What is Cardiac Chromaffin Cell Pheochromocytoma?
Cardiac pheochromocytomas (CPs) are extremely rare tumors that originate inside the heart. These tumors typically develop from certain cells called sympathetic paraganglia, which are part of the body’s neuroendocrine system. This system produces hormones in response to signals from the nervous system. Paraganglia, in particular, are cells that are not part of the nervous system but come from the neural crest, an area in the developing embryo that contributes to many different parts of the body.
According to autopsies, primary cardiac tumors – where the tumor first forms in the heart – occur very rarely, ranging from 0.01 to 0.3% of the time. Of these, CPs are the rarest. Almost all (98%) pheochromocytomas, a type of tumor that releases a hormone called catecholamine, are found in the abdomen, and are most commonly located in the adrenal gland. Only less than 2% of these tumors are found in the chest, and the heart is the least common site of all.
Most reported cases of CPs have been benign, meaning they are not cancerous. However, if these tumors become malignant or cancerous, those which start from the heart tend to be more aggressive and harder to remove through surgery.
According to a clinical study which involved 158 patients, 85% of the 137 patients who underwent detailed imaging were found to have a tumor inside the pericardium, which is the sac that surrounds the heart. These tumors originated either from paraganglia located at the roots of the major blood vessels, or from paraganglia tucked in the folds between the chambers of the heart.
A significant detail to note about CPs is that they are highly vascular, meaning they have a lot of blood vessels. They get most of their blood supply from the coronary arteries, which are the blood vessels that supply the heart muscle itself.
What Causes Cardiac Chromaffin Cell Pheochromocytoma?
Even though we don’t have a lot of clear information, recent studies have shown that genetic mutations and family history can be the root cause for about 25% to 50% of cases of pheochromocytomas, which are rare tumors that develop in the adrenal glands. In a review of past medical literature, there was a report of one person who had a pheochromocytoma of the heart and also had multiple endocrine neoplasia (MEN), which is a condition that leads to the growth of tumors in the endocrine organs.
There are several genetic syndromes that are often associated with pheochromocytomas. These include Multiple Endocrine Neoplasia type 2 (caused by the RET gene), neurofibromatosis 1 (caused by the NF1 gene), Von Hippel-Lindau disease (caused by the VHL gene), and adrenocortical adenoma and/or endocrine tumors as seen in Carney’s triad and paraganglioma syndromes type 1, 3, and 4 (caused by the SDH gene).
Additionally, about 30% of patients with malignant adrenal pheochromocytomas, which are deadly tumors in the adrenal glands, and 48% of patients with malignant paragangliomas, which are deadly tumours found near the adrenal glands, are found to have mutations in the succinate dehydrogenase subunit B (SDH) gene. It’s also important to note that these heart pheochromocytomas can be associated with the mentioned syndromes.
Risk Factors and Frequency for Cardiac Chromaffin Cell Pheochromocytoma
Cardiac pheochromocytomas, or CPs, are the least common type of heart tumors. These growths are very rare, with primary heart tumors occurring in roughly 0.01 to 0.3% of people, as shown in autopsy studies. Even rarer, less than 2% of pheochromocytomas, a kind of tumor, are found in the chest, making CPs the rarest of them all. According to medical literature, fewer than 300 people have been diagnosed with CPs. Most people with CPs are around 40 years old at diagnosis, but ages can range from 12 to 85 years. Both men and women are equally prone to get these tumors. However, this data is limited and it should be noted that just under 0.2% of people with high blood pressure have these types of tumors which produce adrenaline-like hormones.
Signs and Symptoms of Cardiac Chromaffin Cell Pheochromocytoma
Cardiac pheochromocytomas are a type of heart tumor. The symptoms often relate to an overproduction of certain hormones and can range from noticeable physical manifestations to more general conditions. It’s interesting that unlike with other heart tumors, shortness of breath is not commonly seen with pheochromocytomas. Here are the symptoms you might experience:
- Palpitations (feeling your heart beat rapidly or irregularly)
- Sweating excessively
- High blood pressure
- Rapid heart rate (tachycardia)
- Dizziness or lightheadedness
- Headache
- Fainting spells (syncope)
- Unusual perspiration
- Flushing (redness of the skin)
- Chest pain (although this is less common)
- Fever, fatigue, and weight loss (these are nonspecific signs)
It’s important to note that while some people might not have any symptoms at all, this is quite rare.
Testing for Cardiac Chromaffin Cell Pheochromocytoma
A pheochromocytoma is a rare type of tumor that mainly develops in your abdomen, particularly in the adrenal parts of your abdomen, and it’s very rare to find them in your chest. To confirm or dismiss the suspicion of this type of tumor, doctors carry out laboratory tests using specific substances in your blood and urine. These substances are called metanephrines.
Doing these tests, they can determine with a high degree of certainty whether you have a pheochromocytoma or not. Plasma metanephrines tests have a 99% chance of accurately identifying the disease, and urine metanephrines tests have a 97% chance.
If these tests confirm the presence of a pheochromocytoma, doctors then have to figure out where exactly in your body the tumor is located using various imaging techniques. Since most of these tumors occur in the abdomen, this is the first area they’ll check using medical imaging.
