of patients with ectopic, nonpituitary, corticotropin (ACTH) secretion (EAS).

OBJECTIVE

The objective of this study was to analyze the clinical, biochemical, and radiological features, management, and treatment outcome of patients with EAS.

DESIGN

This was a retrospective case-record study.

SETTING

The setting for this study was a tertiary referral hospital center.

PATIENTS

Forty patients with EAS were studied.

MAIN OUTCOME MEASURES

Clinical, biochemical, and radiological features and response to therapy and survival were measured.

RESULTS

The median follow-up was 5 yr (range, 2-30 yr). None of the dynamic tests achieved 100% accuracy, but bilateral inferior petrosal sinus sampling showed an absent central gradient in all but one case (one of 12). Imaging correctly identified the lesion at first investigation in 65% of cases. Bronchial carcinoid tumors were the most common cause of EAS (n = 12; 30%), followed by other neuroendocrine tumors (n = 13, 32.5%). In 12.5% of patients, the source of EAS was never found. Octreotide scintigraphy and whole-body venous sampling were of limited value. Surgical attempt at curative resection was successful in 83% (10 of 12) of patients with bronchial carcinoid tumors; others responded generally well to adrenolytic therapy or bilateral adrenalectomy. Tumor histology and the presence of distant metastases were the main predictors of overall survival (P < 0.05).

CONCLUSIONS

A variety of tests and imaging studies are necessary for the correct diagnosis of the EAS, but even then, up to 20% of cases present a covert or occult EAS syndrome. These cases require a prolonged follow-up, review, and repetition of diagnostic tests and scans.

Neuroendocrine carcinoma (carcinoid) of the thymus associated with Cushing's syndrome

Neuroendocrine carcinoma (carcinoid) of the thymus associated with Cushing's syndrome is a rare disease. Recent evidence suggests that these tumors form part of a continuous spectrum ranging from well-differentiated carcinomas to small cell carcinomas. We report two new cases and review the 23 cases reported in the literature since 1972. The different diagnostic modalities are discussed, and an algorithm for the diagnosis of ectopic secretion of adrenocorticotropin (ACTH) is presented. In the future, the advent of radiologic and nuclear imaging as well as more accurate workup should help to diagnose these tumors at an earlier stage and improve the long-term outcome.

Ectopic adrenocorticotropin production: disappearance after removal of inflammatory tissue

A patient presented with the clinical and laboratory features of the ectopic ACTH syndrome. No ACTH-producing tumor was found, and bilateral adrenalectomy was performed to correct the hypercortisolism. Six months later, the removal of a pseudotumor containing only fat and inflammatory tissue resulted in normalization of both basal plasma ACTH levels and the ACTH feedback response to cortisol infusion. It is suggested that the leukocytes in the inflammatory tissue were the source of the ectopic ACTH production.

Immunocytochemical study of 18 tumours causing ectopic Cushing's syndrome

Eighteen cases of Cushing's syndrome caused by ectopic production of peptide hormones were investigated by histological and immunocytochemical methods and the findings correlated with clinical and biochemical observations. Immunocytochemistry showed immunoreactive adrenocorticotrophic hormone (ACTH) or peptides derived from the ACTH precursor (pro-opiomelanocortin (POMC], or both, in a total of 10 cases: five of these also contained immunoreactive-alpha-melanocyte stimulating hormone, indicating more extensive translational processing of POMC than normally occurs in healthy corticotrophs of the anterior pituitary; in two further cases peptides capable of stimulating ACTH release from the anterior pituitary were present. In the remaining six cases immunocytochemistry failed to show the presence of ACTH, other POMC derived peptides, or peptides with ACTH releasing properties. These findings correlate well with the histological and clinical observations, in that the six tumours had been clinically overt, caused rapid death, and histologically seemed to be highly malignant. In contrast, the 12 other tumours were occult to radiological examination, patients had a much improved survival rate, and histologically the tumours seemed to be less aggressive. All but one of the tumours in this series showed a degree of neuroendocrine differentiation, indicated by the presence of neuron specific enolase. These results suggest that one feature of highly malignant tumours, which cause an ectopic endocrine syndrome, is a high secretion of peptide hormones, leaving amounts that are too small to be shown by immunocytochemistry.

