Intraoperative multiple-staged resection and tumor tissue identification using frozen sections provide the best result for the accurate localization and complete resection of tumors in Cushing's disease

An individualized approach to the management of Cushing disease

Cushing disease caused by an adrenocorticotropic hormone (ACTH)-secreting pituitary corticotroph adenoma leads to hypercortisolaemia with high mortality due to metabolic, cardiovascular, immunological, neurocognitive, haematological and infectious conditions. The disorder is challenging to diagnose because of its common and heterogenous presenting features and the biochemical pitfalls of testing levels of hormones in the hypothalamic-pituitary-adrenal axis. Several late-night salivary cortisol and 24-h urinary free cortisol tests are usually required as well as serum levels of cortisol after a dexamethasone suppression test. MRI might only identify an adenoma in 60-75% of patients and many adenomas are small. Therefore, inferior petrosal sinus sampling remains the gold standard for confirmation of ACTH secretion from a pituitary source. Initial treatment is usually transsphenoidal adenoma resection, but preoperative medical therapy is increasingly being used in some countries and regions. Other management approaches are required if Cushing disease persists or recurs following surgery, including medications to modulate ACTH or block cortisol secretion or actions, pituitary radiation, and/or bilateral adrenalectomy. All patients require lifelong surveillance for persistent comorbidities, clinical and biochemical recurrence, and treatment-related adverse effects (including development of treatment-associated hypopituitarism). In this Review, we discuss challenges in the management of Cushing disease in adults and provide information to guide clinicians when planning an integrated and individualized approach for each patient.

Dexamethasone suppression for 18F-FDG PET/CT to localize ACTH-secreting pituitary tumors

BACKGROUND

18Fluorine-Fluoro-deoxy-glucose (18F-FDG) positron emission tomography (PET) is widely used for diagnosing various malignant tumors and evaluating metabolic activities. Although the usefulness of 18F-FDG PET has been reported in several endocrine diseases, studies on pituitary disease are extremely limited. To evaluate whether dexamethasone (DEX) suppression can improve 18F-FDG PET for the localization of adrenocorticotropic hormone-secreting adenomas in the pituitary gland in Cushing's disease (CD).

METHODS

We included 22 patients with CD who underwent PET imaging before and after DEX administration. We compared the success rates of PET before and after DEX suppression, magnetic resonance imaging (MRI), and bilateral inferior petrosal sinus sampling (BIPSS). We determined the final locations of adenomas based on intraoperative multiple-staged resection and tumor tissue identification using frozen sections. Standardized uptake value (SUV) were analyzed to confirm the change of intensity of adenomas on PET.

RESULTS

Twenty-two patients were included (age at diagnosis: 37 [13-56] years), and most were women (90.91%). Pituitary adenomas compared to normal pituitaries showed increased maximum SUV after DEX suppression but without statistical significance (1.13 versus. 1.21, z=-0.765, P = 0.444). After DEX suppression, the mean and maximum SUV of adenomas showed a positive correlation with nadir cortisol levels in high-dose DEX suppression test (Rho = 0.554, P = 0.007 and Rho = 0.503, P = 0.017, respectively). In reference sites, mean SUV of cerebellum was significantly decreased (7.65 vs. 6.40, P = 0.006*), but those of the thalamus and gray matter was increased after DEX suppression (thalamus, 8.70 vs. 11.20, P = 0.010*; gray matter, 6.25 vs. 7.95, P = 0.010*).

CONCLUSION

DEX suppression did not improve 18F-FDG PET/CT localization in patients with CD.

Pituitary surgery in Cushing's disease: first line treatment and role of reoperation

Cushing's disease is the most common cause of endogenous hypercortisolemia, and transsphenoidal surgery remains the first line therapy for removal of the ACTH-secreting adenoma. While post-operative remission rates are high in experienced hands, there remains a 2% risk of recurrence per year. Patients with the highest chance for cure are those with small, non-invasive tumors that are visible on pre-operative MRI and identified during surgery and are performed by high-volume pituitary neurosurgeons. Surgery for persistent or recurrent disease is frequently indicated and is most successful in the hands of experienced surgeons and in cases where tumor is visible on MRI.

Perioperative management of endoscopic transsphenoidal pituitary surgery

The contemporary embrace of endoscopic technology in the approach to the anterior skull base has altered the perioperative landscape for patients requiring pituitary surgery. Utility of a multi-disciplinary unit in management decisions facilitates the delivery of optimal care. Evolution of technology and surgical expertise in pituitary surgery mandates ongoing review of all components of the care central to these patients. The many areas of potential variability in the pre, intra and post-operative timeline of pituitary surgery are readily identifiable. Core undertakings and contemporary controversies in the peri-operative management of patients undergoing endoscopic transsphenoidal pituitary surgery are assessed against the available literature with a view to providing guidance for the best evidence-based practice.

