Cushing's syndrome due to ectopic ACTH production by (neuroendocrine) prostate carcinoma

ACTH-secreting metastatic prostate cancer with neuroendocrine differentiation

Cushing's syndrome (CS) due to ectopic adrenocorticotropic hormone (ACTH) secretion (EAS) can result from a variety of tumours and rarely from those of prostatic origin. We present a male patient in his early 60s with ACTH-secreting metastatic prostate adenocarcinoma with neuroendocrine differentiation (ICD-O code 8574/3) years after prostatectomy and androgen-deprivation therapy, initially presenting with Cushingoid features. After open radical prostatectomy and bilateral orchiectomy for disease recurrence, the patient was found to have metastatic liver and bone lesions highly suggestive of metastatic prostatic cancer. About 10% of cells on liver biopsy expressed ACTH, a finding consistent with EAS as the cause of CS. His stay was complicated with multiple infections and ultimate death. Hence, we report a case of metastatic prostate adenocarcinoma with neuroendocrine differentiation who presented with CS. We also emphasize the importance of adequate and timely treatment.

Comparison of diagnostic efficacy of 18F-FDG PET/CT and 68Ga-DOTANOC PET/CT in ectopic adrenocorticotropic hormone syndrome

PURPOSE

Fluorine-18 (¹⁸F)-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) and gallium-68 (⁶⁸Ga)-somatostatin analog (SSA) PET/CT imaging have been increasingly used in ectopic adrenocorticotropic hormone syndrome (EAS); however, the diagnostic efficacies of these two methods in patients with EAS remain unclear. Our study aimed to compare the diagnostic efficacies of ¹⁸F-FDG PET/CT and ⁶⁸Ga-DOTANOC PET/CT in EAS.

METHODS

The clinical and imaging data of 68 patients with EAS who underwent ¹⁸F-FDG PET/CT and ⁶⁸Ga-DOTANOC PET/CT examinations from December 2016 to April 2021 were analyzed retrospectively, and the diagnostic efficacies of these methods were compared.

RESULTS

In 37 cases, imaging was performed to locate the primary tumor lesion (localization group), and in 31 to evaluate tumor load or metastasis (staging group). Primary tumors were detected in 48.65% (18/37) of the localization group patients. According to scan-based analysis, the tumor lesion detection rates and false positive rates of ¹⁸F-FDG PET/CT imaging and ⁶⁸Ga-DOTANOC PET/CT imaging were 18.92% vs. 45.95% (p < 0.05) and 21.62% vs. 2.70% (p < 0.05) respectively. For lesion-based analysis, the tumor lesion detection rates and false positive rates were 24.13% vs. 58.62% (p >0.05) and 31.04% vs. 3.45% (p < 0.05). In 90.32% (28/31) of the staging group patients, 286 of 292 lesions were confirmed as tumor lesions. Based on scan analysis, the detection rates and false positive rates of ¹⁸F-FDG PET/CT imaging and ⁶⁸Ga-DOTANOC PET/CT imaging were 83.87% vs. 67.74% (p > 0.05) and 12.90% vs. 9.68% (p > 0.05) respectively. Based on lesion analysis, the detection rate and false positive rates were 93.84% vs. 54.80% (p < 0.05) and 1.37% vs. 1.03%(p > 0.05).

CONCLUSION

⁶⁸Ga-DOTANOC PET/CT imaging may be more suitable than ¹⁸F-FDG PET/CT for identifying the primary tumor in patients with EAS, while ¹⁸F-FDG PET/CT may be more advantageous than ⁶⁸Ga-DOTANOC PET/CT for patients with suspected metastasis.

Multiple hormone secretion may indicate worse prognosis in patients with ectopic Cushing's syndrome

PURPOSE

Ectopic Cushing's syndrome (ECS) caused by an ACTH secreting neuroendocrine neoplasm (NEN) is a rare and challenging condition. We aimed to detect predictive and prognostic parameters for ECS patients identified from a retrospective, comprehensive cohort of NENs treated at a tertiary referral center.

