• adrenocortical carcinoma
• Cushing’s syndrome

A 46 year old woman presented with a short history of hirsutism, facial plethora, amenorrhoea, progressive weight gain, and hypertension. Cushing’s syndrome was suspected and confirmed biochemically. Urine free cortisol concentrations measured as cortisol/creatinine ratios on two successive 24 hour urine collections were raised at 80 and 169 nmol/mmol respectively (reference range 5–55).

High dose dexamethasone suppression test was done (dexamethasone 2 mg orally every six hours for 48 hours). Basal serum cortisol was 599 nmol/l and failed to suppress after 48 hours, remaining raised at 555 nmol/l. This was suggestive of primary adrenal disease as cortisol levels normally suppress to less than 50% of basal levels in pituitary driven Cushing’s disease. Serum testosterone was raised at 7.2 nmol/l (0.5–2.6). Urinary catecholamine levels were normal. The short history and raised testosterone level was suggestive of an adrenal carcinoma. Abdominal computed tomography showed a large left adrenal tumour with central necrosis and no evidence of metastases (see fig 1). An adrenal carcinoma was subsequently completely resected.

Primary adrenal tumours are responsible for about 10% of cases of Cushing’s syndrome. Adrenocortical carcinomas are uncommon with an incidence of 2 per million per year and occur more commonly in women. Raised androgen levels in Cushing’s syndrome are suggestive of malignant adrenal tumours.

Adrenal carcinomas are rapidly progressive and have usually metastasised to the lungs and liver at diagnosis. Mitotane, an isomer of the insecticide DDT, has been used as adjunctive therapy to treat metastatic disease.

Figure 1

Abdominal computed tomography showing left adrenal tumour.