Gabriel Zada, John D. Carmichael, and Warren R. Selman
John D. Carmichael, Gabriel Zada, and Warren R. Selman
Vivien Bonert, Namrata Bose, and John D. Carmichael
Diagnosing Cushing's syndrome is challenging and is further hampered when investigations are performed in a patient with cyclic Cushing's syndrome. A subset of patients with Cushing's syndrome exhibit periods of abnormal cortisol secretion with interspersed normal secretion. Patients can have periods of clinical improvement during these quiescent phases or remain symptomatic. Initial diagnostic testing can be challenging because of the unpredictable durations of the peak and trough phases, and it is especially challenging when the diagnosis of cyclic Cushing's syndrome has not yet been determined. Here, the authors present the case of a patient with Cushing's disease with a pathology-proven adrenocorticotropic hormone (ACTH)–secreting pituitary adenoma and whose initial inferior petrosal sinus sampling (IPSS) results were deemed indeterminate; further studies elucidated the diagnosis of cyclic Cushing's syndrome. Repeat IPSS was diagnostic of a central source for ACTH secretion, and the patient was treated successfully with transsphenoidal resection. Literature concerning the diagnosis and management of cyclic Cushing's syndrome is also reviewed.
Charles Ashton, Suhn K. Rhie, John D. Carmichael, and Gabriel Zada
Prior profiling of the human pituitary adenoma (PA) DNA methylome showed the potassium channel subunit–encoding gene KCNAB2 to be highly differentially methylated between nonfunctional PAs (NFPAs) and growth hormone (GH)–secreting PAs, with greater KCNAB2 methylation detected in secretory PAs. KCNAB2 encodes an aldo-keto reductase that, among other things, negatively regulates members of the voltage-gated potassium channel (Kv) family. In this study, the authors aimed to determine whether modulation of Kcnab2 expression would alter GH secretion in the GH3 mammosomatotroph rat cell line. In addition, they examined whether dosing GH3 cells with the antiarrhythmic drug quinidine, a known inhibitor of Kv and voltage-gated sodium channels, would affect hormonal secretion.
Previously generated RNA-seq data were reanalyzed to compare KCNAB2 expression levels in human NFPAs and GH-secreting PAs. Kcnab2 was overexpressed in GH3 cells using plasmid transfection and knocked down using shRNA, with confirmation by quantitative polymerase chain reaction (qPCR). GH concentrations in cell culture supernatants collected 24 hours after cell seeding were measured using enzyme-linked immunosorbent assay (ELISA). Separately, quinidine was administered to GH3 cells at graduated doses. GH and prolactin concentrations in supernatants collected 48 hours after quinidine treatment were measured by fluorometric immunoassay.
Modulation of expression at the transcript level in GH3 cells resulted in proportionate changes in the expression of GH mRNA and secretion of GH peptide, as confirmed by qPCR and ELISA. Specifically, partial knockdown of Kcnab2 was associated with fewer GH RNA transcripts and less GH secretion compared with controls, while augmentation of Kcnab2 expression was associated with more GH transcripts and secretion than the controls. Administration of quinidine (≥ 50 µM) reduced both GH and prolactin secretion in a dose-dependent fashion (p ≤ 0.05).
GH secretion in a somatotroph cell line is partially dependent on KCNAB2 gene expression and may be mitigated in vitro by quinidine. These results collectively suggest a potential new target and pharmacological candidate to be considered in the development of clinical therapeutics for acromegaly.
Justin Seltzer, Charles E. Ashton, Thomas C. Scotton, Dhiraj Pangal, John D. Carmichael, and Gabriel Zada
Functional corticotroph pituitary adenomas (PAs) secrete adrenocorticotropic hormone (ACTH) and are the cause of Cushing's disease, which accounts for 70% of all cases of Cushing's syndrome. Current classification systems for PAs rely primarily on laboratory hormone findings, tumor size and morphology, invasiveness, and immunohistochemical findings. Likewise, drug development for functional ACTH-secreting PAs (ACTH-PAs) is limited and has focused largely on blocking the production or downstream effects of excess cortisol. The authors aimed to summarize the findings from previous studies that explored gene and protein expression of ACTH-PAs to prioritize potential genetic and protein targets for improved molecular diagnosis and treatment of Cushing's disease.
A systematic literature review was performed using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. A PubMed search of select medical subject heading (MeSH) terms was performed to identify all studies that reported gene- and protein-expression findings in ACTH-PAs from January 1, 1990, to August 24, 2014, the day the search was performed. The inclusion criteria were studies on functional ACTH-PAs compared with normal pituitary glands, on human PA tissue only, with any method of analysis, and published in the English language. Studies using anything other than resected PA tissue, those that compared other adenoma types, those without baseline expression data, or those in which any pretreatment was delivered before analysis were excluded.