METHODS

Medical records of 886 patients with NENs were reviewed. We identified 51 patients with ECS (33 females/18 men); mean age 52 ± 15 years (SD). Clinical parameters including symptoms, biochemical markers, and survival were extracted and further analyzed.

RESULTS

The primary tumor was located in the thorax (n = 28) or pancreas (n = 15) or was of unknown primary origin (n = 8). In 30 patients, tumor and ECS were diagnosed simultaneously. In 12 patients, the NEN diagnosis preceded ECS development, with a median time of 43.5 months (range: 9-96), and 10 of these showed radiological tumor progression at ECS diagnosis. Twenty-one patients had multiple hormone secretion, which correlated with shorter overall survival (OS), p = 0.012 (HR 2.4 (95% CI 1.2-4.9)), as did high morning cortisol, p = 0.037 (HR 2.3 (1.0-5.2)), higher tumor grade, p = 0.044 (HR 2.3 (1.0-5.1)), and diabetes, p = 0.050 (HR 2.4 (1.0-6.0)).

CONCLUSIONS

Multiple hormone secretion, high morning cortisol, higher tumor grade, and diabetes were correlated with shorter OS. Development of ECS in patients with a non-functioning NEN may indicate tumor progression. Multiple hormone secretion should be considered as a bad prognostic sign in ECS patients and should lead to intensified clinical management.

ECTOPIC ADRENOCORTICOTROPIC HORMONE SYNDROME DUE TO METASTATIC PROSTATE CANCER WITH NEUROENDOCRINE DIFFERENTIATION

Objective

Neuroendocrine differentiation of prostate cancer can result in ectopic adrenocorticotropic hormone (ACTH) secretion (EAS) and Cushing syndrome. The aim of this report is to highlight this unusual mechanism of hypercortisolism and its management.

Methods

We report a 73-year-old patient with a history of prostate adenocarcinoma who presented with severe weakness, hyperglycemia, and hypokalemia caused by EAS.

Results

Diagnostic workup showed elevated 24-hour urine cortisol and ACTH levels consistent with EAS. Fluorodeoxyglucose positron emission tomography-computed tomography revealed a hypermetabolic mass in the prostate and metastatic lesions to the liver and bones. Liver biopsy was consistent with small cell carcinoma with positive immunostaining for ACTH. Pleural fluid analysis was consistent with high-grade neuroendocrine carcinoma. The patient underwent chemotherapy with carboplatin and etoposide. Hypercortisolism was treated with ketoconazole, metyrapone, mifepristone, and spironolactone. He suffered complications including opportunistic infections, deep venous thrombosis, and delirium. Given his poor prognosis and clinical decline, the patient opted for comfort measures only in a hospice facility.

Conclusion

Treatment-related neuroendocrine differentiation of prostate cancer is an emerging entity that may be associated with paraneoplastic syndromes including EAS.

Molecular analysis and literature-based hypothesis of an immunonegative prostate small cell carcinoma causing ectopic ACTH syndrome

Ectopic ACTH syndrome (EAS) due to a prostate small cell carcinoma (SCC) is very rare with only 26 cases reported to date and has a poor prognosis. We here describe another case of this disorder that was clinically typical based on prior reports as it showed hypercortisolemia and severe hypokalemia with multiple metastasis. However, our current case of prostate SCC causing EAS is the first to display negative immunostaining for ACTH despite detectable POMC mRNA expression in the primary lesion. ACTH immunonegativity is thought to be associated with a more aggressive disease course and a poorer prognosis although there are few studies of the underlying mechanisms. We explored two possibilities for this finding in our current patient: aberrant POMC processing prevented immunodetection with an anti-ACTH antibody; and the ACTH content per cell was below the threshold for immunodetection due to its rapid secretion or low synthesis. The aberrant processing theory was thought to be less likely because of immunonegative findings even using anti-POMC/ACTH antibodies. As the plasma ACTH levels in our patient were comparable with those reported for previous immunopositive prostate EAS cases, we speculated that the depletion of ACTH may be caused not only by rapid secretion but also by low production levels as a sign of de-differentiation. De-differentiation may therefore explain the mechanism underlying the negative correlation between immunoreactivity for ACTH in EAS and disease aggressiveness. We believe that our present findings will be of use in future prospective studies aimed at confirming the mechanism of immunonegativity.

