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There are differences in the responsiveness to differential diagnostic tests for Cushing’s disease (CD), corticotroph tumor size, and the somatostatin receptor (SSTR) 5 expression in corticotroph tumors between CD patients. The differences in SSTR5 expression are particularly significant for identifying therapeutic targets for CD. However, prospective predictors of SSTR5 expression remain unclear. Thus, our objective was to elucidate the relationships among these clinical characteristics of CD, including SSTR5 expression. In 27 hospitalized patients with CD at Osaka University Hospital, Osaka, Japan, associations between corticotroph tumor diameter, the response of ACTH and cortisol to differential diagnostic tests for CD (CRH, desmopressin [DDAVP], and high-dose dexamethasone suppression test [HDDST]), the ACTH/cortisol index, and the SSTR5 immunoreactive score were retrospectively investigated. The response to differential diagnostic tests, ACTH/cortisol index, tumor diameter, and SSTR5 expression were significantly related (vs. tumor diameter [CRH: r = –0.54; DDAVP: r = –0.54; HDDST r = –0.67; ACTH/cortisol index: r = 0.76; SSTR5: r = –0.61], vs. CRH [DDAVP: r = 0.63, HDDST: r = 0.72, ACTH/cortisol index: r = –0.45; SSTR5: r = 0.56], vs. DDAVP [HDDST: r = 0.66; ACTH/cortisol index: r = –0.46; SSTR5: r = 0.76], vs. HDDST [ACTH/cortisol index: r = –0.62; SSTR5: r = 0.77], ACTH/cortisol index vs. SSTR5: r = –0.67). The areas under the receiver operating characteristic curve for the prediction of high SSTR5 expression via the CRH test, DDAVP test, HDDST, ACTH/cortisol index, and tumor diameter were 0.79, 0.87, 0.80, 0.71, and 0.71, respectively. Tests for differential diagnosis of CD, the ACTH/cortisol index, and the corticotroph tumor diameter have the potential for identifying SSTR5 expression in corticotroph tumors. These parameters may reflect the biological characteristics of corticotroph tumors.

Aldosterone secretion in primary aldosteronism (PA) is often regulated by adrenocorticotropic hormone (ACTH) in addition to its autonomous secretion. However, the clinical characteristics and risk of cardiovascular and cerebrovascular (CCV) events in PA patients with aldosterone responsiveness to ACTH stimulation remain unclear. This study aimed to investigate the prevalence of CCV events in PA patients with high aldosterone responsiveness to ACTH stimulation. A retrospective cross-sectional study was conducted as part of the Japan Primary Aldosteronism Study/Japan Rare Intractable Adrenal Disease project. PA patients with adrenal venous sampling (AVS) between January 2006 and March 2019 were enrolled. The ACTH-stimulated plasma aldosterone concentration (PAC) of the inferior vena cava during AVS was used to evaluate aldosterone responsiveness to ACTH. We analyzed the relationship between responsiveness and previous CCV events. Logistic regression analysis demonstrated that the ΔPAC (the difference between the PAC measurements before and after ACTH stimulation) significantly increased the odds of previous CCV events in PA patients after adjusting for classical CCV event risk factors, baseline PAC and duration of hypertension (relative PAC: odds ratio [OR], 2.896; 95% confidence interval [CI], 0.989–8.482; ΔPAC: OR, 2.344; 95% CI, 1.149–4.780; ACTH-stimulated PAC: OR, 2.098; 95% CI, 0.694–6.339). This study clearly demonstrated that aldosterone responsiveness to ACTH is closely related to previous CCV events. The responsiveness of the PAC to ACTH could be useful in predicting CCV event risk. Registration Number in UMIN-CTR is UMIN000032525.

Myxedema coma is a rare life-threatening form of hypothyroidism that manifests as neuropsychiatric, metabolic, respiratory, and cardiovascular dysfunction. From 2010 to 2022, our hospital managed three cases of myxedema coma. While the overall characteristics of these cases were similar to those in previous reports, we noticed that all cases were negative for thyroid autoantibodies and an autopsy in one of the cases exhibited end-stage thyroiditis. During a systematic review of cases from 1999 to 2022, we also noticed that a significant proportion of myxedema coma was caused by seronegative primary hypothyroidism especially in Japan.