Incidentally Discovered Adrenal Masses: a Functional and Morphological Study

Summary

In the last two years we have examined 17 consecutive patients (11 females and 6 males, 20 — 66 years old) in whom an unsuspected adrenal mass was discovered by ultrasonography or computed tomography performed for unrelated reasons. Pathological diagnosis was available in 11 cases based on surgical excision in 9 (2 pheochromocytomas of 5 and 12 cm in diameter; 2 ganglioneuromas of 5 and 6 cm; and 5 benign cortical adenomas between 3 and 5 cm), autopsy in 1 (a disseminated malignant pheochromocytoma of 16 cm) and fine-needle biopsy in 1 (a pseudoadrenal mass of 6 cm, that was a regenerative hepatic nodule). The remaining 6 non histologically diagnosed masses were less than 3 cm in diameter. Endocrine studies showed elevated urinary excretion of catecholamines, vanillylmandelic acid and metanephrines in the pheochromocytomas and borderline high values in ganglioneuromas. A low plasma renin activity was encountered in 2 operated cortical adenomas and 3 non operated incidentalomas. In 2 of the latters aldosterone serum levels were elevated and the final diagnoses respectively were Conn's adenoma and dexamethasone-suppressible hyperaldosteronism with bilateral nodular hyperplasia. An inappropriate cortisol secretion was documented in a cortical adenoma removed. Radiocholesterol scintiscan showed unilateral or increased uptake on the side of adrenal mass (concordant uptake) in the 5 benign cortical adenomas removed and in 4 non operated incidentalomas. A decreased uptake on the side of the adrenal mass (discordant uptake) was found in the 2 ganglioneuromas while an undeterminate bilateral uptake was found in the 2 remaining non operated incidentalomas and in the pseudoadrenal mass. 131-I MIBG scintiscan showed an increased concordant uptake in the two benign pheochromocytomas and in one ganglioneuroma. No uptake was found in one removed cortical adenoma and in two non operated incidentalomas. These data emphasize that, although the majority of these masses are benign cortical adenomas, hyperfunctioning or malignant lesions should be carefully identified and removed.

Key words

Adrenals - Adrenal tumors - “Incident-alomas”