Dual Paraneoplastic Endocrine Syndromes Heralding Onset of Extrapulmonary Small Cell Carcinoma: A Case Report and Narrative Review

OBJECTIVE

Extrapulmonary small cell carcinoma (EPSCC) is rare and frequent metastases at presentation can complicate efforts to identify a site of origin. In particular, SCC comprises <1% of prostate cancers and has been implicated in castration resistance.

METHODS

Clinical, laboratory, imaging, and pathology data are presented.

RESULTS

A 56-year-old man with locally advanced prostate adenocarcinoma on androgen deprivation therapy presented with a clogged nephrostomy tube. Laboratory results included calcium 13.8 mg/dL (8.5-10.5 mg/dL), albumin 3.6 g/dL (3.5-5 mg/dL), and potassium 2.8 mmol/L (3.5-5.2 mmol/L). Hypercalcemia investigation revealed intact PTH 19 pg/mL (16-87 pg/mL), 25-OH vitamin D 15.7 ng/mL (>30 ng/mL), and PTH-related peptide (PTHrP) 63.4 pmol/L (<2.3 pmol/L). Workup for hypokalemia yielded aldosterone 5.3 ng/dL (<31 ng/dL), renin 0.6 ng/mL/h (0.5-4 ng/mL/h), and 6:00 a.m. cortisol 82 µg/dL (6.7-22.6 µg/dL) with ACTH 147 pg/mL (no ref. range). High-dose Dexamethasone suppression testing suggested ACTH-dependent ectopic hypercortisolism. Contrast-enhanced CT findings included masses in the liver and right renal pelvis, a heterogeneous enlarged mass in the region of the prostate invading the bladder, bilateral adrenal thickening, and lytic lesions in the pelvis and spine. Liver biopsy identified epithelioid malignancy with Ki proliferation index 98% and immunohistochemical staining positive for synaptophysin and neuron-specific enolase, compatible with high-grade small cell carcinoma. Staining for ACTH was negative; no stain for CRH was available. Two weeks after chemotherapy, 6:00 a.m. cortisol normalized and CT scans showed universal improvement.

CONCLUSION

Extensive literature details paraneoplastic syndromes associated with SCC, but we report the first case of EPSCC diagnosed due to onset of dual paraneoplastic syndromes.

Severe Cushing's syndrome due to small cell prostate carcinoma: a case and review of literature

Cushing's syndrome (CS) due to ectopic adrenocorticotrophic hormone (ACTH) is associated with a variety of tumours most of which arise in the thorax or abdomen. Prostate carcinoma is a rare but important cause of rapidly progressive CS. To report a case of severe CS due to ACTH production from prostate neuroendocrine carcinoma and summarise previous published cases. A 71-year-old male presented with profound hypokalaemia, oedema and new onset hypertension. The patient reported two weeks of weight gain, muscle weakness, labile mood and insomnia. CS due to ectopic ACTH production was confirmed with failure to suppress cortisol levels following low- and high-dose dexamethasone suppression tests in the presence of a markedly elevated ACTH and a normal pituitary MRI. Computed tomography demonstrated an enlarged prostate with features of malignancy, confirmed by MRI. Subsequent prostatic biopsy confirmed neuroendocrine carcinoma of small cell type and conventional adenocarcinoma of the prostate. Adrenal steroidogenesis blockade was commenced using ketoconazole and metyrapone. Complete biochemical control of CS and evidence of disease regression on imaging occurred after four cycles of chemotherapy with carboplatin and etoposide. By the sixth cycle, the patient demonstrated radiological progression followed by recurrence of CS and died nine months after initial presentation. Prostate neuroendocrine carcinoma is a rare cause of CS that can be rapidly fatal, and early aggressive treatment of the CS is important. In CS where the cause of EAS is unable to be identified, a pelvic source should be considered and imaging of the pelvis carefully reviewed.

