Functional disorders of the adrenal glands: an overview

Adrenal C11-oxy C21 steroids contribute to the C11-oxy C19 steroid pool via the backdoor pathway in the biosynthesis and metabolism of 21-deoxycortisol and 21-deoxycortisone

21-Hydroxylase deficiency presents with increased levels of cytochrome P450 21-hydroxylase substrates, progesterone and 17α-hydroxyprogesterone, which have been implicated in the production of androgens via the backdoor pathway. This study shows the biosynthesis of C11-oxy C₂₁ steroids, 21-deoxycortisol and 21-deoxycortisone, and their metabolism by steroidogenic enzymes in the backdoor pathway yielding novel steroid metabolites: 5α-pregnan-11β,17α-diol-3,20-dione; 5α-pregnan-17α-ol-3,11,20-trione; 5α-pregnan-3α,11β,17α-triol-20-one and 5α-pregnan-3α,17α-diol-11,20-dione. The metabolism of 21-deoxycortisol was validated in LNCaP cells expressing the relevant steroidogenic enzymes showing for the first time that the steroid, produced at high levels in 21OHD, is metabolised via the C11-oxy derivatives of 5α-pregnan-17α-ol-3,20-dione and 5α-pregnan-3α,17α-diol-20-one to substrates for the lyase activity of CYP17A1, leading to the production of C11-oxy C₁₉ steroids. 21-Deoxycortisol thus contributes to the pool of potent androgens in 21OHD, with novel steroid metabolites also presenting possible biomarkers in disease identification.

CT and MR imaging of unusual locations of extra-adrenal paragangliomas (pheochromocytomas)

Our review was undertaken to describe CT and MRI features of unusual extra-adrenal paragangliomas (pheochromocytomas). We retrospectively reviewed CT and MRI findings in 29 patients with 39 extra-adrenal paragangliomas. For each tumour, site, size, MRI characteristics, CT appearances and enhancement after gadolinium and iohexol were recorded. There were 17 carotid body tumours, 1 mediastinal, 1 intra-cardiac, 15 retroperitoneal extra-adrenal paragangliomas, 2 bladder, 1 pelvic sidewall and 2 intra-spinal paragangliomas within the lumbo-sacral spine. All 39 paragangliomas were shown on MRI. Of the 32 lesions studied by MRI and CT, CT detected 30. Of the two lesions missed on CT, one was an intra-cardiac paraganglioma and the second a bladder wall paraganglioma. At detection, 25 tumours were larger than 4 cm, of which 20 were heterogeneous lesions on CT and MRI with variable contrast enhancement. The 14 smaller paragangliomas were smooth in contour and demonstrated avid, homogeneous contrast enhancement. Our review of extra-adrenal paragangliomas highlights their unusual sites and appearances. MRI demonstrated the greatest variability in the appearances of larger tumours, provided additional information compared to CT for surgical planning and is a useful screening tool for patients at high risk of extra-adrenal paragangliomas.

Magnetic resonance: evaluation of adrenal lesions

Magnetic resonance imaging provides a detailed display of adrenal anatomy. The development of new imaging sequences, especially chemical shift imaging, has vastly enhanced the specificity of magnetic resonance imaging. This review outlines current magnetic resonance imaging strategies for assessing disease affecting the adrenal glands. Particular emphasis is placed on the characterization of adrenal masses.