Usefulness of prolactin measurement in inferior petrosal sinus sampling with desmopressin for Cushing's syndrome

Background: Bilateral inferior petrosal sinus sampling (IPSS) is used to distinguish pituitary from ectopic adrenocorticotropin (ACTH) excess in patients with ACTH-dependent Cushing's syndrome. Our objective was to examine the utility of prolactin measurement during IPSS with desmopressin (DDAVP) stimulation in localization of the source of ACTH excess.Method: Retrospective review of 20 patients with ACTH-dependent Cushing's syndrome who underwent IPSS with DDAVP stimulation. Baseline, DDAVP-stimulated, and prolactin-normalized ACTH IPS:P (inferior petrosal sinus to peripheral) ratios were calculated. Cut-off values for each test were obtained from receiver-operating characteristic (ROC) curve analysis.Results: Fifteen patients had Cushing disease (CD), and five were diagnosed with ectopic ACTH syndrome (EAS). For the baseline ACTH IPS:P ratio of ≥2, the diagnostic sensitivity (80%), specificity (100%), positive predictive value (PPV) (100%) and negative predictive value (NPV) (62.5%) were calculated. These values for DDAVP-stimulated IPS:P ACTH ratio ≥ 3, were 86.7%, 100%, 100% and 71.4%, respectively. The corresponding value for the prolactin-normalized ACTH IPS:P ratio ≥ 0.8 were 86.6%, 80%, 92.8% and 66.7%. The cut-off value for the baseline, DDAVP-stimulated and prolactin-normalized ACTH IPS:P ratios were 1.76, 3.9, and 0.33, respectively.Conclusion: Prolactin-normalized ACTH IPS:P ratio measurement showed comparable sensitivity and less specificity than baseline/DDAVP-stimulated IPS/P ACTH ratios. Moreover, when baseline and stimulated IPS/P ACTH tests were discordant, prolactin-normalized ACTH IPS: P ratio correctly localized the source of ACTH excess. The sensitivity of the test increased, applying a prolactin-normalized ACTH IPS: P ratio ≥0.33.

The Utility of Intraoperative Cytological Smear and Frozen Section in the Surgical Management of Patients with Cushing's Disease due to Pituitary Microadenomas

Cushing's disease (CD) is most commonly caused by a microadenoma, which at surgical exploration may not provide adequate tissue for pathologic diagnosis using standard techniques. We wished to determine the accuracy of intraoperative pathologic examination and whether the addition of intraoperative cytology increased the diagnostic yield. We reviewed the pathology reports from 403 operations on 341 patients with CD microadenomas from a single institution. The concordance rates of intraoperative diagnoses (cytology and frozen) with the final (paraffin section) pathological diagnosis were calculated. The overall pathologic confirmation of an adenoma (by either cytology, frozen, or paraffin section) was compared with the result from a historical cohort (using only standard frozen section analysis but not intraoperative cytology) and the pooled result from a meta-analysis of previously published data. The concordance rate between frozen section diagnosis and paraffin section histology was 390/403 (96.8%). The concordance rate between cytological smear and paraffin section histology was 213/246 (86.6%). In 54 cases (13.4%) with ultimate remission, pathologic confirmation was obtained only on intraoperative pathology (frozen section or cytology). Overall, pathologic confirmation was obtained in 326 operations (80.9%) by at least one pathological modality. The overall pathological confirmation of an adenoma was greater after the introduction of intraoperative cytology when compared with the historical control (67.1%, p = 0.015), and compared with the pooled rate of published data from the meta-analysis (72.1%, p < 0.001). Our findings suggest that addition of intraoperative cytological analyses during surgery for CD is an additional useful diagnostic tool for both neurosurgeons and pathologists.

Hormonal aggressiveness according to the expression of cellular markers in corticotroph adenomas

PURPOSE

The molecular mechanisms underlying tumor growth in Cushing's disease (CD) still remain a challenge. Moreover, clinical manifestations of CD may vary depending on hormonal activity; however, factors involved in the hormonal aggressiveness of adrenocorticotropic hormone (ACTH)-secreting pituitary tumors have not been fully clarified. We investigated the association between the expression of cellular markers regarding pituitary tumor progression and initial or postoperative hormone levels in patients with CD.

METHODS

Tumor tissues from 28 corticotroph adenomas (female 26, male 2, mean age 39.21 ± 10.39 years) were subject to immunohistochemical study using the following antibodies: pituitary tumor-transforming gene 1 (PTTG1), cyclin D1, p16, p27, brahma related-gene 1 (Brg1), and Ki-67. We then analyzed the relationship between each cellular marker expression and hormone levels, including 24 h urinary free cortisol (UFC), plasma ACTH, and serum cortisol.