The primary search returned 1371 abstracts, of which 307 were found to be relevant. Of those, 178 were selected for secondary full-text analysis. Of these, 64 articles met the inclusion criteria and an additional 4 studies were identified from outside the search for a total of 68 included studies. Compared with the normal pituitary gland, significant gene overexpression in 43 genes and 22 proteins was reported, and gene underexpression in 58 genes and 15 proteins was reported. Immunohistochemistry was used in 39 of the studies, and reverse transcriptase polymerase chain reaction was used in 26 of the studies, primarily, and as validation for 4 others. Thirteen studies used both immunohistochemistry and reverse transcriptase polymerase chain reaction. Other methods used included microarray, in situ hybridization, Northern blot analysis, and Western blot analysis. Expression of prioritized genes emphasized in multiple studies were often validated on both the gene and protein levels. Genes/proteins found to be overexpressed in ACTH-PAs relative to the normal pituitary gland included hPTTG1/securin, NEUROD1/NeuroD1 (Beta2), HSD11B2/11β-hydroxysteroid dehydrogenase 2, AKT/Akt, protein kinase B, and CCND1/cyclin D1. Candidate genes/proteins found to be underexpressed in ACTH-PAs relative to the normal pituitary gland included CDKN1B/p27Kip1, CDKN2A/p16, KISS1/kisspeptin, ACTHR/ACTH-R, and miR-493.
On the basis of the authors' systematic review, many significant gene and protein targets that may contribute to tumorigenesis, invasion, and hormone production/secretion of ACTH have been identified and validated in ACTH-PAs. Many of these potential targets have not been fully analyzed for their therapeutic and diagnostic potential but may represent candidate molecular targets for biomarker development and drug targeting. This review may help catalyze additional research efforts using modern profiling and sequencing techniques and alteration of gene expression.
Robert J. Spinner, Stephen W. Carmichael, and John L. D. Atkinson
Justin Seltzer, Joshua Lucas, Deborah Commins, Olga Lerner, Alexander Lerner, John D. Carmichael, and Gabriel Zada
Ectopic pituitary adenomas are exceedingly rare entities that are often misdiagnosed. The resulting delay in diagnosis may be particularly concerning in the case of Cushing syndrome caused by an ectopic adrenocorticotropic hormone (ACTH)–secreting pituitary adenoma. Although the total resection of ectopic adenomas results in rapid and durable remission, persistent Cushing syndrome is often associated with permanently damaging invasive procedures and significantly higher risk of mortality.
The authors report the case of a 48-year-old man with ACTH-dependent Cushing syndrome. On the morning before surgery, his serum cortisol measured 51 μg/dl, his ACTH level was 195.7 pg/ml, and his urinary free cortisol level was 2109 μg/day. Serum cortisol was not suppressed with the administration of high-dose dexamethasone. Imaging showed separate masses in both the sphenoid sinus and the pituitary gland, complicating the diagnostic process and requiring pathological assessment of both masses. No other abnormalities were found on thoracic, abdominal, or pelvic scans. Gross-total resection of both lesions was accomplished via an endoscopic endonasal transsphenoidal approach. Pathology confirmed an ectopic ACTH pituitary adenoma of the sphenoid sinus and a Crooke hyaline change of the pituitary gland. The patient achieved stable hormonal remission without significant postoperative complications, returned to full activity within 3 months, and remained disease free nearly 1 year after tumor resection.
In a systematic literature review, the authors identified 41 cases of ectopic ACTH-secreting pituitary adenomas, including 18 arising in the sphenoid sinus without direct involvement of the sella. Including the case described here, the total number of ectopic ACTH pituitary adenomas arising in the sphenoid sinus was 19, and the total number of ectopic ACTH pituitary adenomas without regard to location was 42. For the 19 patients with adenomas found in the sphenoid sinus, ages ranged from 16 to 76 years, and there were 15 women and 4 men. The mean and median diameters of the resected sphenoid masses were 13.9 and 8 mm, respectively, with a range of 3–55 mm. Seven were microadenomas (< 1 cm). Fifteen of the 19 cases reported serum ACTH and morning cortisol levels, the means of which were 106.7 pg/ml and 32.5 μg/dl, respectively. Gross-total tumor resection was achieved in all patients except one, and in all of them durable hormonal remission of Cushing syndrome was achieved (mean follow-up time 20 months).
