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The endocrine system
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
Adrenocortical tumours arise from the epithelial cells of the adrenal cortex. Broadly, they may be benign adenomas or malignant tumours although it is commonly difficult to distinguish between these two groups. Adenomas are common, affecting 10% of the population. They usually present as a unilateral mass, sometimes incidentally discovered on imaging, and commonly are associated with hormonal secretion. Adenomas may be non-functioning or secrete aldosterone, cortisol, or sex hormones. Macroscopically adenomas are well circumscribed tan, yellow, or rarely black-coloured masses confined to the adrenal glands. Microscopically the sheets of lipid-rich cells resembling the layer of adrenal cortex they originated from (Figure 18.30). The lesional cells may show oncocytic change. Several genes are associated with adenoma formation with genes coding for plasma membrane potassium or calcium channels implicated in aldosterone secreting adenomas (KCNJ5 and ATP1A1). Cortisol secretin adenomas show gain of function mutations in PRKACA. Nonfunctioning adenomas may have CTNNB1 mutations affecting beta-catenin and the WNT pathway.
The adrenal glands and other abdominal endocrine disorders
Published in Professor Sir Norman Williams, Professor P. Ronan O’Connell, Professor Andrew W. McCaskie, Bailey & Love's Short Practice of Surgery, 2018
Professor Sir Norman Williams, Professor P. Ronan O’Connell, Professor Andrew W. McCaskie
The most frequent cause of PHA with hypokalaemia is a unilateral adrenocortical adenoma (Figure 52.3). In 20-40% of cases, bilateral micronodular hyperplasia is present. Rare causes of PHA are bilateral macronodular hyperplasia, glu- cocorticoid-suppressible hyperaldosteronism or adrenocortical carcinoma. In the subset of patients with normokalaemic PHA, 70% have hyperplasia and 30% unilateral adenoma. Somatic mutations at the KCNJ5 gene coding for the potassium channel Kir3.4 are present in aldosterone-producing adenomas and a germline KCNJ5 mutation can cause a very rare autosomal dominant and early-onset form of PHA, characterized by bilateral adrenal hyperplasia.
Surgical pathology of the adrenal gland
Published in Demetrius Pertsemlidis, William B. Inabnet III, Michel Gagner, Endocrine Surgery, 2017
Conn syndrome is a unilateral lesion (adenoma). Upon excision, aldosterone-producing adenomas appear as well-circumscribed bright “canary yellow” masses, usually less than 3 cm in size (Figure 26.17). Many glands removed for a presumed adenoma in fact contain multiple hyperplastic cortical nodules, making a subtotal adrenalectomy a suboptimal treatment option [11]. Somatic mutations in KCNJ5, a potassium channel gene, or others related to calcium transport, are commonly found in aldosterone-producing adenomas and have been identified in these multinodular glands, typically within the dominant nodule [12]. Histologically, adenomas or hyperplastic nodules may be arranged in short cords or nests, resembling the zona glomerulosa, but more often show a zonal pattern with a central area of large steroid lipid cells surrounded peripherally by eosinophilic compact cells (Figures 26.18 and 26.19). Laminated eosinophilic inclusions (spironolactone bodies) may be seen within the cytoplasm of tumor cells.
Macrolides for KCNJ5–mutated aldosterone-producing adenoma (MAPA): design of a study for personalized diagnosis of primary aldosteronism
Published in Blood Pressure, 2018
Giuseppe Maiolino, Giulio Ceolotto, Michele Battistel, Giulio Barbiero, Maurizio Cesari, Laurence Amar, Brasilina Caroccia, Roberto Padrini, Michel Azizi, Gian Paolo Rossi
KCNJ5 mutations cause a loss of the K+ selectivity of the Kir3.4 channel rendering the channel permeable to sodium with increased sodium influx into the APA cells leading to their depolarization, and thereby to opening of the T-type calcium channels and activation in the reverse mode, e.g. Na+ out and Ca2+ in, of the Na+ -Ca2+ exchanger [10]. The ensuing increase of cytosolic Ca2+, and thereby of mitochondria Ca2+, activates the step-limiting enzyme for aldosterone synthesis, e.g. the mitochondrial Ca2+-sensitive aldosterone synthase (CYP11B2), with the final result of a marked activation of aldosterone synthesis.
Prevalence of primary aldosteronism without hypertension in the general population: Results in Shika study
Published in Clinical and Experimental Hypertension, 2018
Shigehiro Karashima, Mitsuhiro Kometani, Hiromasa Tsujiguchi, Hiroki Asakura, Shigeru Nakano, Mikiya Usukura, Shunsuke Mori, Masashi Ohe, Toshitaka Sawamura, Rika Okuda, Akinori Hara, Toshinari Takamura, Masakazu Yamagishi, Hiroyuki Nakamura, Yoshiyu Takeda, Takashi Yoneda
Our data may indicate that sex difference was related to the prevalence of PA in the normal population. Indeed, 77% of previously reported that normotensive PA subjects were women. The average APCC scores in normal adrenal, which were based on frequency and size, were described greater in women than men (27). Somatic mutation of KCNJ5 gene coding for the Kir 3.4 K+ channel, which is one of the causes for APA (28), Lenzini et al. (29) meta-analyzed thirteen studies comprising 1636 APA patients, detected a significant association of KCNJ5 mutations with female gender.