Supradiaphragmatic ectopic adrenocorticotropic hormone-secreting adenoma

Clinical and radiological presentation of parasellar ectopic pituitary adenomas: case series and systematic review of the literature

PURPOSE

Parasellar ectopic pituitary adenomas (pEPAs) are extremely rare tumors located out of the sella turcica. PEPAs are heterogeneous entities in terms of anatomical localization and secretion of anterior pituitary hormones.

METHODS

Multicenter retrospective study. Clinical charts' consultation of patients diagnosed with parasellar lesions, to identify all subjects fulfilling the diagnostic criteria of parasellar EPAs. Systematic review of the literature focused on the medical management of prolactin-secreting pEPAs and on the prevalence of radiological bone invasion in pEPAs.

RESULTS

We identified four cases of pEPAs: (1) 54-year-old female with a prolactin-secreting suprasellar EPA successfully treated with cabergoline; (2) 74-year-old male with a non-functioning EPA of the sphenoidal sinus treated with endoscopic transsphenoidal surgery; (3) 75-year-old female with a giant lesion of the skull base (maximum diameter 7.2 cm) diagnosed as a non-functioning EPA after biopsy; (4) 49-year-old male with a silent corticotroph EPA of the sphenoidal sinus and clivus. Three out of four cases had radiological evidence of invasion of the surrounding bone structures. A systematic review of the literature highlighted that medical therapy can be effective in prolactin-secreting pEPAs. Overall, we found mention of local invasiveness in 65/147 cases (44.2%), confirmed by radiological signs of bone invasion/erosion.

CONCLUSION

Our experience confirms the heterogeneity of pEPAs in terms of clinical and radiological presentation, as well as hormone secretion. PEPAs show a high frequency of radiological bone invasion, though similar to that of sellar pituitary adenomas. Although extremely rare, pEPAs need to be considered in the differential diagnosis of parasellar lesions.

Ectopic pituitary adenomas: clinical features, diagnostic challenges and management

PURPOSE

Ectopic pituitary adenomas (EPAs) are extremely rare pituitary adenomas located outside the sella turcica without any connection with intrasellar components. This study aims to review all the reported cases to date and describe the clinical characteristics of EPAs.

METHODS

In a retrospective chart review, 14 patients were identified with EPAs in our hospital. A literature review was performed, and 166 cases in the literature met the criteria. Clinical data were analyzed.

RESULTS

Of 180 patients with EPAs, the mean age at diagnosis was 45.4 years, and 66.5% of the patients were females. EPAs were mainly located in the sphenoid sinus (34.4%) and suprasellar region (25.6%), followed by the clivus (15.6%), cavernous sinus (13.3%) and nasopharynx (5.6%). Adrenocorticotropic hormone (ACTH)-secreting (38.9%) and nonfunctioning (27.2%) adenomas were predominant. Patients with suprasellar EPAs were more likely to present menstrual disorders and visual changes, while patients with clival EPAs were more likely to suffer from headaches. EPAs in the cavernous sinus and suprasellar space were more likely to be initially misdiagnosed as a suspicious intrasellar mass on imaging examination. The complete tumor resection rates for EPAs in the sphenoid sinus, suprasellar region, clivus, cavernous sinus and nasopharynx were 72.3%, 88.6%, 45.0%, 73.3% and 88.9%, respectively.

CONCLUSIONS

EPA clinical characteristics varied across different tumor locations and hormone-secreting types. In addition to comprehensive hormone evaluation and careful review of imaging data, nuclear medicine and surgical biopsy should also be considered when facing differential difficulty. EPA management should be individualized.

Suprasellar pituitary adenomas: a 10-year experience in a single tertiary medical center and a literature review

BACKGROUND

Suprasellar pituitary adenomas (SPAs) are a special type of pituitary adenoma. Although dozens of SPA cases have been reported, the exact definition and the characteristics of SPA have not been exhaustively discussed before.