MRI appearances of an ectopic pituitary adenoma: case report and review of the literature

MR images of an ectopic pituitary adenoma have been published in only a single case, a suprasellar mass. We present a patient with Cushing's disease in whom MRI revealed a pituitary adenoma within the sphenoid sinus. Radiologic characteristics of ectopic pituitary adenomas are reviewed, with emphasis on MRI, which demonstrates a soft tissue mass, isointense with gray matter on T1-weighted images, which enhances in a heterogeneous manner.

Ectopic ACTH syndrome: molecular bases and clinical heterogeneity

There are roughly two types of ectopic ACTH syndrome (EAS). one associated with overt malignancies and one with occult neoplasms. The prototype of the first condition is Cushing's syndrome sustained by small-cell lung cancer (SCLC), while bronchial carcinoid tumors are the most common occult sources of ACTH. Patients with EAS and SCLC may have an atypical presentation with muscle wasting and weight loss that are more frequently observed than the classic cushingoid features. These patients have a poor prognosis because SCLC associated with the EAS is more resistant to chemotherapy and the severe hypercortisolism is responsible for a high rate of life-threatening complications during treatment. Conversely, the clinical and biochemical features of the EAS associated with carcinoid may overlap those seen in pituitary-dependent Cushing's syndrome. An extensive radiological and hormonal work-up is necessary to detect the extrapituitary source of ACTH. However, the differentiation between the pituitary, or eutopic, from the non-pituitary, or ectopic, source of ACTH secretion may be extremely difficult in some cases despite the wide diagnostic armamentarium available. Molecular biology studies have demonstrated that the carcinoid cells achieve a process of corticotroph differentiation being able to express the proopiomelanocortin (POMC) gene and to process POMC correctly to release large amounts of intact ACTH. Conversely, SCLC processes POMC in an aberrant way releasing high concentrations of ACTH precursors and less intact ACTH in the circulation.

The cellular and molecular basis of the ectopic ACTH syndrome

In recent years the techniques of molecular and cellular biology have made it possible to begin to dissect the origins and behaviour of the ACTH-secreting tumour cell. It is becoming apparent that these tumours represent undifferentiated neuroendocrine cells, and it may be that their peptide-secreting properties may have no more sinister oncological significance. However, an autocrine role for beta-endorphin may confer a selective growth advantage on the POMC-expressing cell. It is still not clear why glucocorticoids fail to inhibit the POMC gene in these extra-pituitary tumours despite the presence of glucocorticoid receptors. This may not be resolved until the mechanism for inhibition of POMC by glucocorticoids in the normal pituitary is understood, although it is tempting to speculate that a mutation in the glucocorticoid receptor or a tissue specific interaction is responsible for the resistance of POMC observed in the ectopic ACTH syndrome. In studying the peptides secreted by the extra-pituitary tumours responsible for the ectopic ACTH syndrome it would appear that direct measurement of ACTH precursors and comparison with the circulating concentrations of ACTH can give valuable information on the percentage of tumours which do not effectively process the ACTH precursors. However, far more data have to be collected on patients with occult tumours in order to identify whether this type of processing is tissue specific. Nevertheless, these studies provide useful insights into the mechanisms of intracellular signalling and regulation in such tumours which may identify unique pharmacological tools to inhibit ACTH secretion or more importantly tumour growth.

Role of surgery in management of adrenocorticotropic hormone-producing islet cell tumors of the pancreas

BACKGROUND

Ectopic adrenocorticotropic hormone-producing islet cell tumors of the pancreas (ACTH-ICT) are a rare cause of Cushing's syndrome with a severe and rapidly progressive clinical course.

METHODS

Charts were reviewed on all patients evaluated and treated for proven Cushing's syndrome caused by ACTH-ICT (n = 12), specifically for the role of surgery in the management of this disease.

RESULTS

Ten (83%) of twelve patients with ACTH-ICT had liver metastases at the time of diagnosis (eight of eight with Zollinger-Ellison syndrome, two of four without Zollinger-Ellison syndrome). Surgical management of the primary tumor included three patients who underwent distal pancreatectomy combined with hepatic resection and one patient who underwent laparoscopic enucleation of a tumor from the pancreatic tail. Eight of twelve patients underwent bilateral adrenalectomy to control symptoms of Cushing's syndrome, including three patients who underwent concurrent distal pancreatectomy and hepatic resection. Six of twelve patients died of the disease within 2 1/2 years of diagnosis, four are alive with progressive hepatic metastases, and one has biochemical evidence of disease.

CONCLUSIONS

ACTH-ICT of the pancreas is an aggressive tumor, particularly when there is coproduction of gastrin. The benefit of aggressive surgical resection of primary or metastatic ACTH-ICT has not been established. However, palliative bilateral adrenalectomy is justified, because no patients had biochemical cures after aggressive surgical resection in this series.