Ectopic pituitary adenomas are rare but important causes of Cushing syndrome and related endocrinopathies, particularly because of the rapid onset and severity of symptoms with atypical presentation. Ectopic pituitary adenomas, especially those in the nasal cavity, nasopharynx, or paranasal sinuses, are easily misidentified. Any patient presenting with signs and symptoms of Cushing syndrome without any obvious pituitary adenoma or other sources of hypercortisolemia should be thoroughly screened for an ectopic adenoma. However, as with the case presented here, the coincident existence of a sellar mass should not preclude the possibility of an ectopic source. There should be a high degree of clinical suspicion for any mass in the general area surrounding the sella when evaluating Cushing syndrome.
Daniel Wilson, Diana L. Jin, Timothy Wen, John D. Carmichael, Steven Cen, William J. Mack, and Gabriel Zada
Cushing's disease (CD) is a potentially lethal neuroendocrinopathy that often requires specialized multidisciplinary treatment to achieve optimized outcomes. The authors analyzed data pertaining to patient, hospital, and admission characteristics as they relate to outcomes following transsphenoidal surgery (TSS) in more than 5500 patients treated for CD.
The Nationwide Inpatient Sample (NIS) database was used to identify all patients admitted with CD between 2002 and 2010. A variety of patient demographic data (e.g., age, sex, race, payer status), hospital variables (e.g., bed size, TSS volume, teaching status), and admission subtypes (e.g., elective, emergency) were tested for association with postoperative endocrine and nonendocrine complications, mortality, nonroutine discharge, length of stay, and total hospital charges. All tests were performed using univariate analysis followed by multivariate analysis, with 4 models tested via an additive methodology. Statistical significance was defined as a p value < 0.05 for all analyses.
From 2002 to 2010, 5527 individuals who were admitted for TSS (54 biopsies, 4254 partial resections, and 1271 total resections; 5579 total TSS procedures) were identified as patients with CD. There were 25 deaths following TSS, resulting in a mortality incidence rate of 0.45%. Nonendocrine and endocrine complications were reported in 22.4% and 11.1% of patients, respectively. The most common nonendocrine complications were postoperative neurological complications (6.98%) and mechanical ventilation (1.71%). Diabetes insipidus was reported in 14.79% of patients. In a multivariate analysis, patients with Medicare were at increased risk of nonendocrine complications (relative risk [RR] 2.24, 95% CI 1.15–4.38; p = 0.02). Patients with Medicare had increased risk of higher charges (RR 1.89, 95% CI 1.04–3.45; p = 0.04), as did those with Medicaid (RR 1.93, 95% CI 1.10–3.41; p = 0.02). Additionally, as compared with white patients, Hispanic patients had an increased rate of higher charges (RR 1.86, 95% CI 1.12–3.10; p = 0.02). Patients whose age was less than 40 years had a higher risk of developing diabetes insipidus (RR 1.39, 95% CI 1.0–1.93; p = 0.05). When compared with those in northeast hospitals, patients in western hospitals were more likely to experience nonendocrine complications (RR 1.85, 95% CI 0.99–3.46; p = 0.05) and endocrine complications (RR 1.98, 95% CI 1.28–3.07; p < 0.01). Patients treated in teaching hospitals were at significantly lower risk of incurring higher hospital charges (RR 0.49, 95% CI 0.28–0.85; p = 0.01). Patients with emergency admissions had a risk of higher hospital charges (RR 3.06, 95% CI 1.26–7.46; p = 0.01) and nonendocrine complications (RR 3.18, 95% CI 1.22–8.28; p = 0.02).
This review of NIS data in more than 5500 patients treated surgically for CD pointed to major outcome disparities predicted primarily by payer status, admission type, and hospital region. Identification and targeting of such barriers to quality health care in patients with CD may help optimize patient outcomes on a national level and present an opportunity to improve access of high-risk patient subgroups to specialty centers of excellence.
Matthew S. Agam, Michelle A. Wedemeyer, Bozena Wrobel, Martin H. Weiss, John D. Carmichael, and Gabriel Zada
Pituitary adenomas (PAs) are benign neoplasms that are frequently encountered during workup for endocrinopathy, headache, or visual loss. Transsphenoidal surgery remains the first-line approach for PA resection. The authors retrospectively assessed complication rates associated with transsphenoidal PA resection from an institutional database.
A retrospective analysis of 1153 consecutive transsphenoidal pituitary adenoma resections performed at the Keck Hospital of USC between November 1992 and March 2017 was conducted. Microscopic transsphenoidal resection was performed in 85.3% of cases, and endoscopic transsphenoidal resection was performed in 14.7%. Analysis of perioperative complications and patient and tumor risk factors was conducted.