METHODS

In a retrospective electronic medical records review, 13 patients with SPA were identified in our hospital between January 2010 and December 2019. A literature review was performed by searching the online database PubMed, and 39 cases conformed to the criteria based on the previous literature. Data regarding clinical symptoms, imaging manifestations, surgical information and follow-ups were analyzed.

RESULTS

The mean age at diagnosis of 52 patients with SPA was 36.73 years, and most of the patients were female (61.5%). The most common hormone-secreting subtypes of SPA were nonfunctioning (36.5%) and ACTH-secreting (34.6%) SPA. Macroadenomas (68.9%) were more common than microadenomas (31.1%). The origins of the SPAs included the intrasellar pituitary gland (type I), the subdiaphragmatic (type IIa) and supradiaphragmatic (type IIb) part of the pituitary stalk, and the suprasellar peri-infundibular region (type III). The most common anatomic subtype of SPA was type III, and type IIb was also common. The most common presentations of SPA were visual symptoms, especially for type III SPA. In addition, 64.7% and 73.1% of type IIb and III SPAs, respectively, were suspected to be of suprasellar origin based on presurgical imaging examination. Patients with tumors of suspected suprasellar origin were more likely to receive transcranial surgery (TCS) initially than those with tumors of suspected intrasellar origin (70.6% vs. 22.2%, p = 0.0013). The intact rate for the pituitary stalk after surgery for type II SPA was lower than that for type I and III SPA (52.6% vs. 92.6%, p = 0.0036). More patients with type II SPA experienced postoperative central diabetes insipidus (CDI) than those with type I and III SPA (57.9% vs. 11.1%, p = 0.0011). There was no significant difference in the incidence of postoperative CDI between transsphenoidal surgery (TSS) and TCS (p = 0.1304). Nine patients in our hospital received extended endoscopic TSS; only one experienced tumor recurrence, and no severe complications occurred after surgery.

CONCLUSIONS

SPAs could be defined as pituitary adenomas completely or partially located in the suprasellar region. There were both similarities and differences among the different anatomic subtypes of SPA. For patients who were suspected of having SPAs, visual field tests, pituitary hormone evaluation and MRI were necessary. Because imaging examination is not a reliable method, surgery is the only way to confirm the tumor origin. Extended endoscopic TSS might be a safe and efficient approach to remove these tumors, but more studies are needed to verify this conclusion. For type II SPA, the pituitary stalk should be carefully protected during surgery, and postoperative CDI should be monitored.

Long-term follow-up for ectopic ACTH-secreting pituitary adenoma in a single tertiary medical center and a literature review

BACKGROUND

Ectopic ACTH-secreting pituitary adenoma (EAPA) are a rare cause of Cushing's disease. Due to the lack of consensus and experience in terms of the diagnosis and treatment of EAPAs, preoperative identification and optimal treatment remain challenging.

PURPOSE

To investigate the characteristics of EAPAs and offer some proposals for the diagnosis and management of this uncommon disease, the EAPA patients admitted to our center and all of the EAPA cases reported in the literature were reviewed.

METHODS

In a retrospective electronic medical chart review, 6 patients (0.39%) with EAPAs were identified from 1536 consecutive patients who were admitted to our hospital with a diagnosis of Cushing's syndrome between January 2000 and August 2019. A literature review was performed on the online databases PubMed and EMBASE, and 52 cases conformed to the criteria. The data regarding biochemical tests, imaging examinations and follow-ups were analyzed.

RESULTS

The mean age of patients with EAPAs was 37.7 years old, and an obvious female predominance (3.5: 1) was demonstrated. The most common location of EAPAs was the cavernous sinus (34.5%), followed by the sphenoid sinus (31.0%) and the suprasellar region (20.7%). No significant differences in the biochemical test results were found among tumors in different locations. Except for sex, no risk factors related to remission were found. Although no significant differences among different locations were found, the tumors in the cavernous sinus had a relatively higher rate of invisibility in terms of imaging and a higher non-remission rate than tumors in other locations.