Prevalence and clinical features of the ectopic ACTH syndrome in patients with gastroenteropancreatic and thoracic neuroendocrine tumors

OBJECTIVE

Several series report on the relative contribution of ectopic ACTH syndrome (EAS) in the spectrum of Cushing's syndrome. However, prevalence of EAS in patients with thoracic or gastroenteropancreatic neuroendocrine tumors (GEP-NETs) is currently unknown.

DESIGN

We assessed, in a tertiary referral center, the prevalence of EAS in a large cohort of thoracic and GEP-NET patients including clinical, biochemical, and radiological features; management; and treatment outcome.

METHODS

In total, 918 patients with thoracic or GEP-NETs were studied (1993-2012). Multiple endocrine neoplasia type 1 and small cell lung carcinoma patients were excluded. Differentiation between synchronous, metachronous, and cyclic occurrence of EAS was made.

RESULTS

Out of the 918 patients with thoracic and GEP-NETs (469 males and 449 females; median age 58.7 years (range: 17.3-87.3)), 29 patients (3.2%) had EAS (ten males and 19 females; median age 48.1 years (range: 24.7-77.9)). EAS occurred synchronously in 23 patients (79%), metachronously in four patients (14%), and cyclical in two patients (7%) respectively. NETs causing EAS included lung/bronchus (n=9), pancreatic (n=9), and thymic (n=4). In four patients, the cause of EAS was unknown (n=4). Median overall survival (OS) of non-EAS thoracic and GEP-NET patients was 61.2 months (range: 0.6-249.4). Median OS of EAS patients was 41.4 months (range: 2.2-250.9). After comparison, only the first 5-year survival was significantly shorter (P=0.013) in EAS patients.

CONCLUSION

Prevalence of EAS in this large cohort of patients with thoracic and GEP-NETs was 3.2%. EAS was mostly caused by thoracic and pancreatic NETs. First 5-year survival of EAS patients was shorter compared with non-EAS patients.

Small cell carcinoma of the prostate presenting with Cushing Syndrome. A narrative review of an uncommon condition

Small cell carcinoma (SCC) of the prostate is an uncommon condition; there are very few cases in which presenting symptoms are consistent with Cushing Syndrome (CS). We report a new case in which CS triggers the suspicion of an SCC of the prostate and a review of the published cases of SCC of the prostate presenting with CS. The origin of these neoplasms is still unclear. It may be suspected when laboratory features appear in patients diagnosed with prostatic adenocarcinoma which becomes resistant to specific therapy. SCC usually occurs after the 6th decade. Patients suffering SCC of the prostate presenting with CS usually present symptoms such as hypertension, hyperglycemia, alkalosis or hypokalemia; cushingoid phenotype is less frequent. Cortisol and ACTH levels are often high. Prostatic-specific antigen levels are usually normal. CT scan is the preferred imaging test to localize the lesion, but its performance may be improved by adding other tests, such as FDG-PET scan. All patients have metastatic disease at the time of diagnosis. Lymph nodes, liver and bone are the most frequent metastases sites. Surgery and Ketokonazole are the preferred treatments for CS. The prognosis is very poor: 2- and 5-year survival rates are 27.5 and 14.3%, respectively. Key messages When a patient presents with ectopic Cushing Syndrome but lungs are normal, an atypical localization should be suspected. We should suspect a prostatic origin if Cushing Syndrome is accompanied by obstructive inferior urinary tract symptoms or in the setting of a prostatic adenocarcinoma with rapid clinical and radiological progression with relatively low PSA levels. Although no imaging test is preferred to localize these tumors, FDG-PET-TC can be very useful. Hormone marker scintigraphy (e.g. somatostatin) could be used too. As Cushing Syndrome is a paraneoplastic phenomenon, treatment of the underlying disease may help control hypercortisolism manifestations. These tumors are usually metastatic by the time of diagnosis. They have very poor prognosis.

