Nebennierentumoren

Differentiating Benign from Malignant Adrenocortical Tumors by a Single Morphological Parameter-a Clinicopathological Study on 837 Adrenocortical Neoplasias

The morphological differentiation between benign and malignant adrenocortical tumors is an ongoing problem in diagnostic pathology. In recent decades the complex scoring systems have been widely used to calculate the probability of malignancy in adrenocortical tumors on the basis of a variety of histomorphological parameters. We herewith present a substantially simplified method to diagnose adrenocortical carcinoma by a single histomorphological parameter on a consecutive series of more than 800 adrenocortical tumors. Between January 2000 and May 2019, altogether 2305 adrenalectomies for of all types of diseases were removed, approximately 98% by minimally invasive approaches. After exclusion of pheochromocytomas, adrenal ganglioneuromas, adrenal metastases, Cushing’s disease related specimens, and Conn’s adenomas, the present series finally consisted of 837 adrenocortical tumors. All tumors were analyzed by experienced pathologists of a single institution using standard histopathological methods (Hematoxylin-Eosin and Ki67 stained sections). Clinical and histopathologic data were prospectively collected and retrospectively analyzed. Clinically, 385 patients had 420 functioning tumors (FT), and 417 had non-functioning adrenal tumors (NFT). The mean size of FT was 3.8 ± 1.4 cm (range 0.5–16 cm) and for NFT 4.5 ± 1.6 cm (range 1.5–18 cm). Histomorphologically, 32 adrenal tumors were classified as adrenocortical carcinoma (ACC; 3.8%). In all 32 cases (tumor size 9.1 ± 4.0 cm, range 3–18 cm), confluenting tumor necrosis could be demonstrated. The remaining 805 tumors (control group) completely lacked this highly reproducible single morphological feature. Ki67 levels above 10% were found in 31 of 32 ACCs and never in adrenocortical adenomas (ACA). With a mean follow-up of 8.2 years, 24 out of 32 patients primarily diagnosed as ACC developed distant metastases (75.0%), whereas all patients in the control group remained free of local or distant recurrence. We conclude that a single morphological parameter (confluenting tumor necrosis) is sufficient to predict a poor clinical course in adrenocortical tumors. The histomorphological diagnosis of this parameter is straightforward and highly reproducible.

Aldosterone-producing adenoma and other surgically correctable forms of primary aldosteronism

Surgically correctable forms of primary aldosteronism are characterized by unilateral aldosterone hypersecretion and renin suppression, associated with varying degrees of hypertension and hypokalemia. Unilateral aldosterone hypersecretion is caused by an aldosterone-producing adenoma (also known as Conn's adenoma and aldosteronoma), primary unilateral adrenal hyperplasia and rare cases of aldosterone-producing adrenocortical carcinoma. In these forms, unilateral adrenalectomy can cure aldosterone excess and hypokalemia, but not necessarily hypertension. The prevalence of primary aldosteronism in the general population is not known. Its prevalence in referred hypertensive populations is estimated to be between 6 and 13%, of which 1.5 to 5% have an aldosterone-producing adenoma or primary unilateral adrenal hyperplasia. Taking into account referral biases, the prevalence of surgically correctable primary aldosteronism is probably less than 1.5% in the hypertensive population and less than 0.3% in the general adult population. Surgically correctable primary aldosteronism is sought in patients with hypokalemic, severe or resistant forms of hypertension. Recent recommendations suggest screening for primary aldosteronism using the aldosterone to renin ratio. Patients with a raised ratio then undergo confirmatory suppression tests. The differential diagnosis of hypokalemic hypertension with low renin includes mineralocorticoid excess, with the mineralocorticoid being cortisol or 11-deoxycorticosterone, apparent mineralocorticoid excess, pseudo-hypermineralocorticoidism in Liddle syndrome or exposure to glycyrrhizic acid. Once the diagnosis is confirmed, adrenal computed tomography is performed for all patients. If surgery is considered, taking into consideration the clinical context and the desire of the patient, adrenal vein sampling is performed to detect whether or not aldosterone hypersecretion is unilateral. Laparoscopic surgery for unilateral aldosterone hypersecretion is associated with a morbidity of about 8%, with most complications being minor. It generally results in the normalization of aldosterone secretion and kalemia, and in a large decrease in blood pressure, but normotension without treatment is only achieved in half of all cases. Normotension following adrenalectomy is more frequent in young patients with recent hypertension than in patients with long-standing hypertension or a family history of hypertension.