CONCLUSIONS

In patients with negative intrasellar findings, the uncommon disease of EAPA should be considered. Due to the endocrine similarity between intrasellar pituitary corticotrophin adenoma and EAPA, the preoperative identification of EAPA depends on a careful review of the imaging examinations. Locations such as the cavernous sinus, sphenoid sinus and suprasellar region should be considered first. Tumor resection is recommended when the diagnosis is confirmed.

Calcified ectopic TSH-secreting pituitary adenoma mimicking craniopharyngioma: a rare case report and literature review

Among pituitary adenomas, which are relatively common brain tumors, elements of ectopic, thyroid-stimulating hormone (TSH) secretion, and intratumoral calcification are unusual. Here, we present an extremely rare case of a calcified ectopic TSH-secreting pituitary adenoma arising from the pars tuberalis mimicking craniopharyngioma based on neuroimaging findings. To our knowledge, this is the first case report of calcified ectopic TSH-secreting pituitary adenoma without symptoms of excessive thyroid hormone secretion.

'Ectopic' suprasellar type IIa PRL-secreting pituitary adenoma

BACKGROUND

Ectopic pituitary adenomas (EPAs) are rare, and the suprasellar cistern seems to be the most common location. At this time, no detailed original classification, diagnosis, or treatment protocols for suprasellar pituitary adenomas (SPAs) have been described.

CASE DESCRIPTION

A 19-year-old man showed visual disturbances and lack of libido for 3 years, he suffered a sharp decline in vision with only light perception in the last week. Magnetic resonance imaging scans revealed a large suprasellar cystic lesion with a normal pituitary in the sella turcica. Endocrinological findings showed an extremely high prolactin level of 1250 ng/mL. Because of the sharp decline in vision, the patient underwent total removal of the suprasellar lesion using a transfrontal interhemispheric approach. The tumor pedicle originated in the lower pituitary stalk without any connection to the anterior pituitary gland in the sella turcica, while the diaphragma sellae was incomplete. Clinical and endocrinological cure criteria were fulfilled and postoperative pathology confirmed a prolactin-secreting pituitary adenoma.

CONCLUSION

Ectopic suprasellar pituitary adenomas (ESPAs) are extremely rare intracranial extracerebral tumors. SPAs can be classified into three types according to their origin and their relationship with surrounding tissue. Only type III is theoretically a true ectopic, based on previous reports. Thus, ESPAs are uncommon compared to other EPAs. Our case is the first reported case of a type IIa 'E'SPA and the first description of this subtype classification until now. The pars tuberalis may be different from the pars distalis, and each subtype of adenohypophyseal cells may have different migration characteristics, which leads to different proportions of each hormone-secreting subtype in SPAs and EPAs. Transsphenoidal surgery is minimally invasive, but transcranial surgery may remain a universal option for the treatment of suprasellar lesions.

Ectopic Suprasellar Thyrotropin-Secreting Pituitary Adenoma: Case Report and Literature Review

BACKGROUND

Ectopic thyroid-stimulating hormone (TSH)-secreting pituitary adenomas are rare and can often be misdiagnosed as primary hyperthyroidism. We present a case of an ectopic suprasellar TSH-secreting pituitary adenoma. A literature review of previously reported ectopic TSH-secreting and suprasellar pituitary adenomas is included to illustrate the clinical characteristics of this disease entity and the diversity of operative approaches to treating ectopic suprasellar pituitary adenomas.

CASE DESCRIPTION

A 46-year-old man presented with typical clinical signs of hyperthyroidism and a history of progressive visual field impairment and vision loss. Laboratory investigations revealed that the patient had elevated levels of free thyroxine and free triiodothyronine and a normal level of TSH. Neuro-ophthalmologic examination showed right eye/left eye = 1.0/0.6 and left temporal hemianopia. Magnetic resonance imaging revealed a mass located in the suprasellar space. The patient underwent preoperative short-term octreotide treatment followed by gross total resection of the tumor via the extended endoscopic endonasal transtuberculum sellar approach. At 6-month follow-up evaluation, the patient's endocrinologic function tests met the criteria for cure, and magnetic resonance imaging revealed a normal pituitary gland and stalk with no tumor recurrence. Histologic diagnosis confirmed the presence of a TSH-secreting pituitary adenoma.