Mini-review: pheochromocytomas causing the ectopic ACTH syndrome

Cushing's syndrome (CS) is a condition associated with high cortisol levels and affects around 0.7-2.4 cases per million population per year [1-3]. Approximately 80 % of cases of CS are secondary to excess adrenocorticotrophin (ACTH) secretion, while in around 20 % the primary abnormality lies in the adrenal, most often an adrenal adenoma or carcinoma. Of the ACTH-dependent causes, some 80-90 % are due to a pituitary adenoma-Cushing's disease-but in a significant proportion the cause is ectopic secretion from a non-pituitary source, the ectopic ACTH syndrome (EAS) [4]. The commonest source of ACTH secretion in these patients is a bronchial carcinoid. However, many other tumors are capable of secreting ACTH, and in most series a small but significant number are secondary to an ACTH-secreting pheochromocytoma. Amalgamating the data from 6 large series of patients with ectopic ACTH, pheochromocytoma was the source of ACTH secretion in 19 out of 363 patients (5.2 %) [5-11]. In this mini-review, we present a patient presenting to our department with a pheochromocytoma as well as Cushing's syndrome due to ectopic ACTH secretion by the pheochromocytoma, and we discuss published cases in the world literature to assess its significance. We emphasize the problems in the simultaneous management of these two serious endocrine conditions.

Corticotroph cell pituitary adenoma within an ovarian teratoma. A new cause of Cushing's syndrome

A 24-year-old woman with severe Cushing's syndrome was found to have corticotroph cell pituitary adenoma arising within a benign cystic ovarian teratoma. The patient manifested sustained hypercortisolemia and lack of suppression of either adrenocorticotropin (ACTH) or cortisol production. There was no evidence of a pituitary mass or secretion of other hormones. After careful clinical evaluation, no other tumor masses were found. Resection of the ovarian tumor led to normalization of ACTH and cortisol levels. Densely granulated corticotroph tumor cells with prominent Type I microfilaments and intracytoplasmic ACTH immunoreactivity characterized the neoplasm as a pituitary corticotroph cell adenoma. This is, to our knowledge, the first case reported of a functioning pituitary adenoma arising within a benign cystic teratoma.

Clinical utility of plasma POMC and AgRP measurements in the differential diagnosis of ACTH-dependent Cushing's syndrome

CONTEXT

Distinguishing between pituitary [Cushing's disease (CD)] and ectopic causes [ectopic ACTH syndrome (EAS)] of ACTH-dependent Cushing's syndrome can be challenging. Inferior petrosal sinus sampling (IPSS) best discriminates between CD and occult EAS but is a specialized procedure that is not widely available. Identifying adjunctive diagnostic tests may prove useful. In EAS, abnormal processing of the ACTH precursor proopiomelanocortin (POMC) and the accumulation of POMC-derived peptides might be expected and abnormal levels of other neuropeptides may be detected.

OBJECTIVE

The objective of the study was to evaluate the diagnostic utility of POMC measurements for distinguishing between CD and occult EAS in patients referred for IPSS. Another objective of the study was to evaluate in parallel the diagnostic utility of another neuropeptide, agouti-related protein (AgRP), because we have observed a 10-fold elevation of AgRP in plasma in a patient with EAS from small-cell lung cancer.

DESIGN AND PARTICIPANTS

Plasma POMC and AgRP were measured in 38 Cushing's syndrome patients presenting for IPSS, with either no pituitary lesion or a microadenoma on magnetic resonance imaging, and in 38 healthy controls.

RESULTS

Twenty-seven of 38 patients had CD; 11 of 38 had EAS. The mean POMC was higher in EAS vs CD [54.5 ± 13.0 (SEM) vs 17.2 ± 1.5 fmol/mL; P < .05]. Mean AgRP was higher in EAS vs CD (280 ± 76 vs 120 ± 16 pg/mL; P = .01). Although there was an overlap in POMC and AgRP levels between the groups, the POMC levels greater than 36 fmol/mL (n = 7) and AgRP levels greater than 280 pg/mL (n = 3) were specific for EAS. When used together, POMC greater than 36 fmol/mL and/or AgRP greater than 280 pg/mL detected 9 of 11 cases of EAS, indicating that elevations in these peptides have a high positive predictive value for occult EAS.

