Mutations in the gene encoding the protein kinase A (PKA) catalytic subunit α have been found to be responsible for cortisol-producing adenomas (CPAs). In this study, we identified by whole-exome sequencing the somatic mutation p.S54L in the PRKACB gene, encoding the catalytic subunit β (Cβ) of PKA, in a CPA from a patient with severe Cushing syndrome. Bioluminescence resonance energy transfer and surface plasmon resonance assays revealed that the mutation hampers formation of type I holoenzymes and that these holoenzymes were highly sensitive to cAMP. PKA activity, measured both in cell lysates and with recombinant proteins, based on phosphorylation of a synthetic substrate, was higher under basal conditions for the mutant enzyme compared with the WT, while maximal activity was lower. These data suggest that at baseline the PRKACB p.S54L mutant drove the adenoma cells to higher cAMP signaling activity, probably contributing to their autonomous growth. Although the role of PRKACB in tumorigenesis has been suggested, we demonstrated for the first time to our knowledge that a PRKACB mutation can lead to an adrenal tumor. Moreover, this observation describes another mechanism of PKA pathway activation in CPAs and highlights the particular role of residue Ser54 for the function of PKA.

Context Germline CDKN1B variants predispose patients to multiple endocrine neoplasia type 4 (MEN4), a rare MEN1-like syndrome, with <100 reported cases since its discovery in 2006. Although CDKN1B mutations are frequently suggested to explain cases of genetically-negative MEN1, the prevalence and phenotype of MEN4 patients is poorly known, and genetic counseling is unclear. Objective To evaluate the prevalence of MEN4 in MEN1-suspected patients and characterize the phenotype of MEN4 patients. Design Retrospective observational nationwide study. Narrative review of literature and variant class reassessment. Patients We included all adult patients with class 3/4/5 CDKN1B variants identified by the laboratories from the French TENGEN network between 2015 and 2022 through germline genetic testing for MEN1 suspicion. After class reassessment, we compared the phenotype of symptomatic patients with class 4/5 CDKN1B variants, i.e. with genetically-confirmed MEN4 diagnosis, in our series and in literature with 66 matched MEN1 patients from the UMD-MEN1 database. Results From 5600 MEN1-suspected patients analyzed, four patients with class 4/5 CDKN1B variant were found (0.07%). They presented with multiple duodenal NET, PHPT and adrenal nodule, isolated PHPT, PHPT and pNET. We listed 29 patients with CDKN1B class 4/5 variants from literature. Compared to matched MEN1 patients, MEN4 patients presented lower NET incidence and older age at PHPT diagnosis. Conclusion The prevalence of MEN4 is low. PHPT and PA represent the main associated lesions, NETs are rare. Our results suggest a milder and later phenotype than in MEN1. Our observations will help to improve genetic counseling and management of MEN4 families.

Bilateral adrenal hyperplasia is a rare cause of Cushing’s syndrome. Micronodular adrenal hyperplasia, including the primary pigmented micronodular adrenal dysplasia (PPNAD) and the isolated micronodular adrenal hyperplasia (iMAD), can be distinguished from the primary bilateral macronodular adrenal hyperplasia (PBMAH) according to the size of the nodules. They both lead to overt or subclinical CS. In the latter case, PPNAD is usually diagnosed after a systematic screening in patients presenting with Carney complex, while for PBMAH, the diagnosis is often incidental on imaging. Identification of causal genes and genetic counseling also help in the diagnoses. This review discusses the last decades’ findings on genetic and molecular causes of bilateral adrenal hyperplasia, including the several mechanisms altering the PKA pathway, the recent discovery of ARMC5, and the role of the adrenal paracrine regulation. Finally, the treatment of bilateral adrenal hyperplasia will be discussed, focusing on current data on unilateral adrenalectomy.

Over the past decade, transaxillary robot-assisted thyroidectomy (TRAT) has played a growing role in the management of thyroid nodules. Despite thousands of patients being operated on in Asia for a long time, a few cases of subcutaneous thyroid tissue (STI) have recently been described in the literature, relating to new palpable mass being discovered several years after the original endoscopic thyroidectomy surgery. The high dose radioiodine therapy performed in two patients of a series of 19 patients allowed us to discover precociously microscopic SIT. STI after TRAT could be more common than it currently is, if we consider ectopic tissue uptake with high dose RIT. Despite the use of an endobag for extraction, the dissemination due to thyroid capsule rupture after indelicate robotic manipulation is probably the cause, especially because of the size of the nodules and the lack of experience of beginner surgeons. Hence, until dedicated robotic surgeons acquire a sufficient level of technical experience, and according to the indication of intervention (e.g. thyroid volume), long-term follow-up should be proposed for patients who have not had RIT, in order to reveal if these SITs could lead later to an ectopic thyroid mass and its putative oncologic consequences in the context of thyroid cancer cells dissemination.

Context Oral once-daily dual-release hydrocortisone (DR-HC) replacement therapy has demonstrated an improved metabolic profile compared to conventional 3-times-daily (TID-HC) therapy among patients with primary adrenal insufficiency. This effect might be related to a more physiological cortisol profile, but also to a modified pattern of cortisol metabolism. Objective This work aimed to study cortisol metabolism during DR-HC and TID-HC. Design A randomized, 12-week, crossover study was conducted. Intervention and Participants DC-HC and same daily dose of TID-HC were administered to patients with primary adrenal insufficiency (n = 50) vs healthy individuals (n = 124) as controls. Main Outcome Measures Urinary corticosteroid metabolites were measured by gas chromatography/mass spectrometry at 24-hour urinary collections. Results Total cortisol metabolites decreased during DR-HC compared to TID-HC (P < .001) and reached control values (P = .089). During DR-HC, 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) activity measured by tetrahydrocortisol + 5α-tetrahydrocortisol/tetrahydrocortisone ratio was reduced compared to TID-HC (P < .05), but remained increased vs controls (P < .001). 11β-HSD2 activity measured by urinary free cortisone/free cortisol ratio was decreased with TID-HC vs controls (P < .01) but normalized with DR-HC (P = .358). 5α- and 5β-reduced metabolites were decreased with DR-HC compared to TID-HC. Tetrahydrocortisol/5α-tetrahydrocortisol ratio was increased during both treatments, suggesting increased 5β-reductase activity. Conclusions The urinary cortisol metabolome shows striking abnormalities in patients receiving conventional TID-HC replacement therapy, with increased 11β-HSD1 activity that may account for the unfavorable metabolic phenotype in primary adrenal insufficiency. Its change toward normalization with DR-HC may mediate beneficial metabolic effects. The urinary cortisol metabolome may serve as a tool to assess optimal cortisol replacement therapy.