CONCLUSIONS

To the best of our knowledge, this is the first reported case of an ectopic suprasellar TSH-secreting pituitary adenoma. Preoperative preparation and complete resection are the keys to a cure. The extended endoscopic endonasal transtuberculum sellar approach is an alternative minimally invasive method for the removal of an ectopic suprasellar pituitary adenoma.

Ectopic ACTH-secreting pituitary adenoma of the sphenoid sinus: case report of endoscopic endonasal resection and systematic review of the literature

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.

Supra-diaphragmatic pituitary adenoma removed through the trans-tuberculum sellae approach. Case report

A 59-year-old woman presented with a rare supra-diaphragmatic pituitary adenoma manifesting as a mass lesion. Her baseline data and the response of anterior pituitary hormones to the provocation test were within the normal range. Magnetic resonance imaging showed a homogeneously enhanced tumor located on the diaphragma sellae. The tumor was totally removed by the endonasal trans-tuberculum sellae approach under combined microscopic and endoscopic observation. Her postoperative course was uneventful and the histological diagnosis was pituitary adenoma located in the suprasellar region. The trans-tuberculum sellae approach is a less invasive method to remove pituitary adenoma located in the suprasellar region.

Ectopic pituitary adenoma presenting as midline nasopharyngeal mass

INTRODUCTION

Ectopic pituitary adenomas are extremely rare. We report a case of ectopic pituitary adenoma in the midline of the nasopharynx. This adenoma probably arose from the pharyngeal remnant of Rathke's pouch.

METHODS

We discuss a case of a lady who presented to our unit with 2 months history of dryness and sensation of lump in her throat and a long standing history of hypothyroidism. Examination of nasopharynx revealed a smooth and fluctuant midline mass. CT scan of nose and paranasal sinuses confirmed the midline mass with small defect communicating with the sphenoid sinus. An initial diagnosis of Thornwaldt's cyst was made and she underwent upper aerodigestive tract endoscopy and marsupialization of the mass. Histopathological examination revealed ectopic pituitary adenoma.

CONCLUSION

Ectopic pituitary adenoma is an important differential diagnosis for a midline nasopharyngeal mass. It is recommended that prior to surgical resection of midline nasopharyngeal mass biopsy is taken and MRI is performed.

Management of ACTH-secreting supradiaphragmatic adenomas

Supradiaphragmatic adrenocorticotropic hormone (ACTH) secreting pituitary adenomas are exceptionally encountered (14 cases previously described) and raise issues concerning their nosology and management. If surgery is the treatment of choice, the nature of surgical approach (craniotomy, transsphenoidal approach) remains controversial. To illustrate this issue, we presented two cases of supradiaphragmatic ACTH secreting pituitary adenomas successfully excised via a subfrontal approach. Both patients were female (20 and 41 years) and had a typical Cushing's syndrome. MRI revealed, in both cases, a suprasellar mass in contact with the pars tuberalis of the pituitary. In the first case, the patient underwent initially a transsphenoidal approach with negative exploration and subsequent partial hypophysectomy. One year later, the patient was operated on again via a subfrontal approach, allowing excision of a supradiaphragmatic adenoma and a complete cure of Cushing's disease. In the second case, the patient underwent initially a subfrontal approach and was definitely cured. In both cases, the diaphragma sellae was found to be intact and the pituitary stalk could be preserved. Postoperative MRI demonstrated a clearly visible intact pituitary stalk in conjunction with normal aspect of the pituitary. Supradiaphragmatic pituitary adenomas are most likely adenomas of the pituitary stalk with extra-axial development. Surgery remains the treatment of choice. Should the superior approach be preferred, the transsphenoidal-transtuberculum sellae approach may represent a viable alternative when performed by a well-trained surgical team. Surgery may be difficult, and drawbacks are non negligible, particularly in elderly patients. In these cases, stereotactic radiosurgery should receive more consideration.

