Spontaneous remission of Cushing's disease: A systematic review

Spontaneous remission is rare in Cushing's disease. We describe one illustrative case and provide a systematic review of cases previously reported in the literature. Case report: A 51-year-old woman diagnosed with Cushing's disease underwent 9 months' isolated metyrapone treatment. Two months after end of treatment, she was admitted with acute kidney failure. After another 4 months, in June 2020, there was no evidence of hypercortisolism, either clinically or biochemically, or of hypocortisolism. At the time of writing, 1 year later, she was still in remission. Cases reported in the literature: 23 patients were reported, including the present case. 87% were female with a median age of 32 years. Ten of those with radiologically visible tumors had microadenoma (44%) and 7 had macroadenoma (30%). Mean time from diagnosis to spontaneous remission was 5 months, and was shorter in macroadenoma (1 month) than in microadenoma (13.5 months). Treatments before spontaneous remission were: no treatment (65%), steroidogenesis enzyme inhibitors (22%), bilateral adrenalectomy and adrenal autotransplantation (5%), partial bilateral adrenalectomy (4%), and incomplete pituitary surgery (4%). Pituitary tumor apoplexy was the most frequently incriminated event (91%), radiologically documented in 43% of patients. Mean remission during follow-up was 28 months (range, 6-130 months). Recurrence occurred in 39% (n=9) of patients. Although several mechanisms responsible for this phenomenon have been proposed, clinical or subclinical pituitary tumor apoplexy, the latter sometimes presenting atypically, seems to be the most frequently incriminated event. Doctors should be aware of this, and regular follow-up is mandatory due to its unpredictability.

Pituitary Adenomas with Changing Phenotype: A Systematic Review

PURPOSE AND METHODS

Phenotype transformation in pituitary adenomas (PA) is a little known and unexpected clinical phenomenon. We describe two illustrative cases and performed a systematic review of cases reported in literature.

RESULTS

Case 1: A 24-year-old woman underwent surgery because of Cushing's disease. A complete tumor resection and hypercortisolism resolution was achieved. Two years later, tumor recurred but clinical and hormonal hypercortisolism were absent. Case 2: A 77-year-old woman underwent surgery due to acromegaly. A complete tumor resection and GH excess remission was achieved. Four years later, tumor recurred but clinical and hormonal acromegaly was ruled out. Search of literature: From 20 patients (including our cases), 75% were female with median age 45 (19) years. Ten patients (50%) had initially functioning PA: 8 switched to NFPA (5 ACTH-secreting PA, 2 prolactinomas and 1 acromegaly) and 2 exchanged to acromegaly from TSH-secreting PA and microprolactinoma. One patient developed a pituitary carcinoma from ACTH-secreting PA. Ten patients (50%) initially had NFPA; 9 developed Cushing's disease (4 silent corticotroph adenomas, 4 null cell PA and 1 managed conservatively). One patient with silent somatotroph PA changed to acromegaly. Treatments before transformation were surgery (80%), radiotherapy (40%), pharmacological (40%) and in 2 patients switching happened without any treatment. Median follow-up until transformation was 72 months (range 12-276).

CONCLUSION

PA can change from functioning to (NF) non-functioning (vice versa) and even exchange their hormonal expression. Clinicians should be aware and a careful lifelong follow-up is mandatory to detect it.

Delayed Diagnosis of Cushing's Disease in a Pediatric Patient due to Apparent Remission from Spontaneous Apoplexy

