Adrenocortical carcinoma is a rare cancer affecting the outside of the adrenal glands (adrenal cortex). These glands are on top of each kidney and are responsible for producing certain hormones and keeping blood pressure at normal levels. Adrenocortical carcinoma is relatively frequent in children compared to many other cancers, although the cancer may also affect adults. Girls are more often affected than boys. Symptoms of adrenocortical carcinoma may include pain in the abdomen, hypertension, weight gain, frequent urination and possibly deepening of the voice. These symptoms are due to the tumors causing excess secretion of hormones from the adrenal glands.
Adrenocortical carcinoma may develop by chance alone, but at least 50% of the cancers are thought to be hereditary. There are a number of genes that have changes (mutations) that can cause an adrenocortical carcinoma, including TP53 and IGF2. There have been reports of both autosomal dominant inheritance and autosomal recessive inheritance.
An adrenocortical carcinoma is diagnosed based on urine tests for abnormal levels of cortisol, the hormone released by the adrenal glands. Blood tests can also be conducted to measure levels of potassium and sodium in the blood. A CT scan or MRI may be used to search for a visible tumor in the adrenal cortex. Treatment options include surgical removal of the tumor, which is important to achieve a good long-term outlook. Chemotherapy, specifically a drug called mitotane, can be used to try to remove any remaining cancer after surgery.
- Fatty, rounded hump high on the back just below the neck (buffalo hump)
- Flushed rounded face with pudgy cheeks (moon face )
- Stunted growth in height (short stature)
- Virilization - the appearance of male characteristics, including increased body hair especially on face, pubic hair, acne, deepening of voice, and enlarged clitoris (girls) Symptoms that suggest increased aldosterone production are the same as symptoms of low potassium and include weakness, muscle cramps, increased thirst, and urination.
Adrenocortical carcinoma is most common in children younger than 5 and adults in their 30s and 40s. Adrenocortical carcinoma may be linked to a cancer syndrome that is passed down through families (inherited). Both men and women can develop this tumor. Adrenocortical carcinoma can produce the hormones cortisol, estrogen, or aldosterone. In women the tumor often releases the hormones, which can lead to male characteristics. The cause is unknown. About 2 people per million develop this type of tumor.
Hormonal syndromes should be confirmed with laboratory testing. Laboratory findings in Cushing syndrome include increased serum glucose (blood sugar) and increased urine cortisol. Adrenal virilism is confirmed by the finding of an excess of serum androstenedione and dehydroepiandrosterone. Findings in Conn syndrome include low serum potassium, low plasma renin activity, and high serum aldosterone. Feminization is confirmed with the finding of excess serum estrogen.
Radiological studies of the abdomen, such as CT scans and magnetic resonance imaging are useful for identifying the site of the tumor, differentiating it from other diseases, such as adrenocortical adenoma, and determining the extent of invasion of the tumor into surrounding organs and tissues. CT scans of the chest and bone scans are routinely performed to look for metastases to the lungs and bones respectively. These studies are critical in determining whether or not the tumor can be surgically removed, the only potential cure at this time.
Adrenal tumors are often not biopsied prior to surgery, so diagnosis is confirmed on examination of the surgical specimen by a pathologist. Grossly, adrenocortical carcinomas are often large, with a tan-yellow cut surface, and areas of hemorrhage and necrosis. On microscopic examination, the tumor usually displays sheets of atypical cells with some resemblance to the cells of the normal adrenal cortex. The presence of invasion and mitotic activity help differentiate small cancers from adrenocortical adenomas. There are several relatively rare variants of adrenal cortical carcinoma:
- Oncocytic adrenal cortical carcinoma
- Myxoid adrenal cortical carcinoma
- Adenosquamous adrenocortical carcinoma
- Clear cell adrenal cortical carcinoma
Differential diagnosis includes:
- Adrenocortical adenoma
- Renal cell carcinoma
- Adrenal medullary tumors
- Hepatocellular carcinoma
ACC, generally, carries a poor prognosis and is unlike most tumours of the adrenal cortex, which are benign (adenomas) and only occasionally cause Cushing's syndrome. Five-year disease-free survival for a complete resection of a stage I–III ACC is approximately 30%.
The outcome depends on how early the diagnosis is made and whether the tumor has spread (metastasized). Tumors that have spread often lead to death within 1 to 3 years.
The only curative treatment is complete surgical excision of the tumor, which can be performed even in the case of invasion into large blood vessels, such as the renal vein or inferior vena cava. The 5-year survival rate after successful surgery is 50–60%, but unfortunately, a large percentage of patients are not surgical candidates. Radiation therapy and radiofrequency ablation may be used for palliation in patients who are not surgical candidates.
Chemotherapy regimens typically include the drug mitotane, an inhibitor of steroid synthesis which is toxic to cells of the adrenal cortex, as well as standard cytotoxic drugs. A retrospective analysis showed a survival benefit for mitotane in addition to surgery when compared to surgery alone.
The two most common regimens are cisplatin, doxorubicin, etoposide + mitotane and streptozotocin + mitotane. It is unknown which regimen is better. Researchers at Uppsala University Hospital initiated a collaboration between adrenocortical cancer specialists in Europe, USA and Australia, to conduct the first ever randomized controlled trial in adrenocortical cancer (FIRM-ACT study, comparing these two regimens.