CONCLUSIONS

Expanding upon previous observations of high POMC in EAS, this study specifically demonstrates elevated POMC levels can identify occult ectopic tumors. Elevations in AgRP also favor the diagnosis of EAS, suggesting AgRP should be further evaluated as a potential neuroendocrine tumor marker.

p21-activated kinase 3 is overexpressed in thymic neuroendocrine tumors (carcinoids) with ectopic ACTH syndrome and participates in cell migration

Thymic carcinoid is an important component of the tumor spectrum causing Ectopic ACTH Syndrome (EAS) and usually carries a poor prognosis. Efforts have been focused on exploring the mechanism of the excessive ACTH production in non-pituitary tumors, whereas few studies have reported the molecular events underlying the tumor progression. In this study, seven patients with ACTH producing thymic carcinoids were enrolled. Of note is that five of them showed either lymph node metastasis, local invasion or distant metastasis. By using cDNA profiling approach, we evaluated the expression of cell adhesion pathway genes and found a remarkable overexpression of p21-activated kinase 3 (PAK3) in all thymic carcinoids which was further confirmed at both transcriptional and translational level. RAC1, an upstream activator of PAK3, was also overexpressed in thymic carcinoids. Overexpression of PAK3 in NIH3T3 cell enhanced cell migration and invasion. Importantly, we observed c-Jun NH(2)-terminal kinase (JNK) was activated in PAK3 transfected cells, and inhibition of JNK activity by SP600125, a JNK pathway inhibitor, abolished PAK3 mediated cell migration. Activation of JNK pathway was also detected in thymic carcinoid with high level of PAK3 expression. Our findings suggested a potential role of PAK3 in the progression of ACTH-producing thymic carcinoid.

Work-up and management of paediatric Cushing's syndrome

PURPOSE OF REVIEW

Paediatric Cushing's syndrome presents a diagnostic and therapeutic challenge. Most paediatric endocrinologists have limited experience in managing children or adolescents with Cushing's syndrome and thus benefit from close consultation with adult colleagues. A protocol for investigation of the child with suspected Cushing's syndrome is presented followed by principles of management.

RECENT FINDINGS

Cushing's syndrome is rare in childhood, but causes serious morbidity. Investigations have evolved and now include new genetic and imaging techniques as well as classical endocrine studies. In Cushing's disease trans-sphenoidal surgery has transformed management, although only a few surgeons have experience in children. Pituitary radiotherapy is effective second-line therapy.

SUMMARY

Early diagnosis and treatment of Cushing's syndrome is vital for long-term outcome. The overall prognosis for Cushing's syndrome is good but challenges remain to ensure normal postcure growth and body composition.

Cushing's syndrome associated with a nested stromal epithelial tumor of the liver: hormonal, immunohistochemical, and molecular studies

CONTEXT

Ectopic ACTH syndrome (EAS) is principally associated with aggressive malignant tumors but also with neuroendocrine tumors of good prognosis. Recently, rare nonhepatocytic nested stromal and epithelial tumors (NSET) were characterized by their possible association with Cushing's syndrome of which biochemical and physiopathological features were still incompletely studied.

OBJECTIVE

To describe the clinical and hormonal characteristics of an EAS originating from a liver NSET and further understand the mechanism of cortisol overproduction.

DESIGN AND SETTING

This is a clinical case report from the Endocrinology Department of Caen University Hospital, France.

PATIENT AND INTERVENTION

A 17-year-old female patient was found to have a large liver NSET with mild Cushingoid clinical features and intense biological hypercortisolism but moderate ACTH secretion. Resection of the tumor was curative with a 30-month follow-up.

RESULTS

The epithelial component of the tumor coexpressed ACTH mildly, corticotropin-releasing hormone (CRH) strongly, and 11beta-hydroxysteroid dehydrogenase at a level comparable with normal human hepatocytes.

CONCLUSIONS

Liver NSET is a new cause of EAS, which may evoke hypercortisolism by multiple biochemical pathways.

An ectopic, ACTH producing, oncocytic carcinoid tumor of the thymus: report of a case

A 39-year-old man with an ACTH producing oncocytic carcinoid of the thymus is reported here. His symptoms were pigmentation, facial and pretibial edema, and high blood pressure. Endocrinological examination revealed the ectopic ACTH syndrome and, especially, high content in the intrathoracic venous blood. On histological examination, the tumor was found to be composed of uniform eosinophilic cells, with no argentaffin granules being demonstrated. Ultrastructural findings revealed a large number of mitochondria and numerous distinct electron-dense neurosecretory granules in the cytoplasm. Abnormally high levels of ACTH, beta-endorphin and gamma-MSH were also found in this tumor tissue. By total extirpation of the tumor, clinical symptoms and laboratory data were entirely normalized.