The overall median hospital stay was 3 days. There was 1 perioperative death (0.1%). Surgical complications included postoperative cerebrospinal fluid leak (2.6%), epistaxis (1.1%), postoperative hematoma (1.1%), meningitis (1.0%), cranial nerve paresis (0.8%), hydrocephalus (0.8%), vision loss (0.6%), stroke (0.3%), abdominal hematoma or infection (0.2%), carotid artery injury (0.1%), and vegetative state (0.2%). Perioperative medical complications included bacteremia/sepsis (0.5%), pneumonia (0.3%), myocardial infarction (0.3%), and deep venous thrombosis/pulmonary embolism (0.1%). Endocrine complications were the most frequent, including transient diabetes insipidus (4.3%), symptomatic hyponatremia (4.2%), new hypopituitarism (any axis) (3.6%), permanent diabetes insipidus (0.3%), and adrenal insufficiency (0.2%). There were no significant differences between microscopic and endoscopic approaches with regard to surgical complications (6.4% vs 8.8%, p = 0.247) or endocrine complications (11.4 vs 11.8%, p = 0.888). Risk factors for surgical complications included prior transsphenoidal surgery (11.4% vs 6.8%, p = 0.025), preoperative vision loss (10.3% vs 6.8%, p = 0.002), and presence of PA invasion on MRI (8.5% vs 4.4%, p = 0.007).
In this single tertiary center study assessing complications associated with transsphenoidal PA resection, the rate of death or major disability was 0.26%. Risk factors for complications included prior surgical treatment and PA invasion. No differences in complication rates between endoscopic and microscopic surgery were observed. When performed at experienced pituitary centers, transsphenoidal surgery for PAs may be performed with a high degree of safety.
Anna Jackanich, Sherwin Tavakol, Ben A. Strickland, Martin Rutkowski, Dina Kamel, John D. Carmichael, Martin Weiss, and Gabriel Zada
Hypothalamic-pituitary-adrenal (HPA) axis dysfunction is a well-documented complication of transsphenoidal craniotomy (TSC) for sellar lesions. The authors aimed to assess their multidisciplinary approach to the diagnosis and treatment of postoperative hypocortisolemia utilizing conservative screening methods.
The authors performed a retrospective review of 257 patients who underwent TSC for pituitary adenoma (PA) or Rathke cleft cyst (RCC) at the University of Southern California between 2012 and 2017. Patients with preoperative adrenal insufficiency, Cushing’s disease, or < 3 months of postoperative follow-up were excluded. Patient demographics, pathology, tumor characteristics, and complications were recorded. Postoperative day 1 (POD1) morning serum cortisol was assessed in all patients. Hypocortisolemia on POD1 (serum cortisol < 5 μg/dl) prompted a 7 am cortisol level measurement on POD 2 (POD2). Clinical signs and symptoms of hypocortisolemia were consistently monitored. After two serum cortisol levels < 5 μg/dl, or one serum level < 5 μg/dl plus a high clinical suspicion for HPA dysfunction, high-risk patients received glucocorticoid supplementation.
Data on 165 patients were included in the analysis; there were 101 women (61.2%) and 64 men (38.7%). Preoperative diagnoses included nonfunctional adenoma (n = 97, 58.7%), growth hormone–secreting adenoma (n = 37, 22.4%), RCC (n = 18, 10.9%), prolactinoma (n = 8, 4.8%), and other (n = 5, 3.0%). One hundred thirty-eight patients (63.0%) had either suprasellar extension or cavernous sinus invasion. POD1 hypocortisolemia was diagnosed in 8 patients (4.8%). Of these patients, 2 (1.2%) were clinically asymptomatic and had normalized POD2 cortisol levels. Six patients (3.6%) had clinical symptoms and POD2 cortisol levels confirming HPA axis deficiency. Of these 6 patients treated with early glucocorticoid replacement, 2 patients recovered HPA axis function during follow-up, making the incidence of new, permanent HPA axis deficiency 2.5%.
In the authors’ institutional review, all patients warranting postoperative glucocorticoid replacement had both complicated surgical courses and associated clinical symptoms of hypocortisolemia. The authors’ algorithm of withholding steroids until patients demonstrate clear evidence of postoperative hypocortisolemia is safe and clinically efficacious. Their data further suggest that routine postoperative cortisol screening may not be necessary following an uncomplicated operative resection, with gland preservation and the absence of clinical symptoms indicative of HPA dysfunction.