An aberrant ACTH-producing ectopic pituitary adenoma in the sphenoid sinus

A 32-year-old woman with an ectopic adrenocorticotropic hormone (ACTH)-secreting pituitary adenoma (EAPA) is presented. She had rapidly gained weight and suffered recurrent facial acne for a few years but lacked the typical Cushingoid features. Endocrine examinations revealed that her plasma ACTH was markedly high (196 to 280 pg/ml) without showing normal circadian rhythm and failed to respond to corticotropin-releasing hormone stimulation. Her cortisol levels ranged from 22 to 30 microg/dl throughout observation but low doses (1 and 2 mg) of dexamethasone failed to suppress either ACTH or cortisol level. Magnetic resonance imaging study revealed a 3-cm mass occupying the sphenoidal sinus with partial enhancement by gadolinium, which was separated from the normal pituitary in the sella region. The tumor resected by transsphenoidal surgery was histologically diagnosed as an ACTH-producing pituitary adenoma. After surgery her weight gain and acne remitted in accordance with decreases in plasma ACTH. Analysis of patient plasma by gel filtration method revealed the existence of big ACTH molecules eluted with a peak of authentic 1-39 ACTH, suggesting that this biologically less-active ACTH might be the reason why overt features of Cushing's syndrome failed to develop in this case. Although EAPA is clinically rare in parasellar disorders, the presence of ectopic pituitary adenoma should be considered in such cases showing ACTH hypersecretion without typical Cushingoid features.

Ectopic Growth Hormone-Releasing Adenoma in the Cavernous Sinus-Case Report-

A 55-year-old woman presented a rare ectopic pituitary adenoma in the right cavernous sinus manifesting as acromegaly. The tumor was removed via transsphenoidal approach. Intraoperative observation showed the adenoma was located entirely within the right cavernous sinus, and separated from the normal pituitary gland by the medial wall of the cavernous sinus. There was no communication between the tumor and the pituitary. Histological examination showed a growth hormone-releasing adenoma. Including our case, only eight of 86 reported ectopic adenomas have occurred in the cavernous sinus. Such ectopic presentation may be responsible for failed transsphenoidal surgery for endocrinologically active tumors.

Ectopic intracavernous sinus adrenocorticotropic hormone-secreting microadenoma: could this be a common cause of failed transsphenoidal surgery in Cushing disease? Case report

Despite diagnostic advances, it remains difficult to identify intrasellar and ectopic parasellar adrenocorticotropic hormone (ACTH)-secreting microadenomas. The authors present the case of a 61-year-old woman with Cushing disease in whom a significant central-to-peripheral and lateralized right-sided ACTH gradient was demonstrated on inferior petrosal sinus sampling; no discernible abnormality was seen on magnetic resonance imaging. She underwent transnasal transsphenoidal surgery. No tumor was found on sellar exploration and a total hypophysectomy was performed, yet her hypercortisolemia persisted. The patient died of cardiac events 17 days postsurgery. Autopsy revealed an isolated, right-sided, intracavernous ACTH-secreting adenoma with no intrasellar communication. This case represents the first failed transsphenoidal surgery for Cushing disease in which there is postmortem confirmation of a suspected intracavernous sinus lesion. It supports the hypothesis that Cushing disease associated with nondiagnostic imaging studies, a strong ACTH gradient on venography, and negative findings on sellar exploration may be caused by an ectopic intracavernous ACTH-secreting adenoma. There are no premortem means of confirming the presence of such lesions, but these tumors could underlie similar cases of failed surgery. Radiation therapy targeting the sella turcica and both cavernous sinuses, possibly supplemented with medical treatment, is suggested for similar patients in whom transsphenoidal hypophysectomy has failed. Adrenalectomy may also be appropriate if a rapid reduction in ACTH is necessary.