We report here a pediatric patient whose Cushing's Disease was diagnosed late because of her cyclical presentation, presumably due to subclinical pituitary apoplexy. Starting at age 8, she presented with observable signs of Cushing's but was not clinically assessed for Cushing's Syndrome until the age of 15. Initial tests at age 15 were consistent with Cushing's Disease, however, the patient presented with spontaneous remission of hypercortisolemia just a few short months later. Her cushingoid features never subsided, and at age 17, her MRI showed a partially empty sella; this finding of an empty sella contributed evidence to our suspicion of asymptomatic apoplexy, especially since the patient never reported an episode of acute headache. Pituitary apoplexy in corticotroph adenomas is very uncommon, but even more rare in microadenomas, making this case very unusual. Lost to follow-up, she was not reevaluated for Cushing's Disease until age 25, and her laboratory tests were consistent with an adrenocorticotrophic-dependent pituitary tumor; Pituitary magnetic resonance imaging revealed a 9 mm X 6 mm X 8 mm mass projecting on the superior aspect of pituitary and abutting the wall of the right cavernous sinus. The patient had a transsphenoidal surgery to remove the microadenoma and is planned to undergo radiation therapy. To the best of our knowledge, this is the first report of subclinical apoplexy of a microadenoma in a pediatric patient with Cushing's Disease. It brings to light the importance of long term follow up for pediatric patients presenting with clinical symptoms of Cushing's Syndrome.

Treatment of Cushing's disease: a mechanistic update

Cushing's disease (CD) is characterized by an ACTH-producing anterior corticotrope pituitary adenoma. If hypothalamus-pituitary-adrenal (HPA) axis physiology is disrupted, ACTH secretion increases, which in turn stimulates adrenocortical steroidogenesis and cortisol production. Medical treatment plays an important role for patients with persistent disease after surgery, for those in whom surgery is not feasible, or while awaiting effects of radiation. Multiple drugs, with different mechanisms of action and variable efficacy and tolerability for controlling the deleterious effects of chronic glucocorticoid excess, are available. The molecular basis and clinical data for centrally acting drugs, adrenal steroidogenesis inhibitors, and glucocorticoid receptor antagonists are reviewed, as are potential novel molecules and future possible targets for CD treatment. Although progress has been made in the understanding of specific corticotrope adenoma receptor physiology and recent clinical studies have detected improved effects with a combined medical therapy approach, there is a clear need for a more efficacious and better-tolerated medical therapy for patients with CD. A better understanding of the molecular mechanisms in CD and of HPA axis physiology should advance the development of new drugs in the future.

Prolonged remission after long-term treatment with steroidogenesis inhibitors in Cushing's syndrome caused by ectopic ACTH secretion

Spontaneous remission is rare in ectopic ACTH syndrome (EAS). We describe four patients with presumed EAS in whom long-term treatment with steroidogenesis inhibitors was followed by prolonged remission of hypercortisolemia. Biochemical testing was consistent with EAS, but imaging failed to identify a tumor. Patients were treated with ketoconazole alone or with mitotane and/or metyrapone to control hypercortisolemia. Dexamethasone was added when a block and replace strategy was used. Treatment with steroidogenesis inhibitors for 3-10 years in these patients was followed by a prolonged period of remission (15-60 months). During remission, the first patient had an elevated ACTH, low cortisol and 24-h urinary free cortisol (UFC), and adrenal atrophy on computerized tomography scan during remission, suggesting a direct toxic effect on the adrenal glands. Cases 2 and 3 had normal to low ACTH levels and low-normal UFC, consistent with an effect at the level of the ectopic tumor. They did not have a history of cyclicity and case 3 has been in remission for ~5 years, making cyclic Cushing's syndrome less likely. Case 4, with a history of cyclic hypercortisolism, had normal to slightly elevated ACTH levels and low-normal UFC during remission. The most likely etiology of remission is cyclic production of ACTH by the ectopic tumor. Spontaneous and sustained remission of hypercortisolemia is possible in EAS after long-term treatment with steroidogenesis inhibitors; a drug holiday may be warranted during chronic therapy to evaluate this. The pathophysiology remains unclear but may involve several different mechanisms.

