Management of Hypermetabolic Focus in Left Adrenal Gland

Diagnostic Evaluation

A hypermetabolic focus in the left adrenal gland requires immediate comprehensive hormonal evaluation followed by characterization imaging to determine if this represents a functional tumor or other pathology, with surgical resection indicated for functional lesions 1, 2
Measure plasma free metanephrines or 24-hour urinary metanephrines immediately before any further intervention, as hypermetabolic activity on imaging strongly suggests catecholamine-secreting tumor 3, 4
Levels >2X upper limit of normal confirm pheochromocytoma 3

1 mg overnight dexamethasone suppression test to screen for autonomous cortisol secretion (cortisol >138 nmol/L indicates hypersecretion) 3, 4
Aldosterone-to-renin ratio if patient has hypertension or hypokalemia (ratio >20 ng/dL per ng/mL/hr indicates primary aldosteronism) 3, 4
Serum androgens (DHEA-S, testosterone, 17-OH progesterone) if adrenocortical carcinoma suspected or virilization signs present 3, 4

Non-contrast CT scan to measure Hounsfield Units (HU) and assess lesion characteristics 1, 2
Lesions with HU ≤10 are definitively benign (0% risk of adrenocortical carcinoma) 1
Lesions with HU >10 require second-line imaging with washout CT or chemical-shift MRI 4

Surgical resection is mandatory via minimally-invasive adrenalectomy when feasible for confirmed pheochromocytoma 3, 4
Unilateral adrenalectomy of affected gland via minimally-invasive surgery for cortisol-secreting lesion with clinical Cushing's 3, 5
Consider adrenalectomy for younger patients with progressive metabolic comorbidities attributable to cortisol excess after shared decision-making for mild autonomous cortisol secretion (MACS) 3, 5, 6
Adrenal vein sampling required for lateralization before surgery for aldosterone-secreting adenoma 3, 4
Unilateral adrenalectomy via minimally-invasive approach for confirmed unilateral aldosterone-secreting adenoma 3, 4

Obtain multidisciplinary review by endocrinologists, surgeons, and radiologists when imaging not consistent with benign lesion, evidence of hormone hypersecretion confirmed, tumor growth documented on follow-up, or adrenal surgery being considered 1, 2, 3, 5, 6

Never skip hormonal evaluation even if lesion appears benign radiologically, as 5% harbor subclinical hormone production 4
Never biopsy before excluding pheochromocytoma to avoid hypertensive crisis 4
Never delay surgery for functional tumors while pursuing additional imaging, as hormonal excess drives morbidity and mortality 4