A rare cause of secondary hypertension.

A 20-year-old obese man was referred to our hospital with 1-year hypertension and mild hypokalaemia (potassium, 3.3 mmol/l). The ratio of postcaptopril plasma aldosterone concentration (PAC) to plasma renin activity (PRA) was high [25.8 (ng/dl)/0.33 (ng/ml/h) = 77.4]. The PAC postsaline loading test remained high (28.1 ng/dl). The 24-h urinary catecholamines and VMA (vanillyl mandelic acid) were within normal limits. Primary aldosteronism was diagnosed, and a computed tomography disclosed an isodense mass with a maximal diameter of 4 cm over the right adrenal gland (Figure 1). The patient then underwent right laparoscopic adrenalectomy. Grossly, a well-encapsulated 4.5 × 4.0 × 3.5 cm yellowish tumour with central necrosis was noted. Histologically, the tumour was composed of pleomorphic cells with high-grade nuclei, prominent nucleoli, and >1/3 of the tumour presenting patternless sheets of cells. Furthermore, the mitotic count was >5 in 50 high power fields with atypical mitotic figures (Figure 2a and b). Adrenocortical carcinoma (ACC) was diagnosed according to the modified Weiss classification system [1]. Subsequent immunohistochemical studies confirmed that the tumour was aldosterone producing (Figure 2c and d). Two months after the operation, PAC and PRA were 32.7 ng/dl and 25.45 ng/ml/h, respectively, and the patient became normotensive.

Fig. 1

Adrenal tumour. Non-contrast CT scan shows an oval tumour, 4 cm in diameter, in the right adrenal region.

Fig. 2

Histopathology of adrenocortical carcinoma. (a) Pleomorphic tumour cells form patternless sheets of cells. (b) Tumour cells with eosinophilic cytoplasm, high nuclear grade and atypical mitotic figures (arrows) (haematoxylin and eosin stain, 100×; 400×). (c) Positive immunohistochemical staining for aldosterone (100×). (d) Substitution of non-immune serum for the primary antibody eliminated the signal as negative control (100×).

ACCs are rare and account for an estimated 0.05–0.2% of all malignancies [2]. Hormonally functioning tumours occur in ∼50% of ACC patients. Nevertheless, the aldosterone-producing ACC are even rarer. There is a bimodal occurrence by age, with a peak incidence at <5 years, and a second peak between 40 and 50 years [3]. The differentiation between benign and malignant neoplasms is often difficult by preoperative image. However, a tumour size of >4 cm should raise clinical suspicion of adrenocortical malignancy, even at a young age.