Diagnosis of prostatic neuroendocrine carcinoma: Two cases report and literature review

Two cases of prostatic neuroendocrine carcinoma (PNEC) imaged by computed tomography (CT) and magnetic resonance imaging (MRI), and literature review are presented. Early enhanced CT, MRI, especially diffusion-weighted image were emphasized, the complementary roles of ultrasound, CT, MRI, clinical and laboratory characteristic’s features in achieving accurate diagnosis were valued in the preoperative diagnosis of PNEC.

UK single centre experience of rare and atypical variant of castrate-resistant prostate cancer: Poorly differentiated neuroendocrine small-cell carcinoma

Background:

We report on the emergence of a rare and atypical variant of castrate-resistant prostate cancer (CRPC) that is characterised by transformation into poorly differentiated neuroendocrine small-cell carcinoma (NSCC). The existence of this variant was previously described in isolated case reports and small case-studies, but as yet there has been no UK series reported in the literature.

Methods:

Between January 2010 and January 2014, eight cases were presented in our local multi-disciplinary team meeting having a diagnosis of NSCC arising on a background of prostate cancer treated with androgen deprivation therapy. We performed a retrospective review of the clinical records of these patients, to identify the mode of presentation, diagnostic investigations, pathological characteristics, and subsequent treatment and survival outcomes.

Results:

The median patient age was 77 years (range, 68 – 84), with a median time interval of 25 months (range, 7 – 83) between the original diagnosis and subsequent transformation to NSCC. The median prostate-specific antigen (PSA) was 4 ng/ml, at presentation. Most patients presented with local progression, combined with high-volume and atypical sites of metastasis (e.g. brain, pancreas and penis). Patients developed a good initial response to platinum-based chemotherapy, but responses were short-lived and prognosis poor, with a median overall survival (OS) of 8 months.

Conclusion:

Prostate NSCC represents an atypical variant of CRPC with significant therapeutic and prognostic implications. Based on our observations, we have proposed a clinical algorithm for early diagnosis and appropriate management of these patients.

Detection of paranasal ectopic adrenocorticotropic hormone-secreting pituitary adenoma by Ga-68-DOTANOC positron-emission tomography-computed tomography

Ectopic adrenocorticotropic hormone (ACTH)-secreting tumors account for approximately 10% of Cushing's syndrome (CS). We present an extremely rare case of a patient with CS caused by an ectopic ACTH-secreting pituitary adenoma (EAPA) of the ethmoid sinus. The tumor was identified by positron-emission tomography-computed tomography (PET/CT) using the somatostatin receptor analogue Ga-68-DOTANOC. Transnasal endoscopic resection was performed and the patient showed significant clinical improvement with normalization of the endocrine pituitary axis. Immunostaining showed a somatostatin receptor 2 and 5-positive ACTH-producing adenoma. In patients with ectopic ACTH secretion, Ga-68-DOTANOC-PET/CT may play an important role in the localization of EAPA. Transnasal endoscopic resection is the therapy of choice.

Expression of melanocortin receptors in human prostate cancer cell lines: MC2R activation by ACTH increases prostate cancer cell proliferation

The melanocortin receptors (MCRs 1-5) are G protein coupled-receptors (GPCRs) that regulate food intake, inflammation, skin pigmentation, sexual function and steroidogenesis. Their peptide ligands, the melanocortins, are α-, β- and γ-melanocyte-stimulating hormone and adrenocorticotropic hormone (ACTH) all of which are secreted from the anterior pituitary gland under hypothalamic control. MC2R binds ACTH but has no affinity for the other melanocortins and is, thereby, pharmacologically different from MCRs that bind those ligands. Evidence suggests that elevated GPCRs transactivate the androgen receptor (AR), the critical mediator of prostate cell growth, and consequently promote prostate cancer cell proliferation. It may be that reduced central melanocortin signaling is coincidental with reversal of prostate cancer cachexia, but no data are available on the expression of, or the role for, MCRs in prostate cancer. Here, we show that MCR (1-5) mRNAs are expressed in androgen-dependent LNCaP and androgen-independent PC3 and DU-145 human prostate cancer cell lines. Further, MC2R, the specific target of ACTH, is expressed in LNCaP, PC3 and DU-145 cells. Among the several synthetic MCR peptide ligands that we used, only ACTH promoted concentration-dependent cell proliferation in the three cell lines as shown by MTT cell proliferation assay. In LNCaP cells, the effect was additive with testosterone stimulation and was partially blunted with SHU9119, a non-selective MCR antagonist. In the same cells, ACTH induced cAMP production and increased AR nuclear labeling in immunocytochemical assays. Our observations suggest that MC2R is involved in prostate carcinogenesis and that targeting MC2R signaling may provide a novel avenue in prostate carcinoma treatment.