Suprasellar adrenocorticotropic hormone-secreting ectopic pituitary adenoma: case report and literature Review

OBJECTIVE AND IMPORTANCE

Functional ectopic pituitary adenomas are rare and can be misdiagnosed as extensions of pituitary adenomas when they are located in the vicinity of the normal gland. In this report, we present a case of an ectopic adrenocorticotropic hormone-secreting suprasellar pituitary adenoma that caused Cushing's disease. A literature review of previously reported ectopic pituitary adenomas is included to illustrate the diverse clinical manifestations of this disease entity.

CLINICAL PRESENTATION

An 11-year-old boy was noted to have hirsutism, a buffalo hump, and unexplained weight gain consistent with Cushing's syndrome. Laboratory investigations revealed that the boy had elevated adrenocorticotropic hormone and serum cortisol levels unsuppressed by dexamethasone. Magnetic resonance imaging scans were suggestive of a pituitary adenoma with suprasellar extension.

INTERVENTION

The initial transsphenoidal approach failed to achieve complete surgical resection. A repeat operation in which the pterional approach was used revealed a suprasellar pituitary adenoma without association with intrasellar contents. The patient's cushingoid symptoms improved significantly 3 months after surgery.

CONCLUSION

Ectopic pituitary adenomas should be considered in the differential diagnosis for all patients with Cushing's syndrome. Furthermore, surgical approaches should be chosen carefully once the diagnosis of ectopic pituitary adenoma is made.

Ectopic corticotroph adenoma in the cavernous sinus: case report

OBJECTIVE AND IMPORTANCE

Adrenocorticotropin (ACTH)-secreting pituitary adenomas causing Cushing's disease are often difficult to identify because of their variable locations and their small size. This report presents histological evidence of an ectopic ACTH-secreting adenoma located entirely within the cavernous sinus.

CLINICAL PRESENTATION

A 62-year-old woman presented with central obesity, hypertension, and osteoporosis. Endocrinological evaluation suggested the presence of an ACTH-secreting pituitary adenoma; however, imaging studies, including dynamic magnetic resonance imaging, did not reveal any visible lesions in the pituitary gland. Bilateral cavernous sinus sampling demonstrated a large central/peripheral ACTH gradient, with a right/left ACTH gradient. The patient was treated as having pituitary-dependent Cushing's disease, until she died suddenly as a result of acute respiratory failure.

INTERVENTION

In a postmortem histological examination, an ACTH-secreting adenoma was found in the right cavernous sinus, which was completely surrounded by dura mater and had no direct connection with the pituitary gland.

CONCLUSION

Although they are rare, such adenomas located in the cavernous sinus should be recognized as one of the reasons for inaccurate cavernous sinus sampling and the failure of transsphenoidal surgery for patients with ACTH-dependent Cushing's syndrome.

Corticotropin-releasing hormone test: improvement of the diagnostic accuracy of simultaneous and bilateral inferior petrosal sinus sampling in patients with Cushing syndrome

Twenty-six consecutive patients with ACTH-dependent Cushing syndrome were subjected to simultaneous, bilateral inferior petrosal sinus sampling for ACTH assay before and after ACTH-releasing hormone (CRH) stimulation. The baseline ACTH inferior petrosal sinus/periphery (IPS/P) ratio was > or = 2 in 12 of 26 patients (46%), whereas the CRH-stimulated IPS/P ratio was > or = 3 in 19 of 26 patients (73%). A pituitary adenoma, ACTH-secreting at immunostaining, was surgically proved in all of the 19 patients who had an ACTH IPS/P ratio > or = 2 basally or > or = 3 after the CRH test but also in three other patients who did not have such ratios. The value of the basal IPS/P ratio and the complete lack of ACTH increase after CRH led to the diagnosis of an ectopic ACTH syndrome in four patients: a bronchial carcinoid was found in three patients, and the site of the tumor was still unknown in the other. In conclusion, the CRH test improved the diagnostic accuracy of inferior petrosal sinus sampling from 61.5% (12 pituitary, 4 ectopic) to 92.0% (19 pituitary, 4 ectopic). Thus it should be performed during the diagnostic process.