Cyclic Cushing's syndrome: an overview

Cyclic Cushing's syndrome (CS) is a disorder in which glucocorticoid levels are alternately normal and high, the latter occurring in episodes that can last from a few days to several months. It is more common in children than in adults. Cyclic CS may be either of the two different forms of CS (ACTH-dependent or -independent CS). Clinically, it may present with one or many symptoms, depending on the duration of disease activity and the timing of the fluctuations. A serotoninergic influence, cyclic changes in central dopaminergic tone, spontaneous episodic hemorrhage in the tumor, and the action of inflammatory cytokines with antitumor properties are some of the mechanisms suggested to explain the physiopathology of this phenomenon but the exact mechanism remains to be clarified. The cyclic pattern of hypercortisolism can delay the final diagnosis of CS and make it difficult to interpret the results of dynamic tests. Patients may have paradoxical responses to dexamethasone that can reflect increasing or decreasing levels of endogenous activity. Hormone assessments have to be repeated periodically when a diagnosis of CS is suspected. The cyclic pattern can also interfere with medical treatment because patients may show unexpected clinical and biochemical signs of hypocortisolism when cortisol secretion cyclically returns to normal, so an accurate follow-up is mandatory in these patients.

Resolution of Cushing's disease followed by secondary adrenal insufficiency after anticoagulant-associated pituitary hemorrhage: report of a case and review of the literature

OBJECTIVE

To describe the 12th well-documented case of spontaneous resolution of pituitary Cushing's disease due to pituitary hemorrhage and to review data on the previous 11 such patients described in the literature.

METHODS

We present the longitudinal clinical, endocrinologic, and radiographic data in a 41-year-old woman with Cushing's disease before and after pituitary hemorrhage and summarize similar data in 11 previous reports of patients who convincingly appear to demonstrate the same syndrome.

RESULTS

A 41-year-old woman with classic features of Cushing's disease had an overnight dexamethasone suppressed serum cortisol level of 23 mg/dL. Five months later, symptomatic pituitary hemorrhage developed in conjunction with characteristic pituitary magnetic resonance imaging findings and a serum cortisol value of 2.2 mg/dL. During the ensuing 8 months, she lost her Cushing's habitus, demonstrated improvement in her secondary adrenal insufficiency, and developed an empty right sella turcica, which remained unchanged on 1-year follow-up magnetic resonance imaging of the pituitary. An overnight metyrapone test 3 months later yielded normal results.

CONCLUSION

Spontaneous remission in pituitary Cushing's disease, with or without later recurrence, has now been well documented in 12 patients. These findings (1) compel a reassessment of whether previously described patients experiencing spontaneous remission in association with medical therapy may have actually sustained asymptomatic pituitary hemorrhage and (2) raise the question of whether, in selected patents with microadenomas, medical treatment of Cushing's disease should be considered more often.

Cyclic Cushing's disease associated with primary empty sella

A small number of cases of Cushing's disease (CD) associated with primary empty sella (ES) have been described in the literature. Pituitary microsurgery is the recommended treatment. An alternative is chronic treatment with ketoconazole, an inhibitor of adrenal cortisol synthesis. Cyclic Cushing's syndrome is characterized by episodic cortisol hypersecretion. CD is the most frequent etiology of cyclic Cushing's syndrome. To our knowledge, cyclic CD has not previously been reported in association with primary ES. We describe a patient with cyclic CD associated with primary ES who was initially treated with ketoconazole and subsequently cured by transsphenoidal surgery.

Medical therapy for Cushing's disease

Various drugs have been employed in the management of pituitary-dependent Cushing's disease. The neuromodulatory compounds used thus far have demonstrated true clinical efficacy only occasionally when employed as sole treatment. Steroid synthesis inhibitors are effective in the majority of cases in a dose-dependent manner. By their ability to correct hypercortisolism and its severe complications quickly, they are suitable for critical cases and in preparation for surgery. The clinical experience with the only glucocorticoid receptor antagonist that can be administered to humans is still too limited to assess its therapeutic validity. No medical strategy can be standardized for this complex condition. Different therapeutic tools should be selected according to the form of disease to be treated (hypothalamic/pituitary) and the peculiar clinical situation of each patient. Combined treatments may achieve better therapeutic efficacy.