Pheochromocytoma is a rare tumor that occurs in the adrenal gland called pheochromocytomas. These tumors can cause severe symptoms, including high blood pressure and heart problems. Pheochromocytoma has been known to occur in people of different races and ethnic backgrounds. In fact, they were first discovered in 1885 by a man named John Mackenzie who was later diagnosed with hypertension.
While not many cases of pheochromocytomatosis have been reported, those who do suffer from this rare condition often experience extreme episodes of high blood pressure leading to sudden death. Because pheochromocytomas are extremely rare, little research has been done into their causes and treatment. However, some treatments have proven effective in treating these types of conditions. Clinical manifestations of Pheochromocytoma depend on whether they are benign or malignant. Benign lesions produce no symptoms, whereas malignant lesions cause hypertension, headaches, palpitations, sweating, anxiety, diaphoresis, nausea, vomiting, abdominal pain, diarrhea, and weight loss. In addition, these tumors may lead to hypercalcemia, hypokalemia, and metabolic alkalosis.
One study showed that patients suffering from pheochromocytomas had significantly higher levels of cortisol than normal individuals. Cortisol is a hormone that helps regulate blood pressure and heart rate. Therefore, researchers theorized that high cortisol levels may play a role in causing pheo-chromoytoms. Another study showed that people who suffered from pheo-chrome-tomy had lower levels of dopamine and norepinephrine compared to normal individuals. Dopamine and norepinephrine are hormones responsible for regulating blood pressure and heart rate respectively. Researchers believed that low concentrations of these hormones could lead to pheo-chromotma.
Researchers are still unsure what causes Pheochromocytoma. One theory suggests that the disorder could arise from genetic mutations in the gene encoding the enzyme phenylethanolamine N-methyltransferase (PNMT). Enzymes are substances in the cells that help break down chemicals in the body. If the genes coding for PNMT is mutated, then the enzymes cannot properly metabolize adrenaline and epinephrine. Consequently, the amount of adrenaline and epinephrine in the bloodstream increases and may contribute to a rise in blood pressure. Other theories suggest that the disorder arises due to malfunctioning of receptors located inside the adrenal glands.
According to the Mayo Clinic, Pheochromocytoma are benign tumors that develop in the adrenal gland. While the exact cause of pheo-chromotomata is unknown, the incidence of the disease is relatively small. According to the National Institute of Health, approximately 8 out of 1 million adults between the ages of 20 and 60 years old are affected by the disease.
Because pheo-chromocytes are highly sensitive, it is difficult to determine whether the tumor is benign or malignant. Symptoms include headaches, nausea, vomiting, palpitations, shortness of breath, chest pain, sweating, diarrhea, weight loss, and fatigue. An individual’s age and gender may affect the severity of symptoms experienced by a patient.
The best way to diagnose the illness is with imaging tests. Blood tests check for elevated levels of catecholamines and other hormones, which may indicate the presence of the disease. A CT scan and MRI scans may be able to detect tumors in the adrenal gland, while ultrasound scans can reveal masses in the kidney. After the diagnosis, doctors can prescribe medications to control blood pressure and treat any complications arising from the disease.
In humans, PHEO is often associated with familial paraganglioma syndrome type 2, which is characterized by multifocal PHEO and extra-adrenal tumor localization. Familial forms occur in approximately 5–10% of patients with sporadic PHEO.
The diagnosis of PHEO requires histopathology and immunohistochemistry. Histologically, PHEO is have nests of uniform round to oval cells with abundant cytoplasm containing granular eosinophilic material. Immunohistochemical staining shows positive reactivity for chromogranin A, synaptophysin, and neuron-specific enolase.
Medical treatment consists of alpha receptor blockade using phenoxybenzamine hydrochloride (an alpha blocker). Alpha-blockers act by blocking the effects of catecholamines released by the tumor resulting in decreased blood pressure and heart rate. Phenoxybenzamine hydrochloride is not curative; however, it decreases the frequency of episodes and prevents complications associated with uncontrolled hypertension.
Surgery is for symptomatic animals or those with metastatic disease. Surgical removal of the tumor is performed via open laparotomy or thoracotomy. You should go for complete Removal of the adrenal gland if complete resection is possible. If the tumor is unresectable, go for debulking surgery. Postoperative medical management should begin immediately following surgical intervention.
Surgical excision alone is rarely successful due to rapid local recurrence. Metastases to regional lymph nodes and distant sites are common. Therefore, adjuvant therapy is effective in these cases. Radiation therapy is effective in decreasing the size of recurrent masses and preventing further metastasis. Chemotherapy has shown no benefit in the treatment of canine PHEO.
How Common Are Pheochromocytomas?
The incidence rate of pheochromocytomata is unknown. However, if left untreated, they can result in death. In fact, people who have had pheochromocytoma have died due to complications caused by their tumors.
Who Gets Pheochromocytoamas?
Anyone can get them at any age. Pheochromocytherocytomas occur in both men and women, although they appear more often in women than in men. There is no known risk factor for developing this condition.
What Causes Pheochromocythemias?
There are two types of pheochromocytoma; benign and malignant. Benign pheochromocytoma occurs when cells produce excess amounts of adrenaline and noradrenaline. Malignant pheochromocytoma occurs when these cells become cancerous and begin producing excessive amounts of epinephrine. Both conditions share similar symptoms.
What Is the Treatment for Pheochromocytomas?
Treatment options depend upon whether the person has benign or malignant pheochromocytoma. If the patient does not have severe symptoms, then surgery is the best option. Surgery will remove the tumor and prevent further production of adrenaline and noradrenaline. Chemotherapy and radiation therapy are also treatment methods for this. However, chemotherapy and radiation therapy do not always work well with pheochromocytoma.
How often do we encounter pheoectochromocytoma?
Most cases occur sporadically without any family history. Occasionally, it occurs in association with neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant genetic disorder that affects approximately 1 in 3000 individuals. In addition, it may rarely develop as a paraneoplastic syndrome associated with endocrine cancers including breast cancer, lung carcinoid tumor, prostate cancer, and gastrin-producing pancreatic neuroendocrine tumors.
Where does a pheochromocytoma tumor originate?
It originates from chromaffin cells located in the adrenal gland.
Which organs/systems pheochromocytoma attacks?
CNS – Central nervous system.
Cardiovascular – Heart, blood vessels, arteries, veins, valves, heart muscle, cardiac conduction system.
Endocrine – Adrenals, pituitary gland, pancreas, thyroid gland, gonads (ovaries, testes), accessory glands.
Digestive tract – Esophagus, stomach, intestines, liver, gallbladder, bile ducts, spleen, appendix, colon, rectum, anus.
Respiratory System – Lungs, trachea, bronchi, alveoli, bronchioles, pulmonary vasculature.