A case of insulinoma effectively treated with low-dose diazoxide.

Diazoxide is a benzothiadiazine that can be effective in managing hypoglycemia in frail patients with surgical risk. We report here a case of insulinoma effectively treated with diazoxide, as our report will be helpful for similar cases.

Glucocorticoid Receptor Antagonist Administration Prevents Adrenal Gland Atrophy in an ACTH-Independent Cushing's Syndrome Rat Model.

ACTH-independent Cushing's syndrome (CS) is mainly caused by cortisol-secreting adrenocortical tumours. It is well known that secondary adrenal insufficiency occurs after surgical resection of these tumours. In this regard, impaired adrenocortical function is likely induced by atrophy of the residual adrenal tissue as a result of chronic suppression by the low ACTH levels of the hypercortisolism state. Therefore, we considered the prevention of adrenal atrophy as a method for preventing postoperative adrenal insufficiency. On the basis of these findings, we hypothesized that the use of a glucocorticoid receptor (GR) antagonist before surgery in ACTH-independent CS would rapidly activate the hypothalamic-pituitary-adrenal (HPA) axis and residual adrenal function. We thus examined adrenal function in a dexamethasone- (DEX-) induced CS rat model with or without mifepristone (MIF). In this study, MIF-treated rats had elevated plasma ACTH levels and increased adrenal weights. In addition, we confirmed that there were fewer atrophic changes, as measured by the pathological findings and mRNA expression levels of corticosterone synthase CYP11B1 in the adrenal glands, in MIF-treated rats. These results indicate that MIF treatment prevents the suppression of the HPA axis and the atrophy of the residual adrenal tissue. Therefore, our study suggests that preoperative GR antagonist administration may improve residual adrenal function and prevent postoperative adrenal insufficiency in ACTH-independent CS.

Secondary Adrenal Insufficiency Following Nivolumab Therapy in a Patient with Metastatic Renal Cell Carcinoma.

Currently, nivolumab (an anti-programmed cell death-1 receptor monoclonal antibody) is available for many types of advanced cancers in Japan. However, there have been few detailed case reports about endocrine-related adverse events of this therapy. Here, we report a patient with metastatic renal cell carcinoma who presented with secondary adrenal insufficiency following nivolumab therapy. Endocrinological assessment by rapid adrenocorticotropic hormone (ACTH) and corticotropin-releasing hormone (CRH) tests revealed that the patient's disorder was a secondary adrenal insufficiency due to pituitary dysfunction. Moreover, the results of the thyrotropin-releasing hormone (TRH), luteinizing hormone-releasing hormone (LH-RH) and growth hormone-releasing peptide-2 (GHRP-2) tests showed that only the ACTH function was destroyed (isolated ACTH deficiency). The magnetic resonance imaging (MRI) findings of hypophysitis, which is the major cause of isolated ACTH deficiency, usually demonstrate enlargement of the pituitary gland. However, the MRI findings of our case showed no abnormalities of the pituitary gland and stalk. Therefore, not only oncologists, but also other specialists, including doctors in emergency units, should have knowledge of this specific feature. Our clinical observation could be useful to avoid a delay in diagnosis and to treat life-threatening adverse effects of nivolumab therapy, such as secondary adrenal insufficiency.

A Rare Case of Subclinical Primary Aldosteronism and Subclinical Cushing's Syndrome without Cardiovascular Complications.

We report a rare case of subclinical primary aldosteronism (PA) and subclinical Cushing's syndrome (CS). A 49-year-old woman was referred to our hospital for the evaluation of an adrenal incidentaloma. The patient had no previous medical history and no family history of notable illness. Her blood pressure was 103/60 mmHg. She had no Cushingoid features. Routine laboratory examinations were within the normal ranges including normokalemia. Based on the endocrinological results and imaging findings, we finally made a diagnosis of subclinical PA caused by both adrenal glands and subclinical CS caused by bilateral adrenal tumors. Interestingly, this patient had no risk factors for cardiovascular disease. In addition, the optimal management of patients with subclinical CS and subclinical PA has not been established. Therefore, we are observing her without medical therapy. Four years after diagnosis, no cardiovascular complications have been detected, including cerebral infarction, chronic kidney disease, cardiomegaly on echocardiography, and atherosclerosis on carotid ultrasonography. One important question is why the excessive hormone secretion did not affect the cardiovascular status of this patient. In this regard, we discuss several possible mechanisms including mineralocorticoid resistance and glucocorticoid sensitivity.

Adrenal Venous Sampling Is Useful for a Definitive Diagnosis in Cushing's Syndrome with Bilateral Adrenal Tumors.

We report three cases of Cushing's syndrome (CS) with bilateral adrenal tumors. When bilateral adrenal tumors are encountered, a differential diagnosis is difficult to make, especially in the case of functioning bilateral adrenocortical adenoma. Adrenal scintigraphy has become a standard technique to determine the laterality of excessive hormone secretion; however, this examination results in bilateral adrenal activity in the functioning bilateral adrenocortical adenoma. Our three patients were diagnosed with adrenocorticotropic hormone (ACTH)-independent CS based on biochemical testing, and an abdominal computed tomography (CT) scan detected bilateral adrenal tumors. Adrenal scintigraphy showed bilateral adrenal activity in all cases. However, adrenal venous sampling (AVS) demonstrated three different hormone-excess patterns (case 1: bilateral cortisol-excess secretions; case 2: unilateral cortisol-excess secretion and bilateral aldosterone-excess secretions; and case 3: bilateral cortisol-excess secretions and bilateral aldosterone-excess secretions). Based on these findings, we could select optimal treatment for each case. Therefore, AVS is useful to obtain a definitive diagnosis and adequate therapy for CS with bilateral adrenal tumors.