Juxtaposition of an ectopic corticotroph adenoma of the sphenoid sinus with orthotopic intrasellar corticotroph hyperplasia in a patient with Cushing disease. Case report

Ectopic pituitary adenomas (EPAs) are rare and their association with orthotopic corticotroph hyperplasia has not been published. The case of a 30-year-old woman with clinical and biochemical evidence of Cushing disease (CD) is reported. A magnetic resonance image obtained preoperatively revealed asymmetrical inhomogeneity of the pituitary gland, which was suggestive of localized adenoma. It also showed what was thought to be a small sphenoid polyp. Postoperatively the latter lesion was found to be an ectopic corticotroph adenoma. The pituitary gland, which was free from any tumor, exhibited diffuse unilateral corticotroph hyperplasia. Clinical, radiological, laboratory, and histopathological findings are presented. A review of the literature and a discussion of possible causes of this unique association between the ectopic corticotroph adenoma and the pituitary hyperplasia are provided.

Ectopic pro-opiomelanocortin syndrome

Ectopic POMC syndrome remains one of the most challenging differential diagnoses in endocrinology. Recent progress in the understanding of the tissue specific regulation of POMC gene expression and new insights into the processing of the POMC peptide in nonpituitary tissues has helped elucidate some of the molecular events leading to ectopic expression and secretion of POMC peptides. Corticotropin and other POMC-derived peptides have diverse effects on adrenal steroidogenesis, growth, and extra-adrenal tissues. Differences in POMC gene regulation in the corticotrope versus ectopic POMC-producing tumors provides a scientific framework for the clinical distinction between eutopic and ectopic Cushing's syndrome. In an attempt to revisit recent basic and clinical advances in the diagnosis of ectopic POMC syndrome the authors undertook an extensive literature review of 530 cases in 197 published papers and provided a molecular biologic, demographic and diagnostic update. According to this review, the four most common causes of ectopic POMC syndrome are the small cell carcinoma of the lung (27%), bronchial carcinoids (21%), islet cell tumor of the pancreas (16%), and thymic carcinoids (10%). Although the clinical features of patients with ectopic POMC syndrome are similar to those with Cushing's disease, subgroup analysis reveals a broad spectrum of severity and progression of signs and symptoms of hypercortisolism. The endocrine workup of a patient with suspected ectopic POMC syndrome includes the establishment of pathologic hypercortisolism, diagnosis of corticotropin dependency, and the differential diagnosis of corticotropin-dependent Cushing's syndrome. The use of a variety of baseline endocrine values, dynamic endocrine testing, and invasive procedures leads to the correct diagnosis in the majority of patients with ectopic POMC syndrome. Diagnostic imaging, including conventional radiological techniques and somatostatin receptor scintigraphy, aids in the correct localization and eventual treatment of ectopic POMC production.

Diagnosis and differential diagnosis of Cushing's syndrome

The clinical recognition of Cushing's syndrome and its biochemical confirmation is a challenging problem. The best diagnostic approach to patients with suspected Cushing's syndrome is still evolving. The traditional diagnostic approach of urine free cortisol and low-dose dexamethasone suppression testing may be inadequate when the degree of hypercortisolism is mild. Late-night salivary cortisol determinations may evolve as the simplest means of screening patients for suspected hypercortisolism. Repeated measurements of cortisol secretion (urine free cortisol or late-night salivary cortisol) over an extended period of time may be necessary to provide diagnostic certainty. The dexamethasone-CRH test is a reasonable approach in patients with equivocal data. The introduction of reliable, sensitive, and specific plasma ACTH measurements, the use of IPSS for ACTH with CRH stimulation, and the improved techniques of pituitary and adrenal imaging have made the differential diagnosis of Cushing's syndrome relatively straightforward (see Fig. 2). Clinicians who have never missed the diagnosis of Cushing's syndrome or have never been fooled by attempting to establish its cause should refer their patients with suspected hypercortisolism to someone who has.