Evaluating the functional status of adrenal tumors suspicious for ACC is essential, not only for making the diagnosis of ACC but also for consideration of postoperative cortisol replacement and the potential use of tumor-secreted hormones as markers during postoperative surveillance.
When considering the functional status of a tumor that raises suspicion for ACC, glucocorticoid, mineralocorticoid, catecholamine, sexual steroid, and steroid precursor excesses should be evaluated
In incidentally detected adrenal tumors, size is a relative indicator of malignancy
Risk of malignancy based on tumour size:
< 4 cm: 5%
> 4 cm: 10%
> 6 cm: 25%
Given the relationship between size and malignancy, it is currently recommended that adrenal tumors > 4-6 cm be surgically excised
ACCs tend to be larger than benign adrenal tumors, with an average size of 10-12 cm on presentation
Radiographic characteristics of ACCs on CT imaging (5):
Irregular borders
Heterogenous enhancement
Increased enhancement (mean 39 HU) compared to adenoma (8 HU)
Calcifications
Necrotic areas with cystic degeneration
MRI§
Normal adrenal gland
TI: uniform intermediate signal intensity that is slightly less intense than that of the liver and renal cortical tissue
T2: difficult to distinguish from retroperitoneal adipose tissue because of the presence of intracellular lipid with the gland
Myelolipoma
T1: bright
T2: intermediate
ACCs
T1: isointense relative to the liver or spleen
T2: intermediate to increased intensity
Marked contrast uptake on gadolinium-enhanced images
Pheochromocytoma
Classically, bright signal intensity on T2-weighted imaging (best seen on fat suppression sequences)—termed the “light bulb” sign—was believed to be diagnostic. It is now clear that this imaging characteristic is neither specific nor sensitive enough to secure a diagnosis and must be interpreted with caution
Percutaneous needle biopsy is usually not performed before surgical excision owing to a clinically unacceptable risk of needle-tract seeding.
In cases of surgically resectable disease, the information obtained from biochemical and radiographic evaluation should be enough to justify extirpation.
Multimodal treatment, surgical resection, radiation therapy, and systemic chemotherapy are often necessary
Systemic chemotherapy
Mitotane
Oral synthetic derivative of the insecticide dichlorodiphenyltrichloroethane (DDT)
Mechanism of action: inhibits several enzymes of the adrenal cortex including the cholesterol side-chain cleavage enzyme (P450scc, CYP11A1), 11β-hydroxylase (CYP11B1), 18-hydroxylase (aldosterone synthase, CYP11B2), and 3β-hydroxysteroid dehydrogenase (3β-HSD) to a lesser extent
Most commonly used chemotherapeutic agent in the treatment of adrenal cortical carcinoma
In patients with a history of a previous malignancy, >50% of newly discovered adrenal lesions are metastatic; nevertheless, metabolic workup in these patients is recommended.
Bilateral and bulky disease (>4 cm) is necessary to produce biochemical evidence of adrenal insufficiency
Current imaging modalities supplemented by adrenal biopsy, when necessary, can frequently differentiate metastases from a primary adrenal tumor.