Hypophosphatemia related to paraneoplastic Cushing syndrome in prostate cancer: cure after bilateral adrenalectomy

We report the case of a 71-year-old man with progressive metastatic prostate cancer in whom simultaneous occurrence of paraneoplastic Cushing syndrome (CS) and tumor-induced osteomalacia (TIO) initially was suspected. However, the evolution of biochemical markers of phosphate metabolism during disease course and after bilateral adrenalectomy argued against the diagnosis of TIO. Despite the persistence of progressive prostate cancer, CS and hypophosphatemia resolved in parallel after bilateral adrenalectomy. Thus, these data suggest that paraneoplastic CS per se was involved in the pathogenesis of hypophosphatemia. Calcitriol and intact fibroblast growth factor 23 (FGF23) levels were within the reference range at onset, which is inappropriate in the setting of severe hypophosphatemia. All parameters of phosphate metabolism normalized after resolution of hypercortisolism. Based on the known suppressive effect of glucocorticoids (GCs) on bone remodeling and the inverse relationship between bone turnover rate and circulating FGF23 levels, we postulate that GCs interfere indirectly with phosphate homeostasis by inducing inappropriate FGF23 production and release. This mechanism could further aggravate the hypophosphatemia resulting from GC-induced inhibition of intestinal phosphate absorption. Studies directed at the identification of the molecular pathways in bone mediating the interference of GCs with phosphate metabolism are warranted.

Unusual cause of ectopic secretion of adrenocorticotropic hormone: Cushing syndrome attributable to small cell prostate cancer

OBJECTIVE

To report a rare cause of ectopic adrenocorticotropic hormone (ACTH) secretion leading to severe Cushing syndrome.

METHODS

We describe the clinical presentation and management of a case of Cushing syndrome attributable to ectopic ACTH secretion from small cell cancer of the prostate.

RESULTS

In a 70-year-old man with hypertension and diabetes, congestive heart failure developed. He was found to have severe hypokalemia (serum potassium, 1.7 mEq/L) and a huge pelvic mass on a computed tomographic scan performed because of a complaint of urinary retention. Transurethral biopsy of the prostate showed features of small cell prostate cancer. Hormonal evaluation revealed a high urine free cortisol excretion of 6,214.5 microg/d (reference range, 36 to 137), confirming the diagnosis of Cushing syndrome. A serum ACTH level was elevated at 316 ng/dL (reference range, 10 to 52). An overnight high-dose (8 mg orally) dexamethasone suppression test was positive (serum cortisol levels were 43.2 and 41 microg/dL before and after suppression, respectively), and magnetic resonance imaging of the pituitary gland disclosed no abnormalities. A prostate biopsy specimen showed small cell prostate cancer with positive staining for ACTH. The tumor was found to be unresectable, and the poor condition of the patient did not allow for bilateral adrenalectomy. He was treated with ketoconazole and metyrapone, which yielded good temporary control of his Cushing syndrome (24-hour urine free cortisol decreased to 55.2 microg/d). He received 1 cycle of chemotherapy (etoposide and cisplatin), but he died 6 months later as a result of sepsis.

CONCLUSION

Small cell prostate cancer is a rare subtype that can be associated with ectopic secretion of ACTH and severe Cushing syndrome. With this subtype of prostate cancer, Cushing syndrome should be considered and appropriately managed.