Background: Adrenal incidentaloma (AI) increasingly pose a diagnostic challenge. This retrospective observational study evaluated biochemical investigations performed in patients referred to Endocrine Surgery with AI and assessed adherence to Guidelines. Biochemical, histological and radiological characteristics of AI were also reviewed.
Methods: Data were collected from Hospital and Laboratory records for referrals between January 2012April 2014.
Results: 125 patients were referred (21 excluded; 19 bulky adrenals and two metastases). 104 patients were included, 70 were female, median age 63 years (range 1787).
Review of biochemical investigations showed 90 and 96% of patients had ACTH and cortisol measured following an overnight dexamethasone suppression test (DXMST). Renin, aldosterone and metadrenalines were measured in 80, 88 and 89% of patients, respectively.
Urinary and or plasma metadrenalines were >3 times upper reference range in all patients with phaeochromocytoma. Aldosterone was increased in one patient (n=91). 32 patients (n=97) failed to suppress cortisol following an overnight DXMST and, 23 (n=24) also failed to supress cortisol after a low dose DXMST. AI dimensions were available in 87 patients (22 ≧4 cm). Twenty AI were removed: six phaeochromocytoma; 11 adrenal cortical adenoma (six cortisol secreting); one adrenal myelolipoma; one adrenal ganglioneuroma and one adrenal angiomyolipoma.
Conclusions: The majority of patients referred to our Unit had appropriate biochemical investigations performed. This study reports a similar incidence of phaeochromocytoma (5%) and subclinical Cushings syndrome (7.7%) compared to current literature. In the absence of current UK Guidelines for the investigation of AI, laboratories must work closely with Endocrine Specialists to ensure appropriate biochemical investigations are performed.