Locating the tumor can sometimes be more challenging than diagnosing it. Various techniques can be used, such as CT or enhanced CT scans, PET scans, MRIs, echocardiograms, labeled metaiodobenzylguanidine (MIBG), or Tc labeled octreotide.
Among these imaging techniques, an MIBG scan is the most effective for finding not only the location of the tumor but also spread to other parts of your body, if any.
If the tumor is suspected to be situated closely to your heart, a type of echocardiogram can be used. Two types exist – a transthoracic echocardiogram (TTE) and a transesophageal echocardiogram (TEE). However, if the tumor has grown and attached itself extensively to the outer layer of the heart (the pericardium), both types of echocardiogram might fail to show it.
In such cases, doctors might prefer to use magnetic resonance imaging (MRI), which is more sensitive than both CT scans and echocardiograms in showing the tumor’s exact location and its relationship to surrounding structures.
Lastly, a procedure called cardiac catheterization or cardiac angiogram is used prior to surgery. This procedure helps to pinpoint not only the exact location of the tumor but also the blood vessels supplying them.
So in a nutshell, if pheochromocytoma is suspected, doctors first confirm it using laboratory tests and then use different imaging techniques such as MIBG scans, MRI, and cardiac angiogram to locate the tumor before planning for surgical intervention.
Treatment Options for Cardiac Chromaffin Cell Pheochromocytoma
The most effective way to treat heart tumors known as cardiac pheochromocytomas is through surgery to remove them. However, before surgery, it’s important to control and stabilize the patient’s blood pressure. This can be done by providing certain medications known as alpha-blockers (like doxazosin, urapidil, phenoxybenzamine) a few weeks before the operation.
Blood pressure can also be managed using other types of medicines, including calcium channel blockers (such as amlodipine, nifedipine) and angiotensin-converting enzyme inhibitors, which help relax and widen blood vessels.
One significant thing to know is that beta-blockers, another type of blood pressure medication, should not be used until the patient’s blood pressure is well-controlled with the help of alpha-blockers. If beta-blockers are used without first controlling blood pressure with alpha-blockers, it can lead to a condition called a catecholamine storm, which can result in a severe high blood pressure crisis.
Beta-blockers can be started only a few days before surgery to help control heart rate. It’s important to note that there’s currently no identified role for treatments like chemotherapy or radiation therapy in addressing this type of heart tumor.
What else can Cardiac Chromaffin Cell Pheochromocytoma be?
When doctors try to diagnose pheochromocytomas, a type of tumor, they must rule out many other conditions that can cause similar symptoms. The possibilities include:
- Adrenal pheochromocytomas (pheochromocytomas located on the adrenal glands)
- Hyperthyroidism (overactive thyroid)
- Thyroid storm (a severe, life-threatening form of hyperthyroidism)
- Cardiac arrhythmias (irregular heart rhythms)
- Carcinoid tumor (a type of slow-growing cancer that can arise in several places throughout the body)
- Migraine
- Stroke
- Medullary thyroid carcinoma (a type of thyroid cancer)
- Mastocytosis (a condition caused by an excessive number of mast cells)
Furthermore, if a patient has a confirmed heart mass, it could be several things, such as:
- Pericardial mass (a mass located in the pericardium, the sack that surrounds the heart)
- Abscess (a collection of pus)
- Metastasis (spread of cancer from the primary site to other parts of the body)
To make an accurate diagnosis, doctors have to consider all these potential conditions and may need to perform various tests.
Surgical Treatment of Cardiac Chromaffin Cell Pheochromocytoma
The best way to treat heart pheochromocytomas, which are rare, non-cancerous tumors that develop in the heart, is through a surgical procedure called resection. In this procedure, the tumor is carefully removed, or “resected,” from the heart.
What to expect with Cardiac Chromaffin Cell Pheochromocytoma
In a study involving 91 patients with a benign form of a condition known as CP, the survival rates were found to be quite high. Specifically, the one-year survival rate was 98.2% and the five-year survival rate was 78.8%. Though information is limited, it appears that most people recover well after the entire affected area has been removed surgically.
However, for those with a malignant, or cancerous form of CP, the outlook is less clear as there isn’t enough information available yet.
Possible Complications When Diagnosed with Cardiac Chromaffin Cell Pheochromocytoma
Complications from this health condition or the treatment procedure can occur. If the disease, a tumor that secretes stress hormones, isn’t treated, it can lead to several serious heart and blood vessel issues. These could include heart disease caused by blocked blood vessels, heart attack, irregular heartbeat, heart muscle disease, fluid in the lungs, stroke, and dangerously high blood pressure. The treatment procedure itself is also quite risky, mainly because the tumor has a high blood supply. In one study of 100 patients undergoing treatment, five people sadly passed away due to severe bleeding during the operation.
Possible Complications:
- Heart disease caused by blocked blood vessels
- Heart attack
- Irregular heartbeat
- Heart muscle disease
- Fluid in the lungs
- Stroke
- Dangerously high blood pressure
- Severe bleeding during operation