Cushing's syndrome due to ACTH-production of an ovarian carcinoid

The case of a 56-year old woman with severe Cushing's syndrome due to ovarian ACTH-production is described. Both clinical picture and biochemical pattern were consistent with the ectopic ACTH syndrome. ACTH was found by specific immunohistochemical staining in a carcinoid tumor of the patient's right ovary. In contrast, pituitary cells exhibited immunoreactive ACTH to only a minimum extent.

Cushing's syndrome produced by a bronchial carcinoid tumor

A case of bronchial carcinoid tumor with ectopic corticotropin production is described. Cushing's syndrome refractory to therapy, including pituitary irradiation and hypophysectomy, had been present for 12 years before the neoplasm was discovered at autopsy. The tumor was a small nodule localized in the pulmonary parenchyma and an adjacent hilar lymph node. Corticotropin, serotonin, and neuron-specific enolase were localized in the neoplasm by immunoperoxidase staining.

Ectopic ACTH-secreting pituitary adenomas within the sphenoid sinus

Ectopic pituitary adenomas are defined by the presence of adenomatous pituitary tissue outside the sella and distinctly separate from the pituitary gland. Ectopic ACTH-secreting pituitary adenomas (EAPAs) are a rare cause of Cushing's syndrome. Detecting these radiologically can prove difficult, in part, due to their typically small size and unpredictable anatomical location. In ACTH-dependent Cushing's syndrome, if, despite comprehensive testing, the source of excess ACTH remains occult (including negative work up for ectopic ACTH syndrome) thought should be given to the possibility of the patient harboring an EAPA. In most cases, ectopic ACTH pituitary adenomas within the sphenoid sinus will manifest with symptoms of hormonal excess, have an obvious sphenoid sinus mass on pre-operative imaging and will demonstrate resolution of hypercortisolism after surgical excision if located and removed. Twenty cases of EAPAs have been reported in the literature to date. This paper will review the current literature on all previously reported EAPAs within the sphenoid sinus in addition to the current case.

The Clinical Features and Molecular Mechanisms of ACTH-secreting Pancreatic Neuroendocrine Tumors

OBJECTIVE

Pancreatic neuroendocrine tumors (pNETs) causing ectopic adrenal corticotropic hormone (ACTH) syndrome (EAS) are rare and aggressive with little known information. We aimed to elucidate the clinical features and molecular mechanisms of pNETs with EAS by methylation analysis.

METHODS

Seven patients with ectopic ACTH-secreting pNETs who were diagnosed at Shanghai Clinical Endocrine and Metabolic Diseases Center and Pancreatic Disease Center in Ruijin Hospital between 2001 and 2019 were enrolled. Twenty patients with ectopic ACTH-secreting thymic neuroendocrine tumors (TNETs) and 7 with nonfunctional pNETs (nf-pNETs) were also enrolled as controls. We collected clinical data and measured POMC promoter CpG methylation.

RESULTS

All 7 patients had elevated ACTH and urinary free cortisol (UFC) levels with positive ACTH staining in the pancreas and were diagnosed with ectopic ACTH-secreting pNET. Of the 7 patients, 6 underwent surgery and 1 underwent transarterial embolization (TAE). Two patients were free of disease after surgery; 2 died within 90 days after surgery; and 3 had metastases and died within 1 year. Compared with ACTH-secreting TNETs, ACTH-secreting pNETs had similar clinical and biochemical features but a significantly poorer prognosis. POMC promoter CpG methylation was significantly lower in ACTH-secreting pNETs than in nf-pNETs and normal pancreas.

CONCLUSIONS

ACTH-secreting pNETs are aggressive and fatal. Surgery is definitively curative for patients with resectable primary tumors without metastasis. Pro-opiomelanocortin (POMC) promoter hypomethylation caused pNETs to produce ACTH. This study further supplements the genetic features of ACTH-secreting NETs.

[ACTH-producing paraganglioma of the paranasal sinuses]

Paragangliomas are tumours of neuroectodermal origin and hormonally active in rare instances. They are very unusual in the paranasal sinuses. We report on the first case--as far as we know--of a recurrent nasal paraganglioma, which started to produce ACTH after a period of ten years and resulted in Cushing's syndrome. Resection of the tumour normalised ACTH and cortisol secretion.

Cushing's syndrome secondary to ectopic ACTH secretion from a primary ovarian carcinoma

We report a 63-year-old woman who presented with clinical and biochemical features of ACTH dependent Cushing's syndrome secondary to a primary ovarian carcinoma. The tumour produced very high levels of ACTH precursors, consistent with defective POMC processing.