RESULTS

PTTG1 and Ki-67 were expressed in 100% and 50% of patients, respectively. However, the levels did not reflect initial hormonal activity. The cyclin D1-negative group showed higher serum cortisol levels compared to the cyclin D1-positive group (p = 0.01). The 24 h UFC levels were significantly higher in the p27-negative group than in the p27-positive group (p = 0.04), whereas the Brg1-positive group revealed higher serum cortisol levels than in the Brg1-negative group (p = 0.02).

CONCLUSIONS

Although PTTG1 and Ki-67 play an essential role in developing ACTH-secreting tumors, cyclin D1, p27, and Brg1 may be better biomarkers to determine hormonal aggressiveness of the tumor. Further research is needed to understand the influence of cellular markers on hormonal activity in CD.

The experience with transsphenoidal surgery and its importance to outcomes

PURPOSE

Surgical experience is considered paramount for excellent outcome of transsphenoidal surgery (TSS). However, objective data demonstrating the surgical success in relation to the experience of pituitary surgery units or individual experience of pituitary surgeons is sparse.

METHODS

Based on literature data, we have investigated the influence of experience with TSS for pituitary adenomas on endocrinological remission rates and on operative complications. The surgical experience was assessed by calculating the number of transsphenoidal operations per year.

RESULTS

For TSS of microprolactinomas, mean remission rates were 77% in centers with < 2 operations per year for microprolactinomas, 82% with 2-4 operations, 84% with 4-6 operations, and 91% with > 6 operations. A yearly experience with more than 10 initial operations for Cushing's disease (CD) warrants a remission rate exceeding 70%. Remission rates in CD exceeding 86% have only been reported for single surgeon series. Extraordinarily high complication rates were found in some series with < 25 yearly total operations for pituitary adenomas. Major vascular complications were less than 2% and revision rates for rhinorrhea usually < 2.5% in centers performing > 25 transsphenoidal operations per year.

CONCLUSIONS

We conclude that a center with experience of > 25 transsphenoidal operations for pituitary adenomas per year provides a high likelihood of safe TSS. Surgery for CD requires a particularly high level of practice to guarantee excellent remission rates. The endocrinologist has the unique opportunity to audit the surgical success by hormone measurement and to refer patients to neurosurgeons with proven excellence.

Clinical Guidelines for the Diagnosis and Treatment of Cushing's Disease in Korea

Cushing's disease (CD) is a rare disorder characterized by the overproduction of adrenocorticotropic hormone due to a pituitary adenoma that ultimately stimulates excessive cortisol secretion from the adrenal glands. Prior to the detection of pituitary adenomas, various clinical signs of CD such as central obesity, moon face, hirsutism, and facial plethora are usually already present. Uncontrolled hypercortisolism is associated with metabolic, cardiovascular, and psychological disorders that result in increased mortality. Hence, the early detection and treatment of CD are not only important but mandatory. Because its clinical manifestations vary from patient to patient and are common in other obesity-related conditions, the precise diagnosis of CD can be problematic. Thus, the present set of guidelines was compiled by Korean experts in this field to assist clinicians with the screening, diagnoses, and treatment of patients with CD using currently available tests and treatment modalities.

Molecular basis of pharmacological therapy in Cushing's disease

Cushing's disease (CD) is a severe endocrine condition caused by an adrenocorticotropin (ACTH)-producing pituitary adenoma that chronically stimulates adrenocortical cortisol production and with potentially serious complications if not or inadequately treated. Active CD may produce a fourfold increase in mortality and is associated with significant morbidities. Moreover, excess mortality risk may persist even after CD treatment. Although predictors of risk in treated CD are not fully understood, the importance of early recognition and adequate treatment is well established. Surgery with resection of a pituitary adenoma is still the first line therapy, being successful in about 60-70 % of patients; however, recurrence within 2-4 years may often occur. When surgery fails, medical treatment can reduce cortisol production and ameliorate clinical manifestations while more definitive therapy becomes effective. Compounds that target hypothalamic-pituitary axis, glucocorticoid synthesis or adrenocortical function are currently used to control the deleterious effects of chronic glucocorticoid excess. In this review we describe and analyze the molecular basis of the drugs targeting the disease at central level, suppressing ACTH secretion, as well as at peripheral level, acting as adrenal inhibitors, or glucocorticoid receptor antagonists. Understanding of the underlying molecular mechanisms in CD and of glucocorticoid biology should promote the development of new targeted and more successful therapies in the future. Indeed, most of the drugs discussed have been tested in limited clinical trials, but there is potential therapeutic benefit in compounds with better specificity for the class of receptors expressed by ACTH-secreting tumors. However, long-term follow-up with management of persistent comorbidities is needed even after successful treatment of CD.