Pheochromocytomas are located in the adrenal glands and paragangliomas are located along the paraspinal sympathetic chain in the chest, abdomen, and pelvic cavity, both of which are jointly known as PPGL[1]. The annual incidence of PPGL is approximately 8 per million while cardiac paragangliomas account for less than 2% of all paragangliomas and less than 1% of all cardiac tumors[2-4]. PPGL is considered to occur in 0.05% to 0.1% of patients with persistent hypertension. However, this accounts for only 50% of patients with PPGL due to the rest only having paroxysmal hypertension or normal blood pressure[1]. The disease is usually diagnosed between the age of 30 and 50 and approximately 10% to 49% of patients are discovered incidentally during imaging studies for other reasons[5-7].
PPGL are classified by the presence or absence of distant metastases, rather than histological features of the tumor. In 2017, the World Health Organization (WHO) replaced the "malignant PPGL" defined in 2004 with "metastatic PPGL" in the classification of neuroendocrine tumors. Metastatic PPGL is considered if metastatic lesions occur in nonchromaffin cell tissues such as bone, liver, lung, lymph nodes, brain, or other soft tissues. Metastatic PPGL was not considered in this patient because PET-CT showed cardiac occupying and no tumor lesions were found in other parts of the body.
The main signs and symptoms of excess circulating catecholamines from PPGL are headache, palpitations, sweating, pallor, nausea, constipation, flushing, weight loss, fatigue, anxiety, sustained or paroxysmal hypertension, orthostatic hypotension, fever, and hyperglycemia[1, 8]. These episodes are related to catecholamine excess produced by the tumor. Unexplained orthostatic hypotension on a background of paroxysmal or refractory hypertension may be an important diagnostic clue that may help clinicians to suspect this tumor [9]. In this article, we describe a rare case of intracardiac paraganglioma. The patient was hospitalized with cough, a rare symptom of catecholamine-associated tumor that may have been caused by irritation of the trachea by pericardial effusion resulting from the tumor. The occasional transient rise of blood pressure during diagnosis and treatment suggests the possibility of catecholamine-related tumors, which is further confirmed by PET-CT. In addition, to our knowledge, the brown adipose intake is diverse, mostly in cold seasons and young, female subjects with low BMI. When there is abnormal catecholamine-related secretion, brown adipose intake can also occur, often symmetrically involving the neck and shoulder, supraclavicular area, both sides of the spine, around mediastinal great vessels, adrenal area, and perirenal area[10]. Therefore, after excluding relevant factors such as gender and environment, we have more reason to believe that it is a catecholamine-related tumor. Regrettably, owing to the COVID-19, the patient was unable to carry out the preoperative catecholamine concentration test in other hospitals. This case provides valuable experience for us to treat similar patients in the future. After the diagnosis, the tumor should be removed in surgery as early as possible. Surgery can improve symptoms, reduce hormone secretion, prevent associated complications, and improve the outcome of subsequent treatment. However, crushing the tumor during surgery can lead to a massive release of catecholamines, which may cause a hypertensive crisis, arrhythmia, stroke, etc., and postoperatively, as a result of a dramatic reduction of catecholamines, may cause peripheral vasodilatation, resulting in persistent hypotension, and even death. Therefore, during the patient's hospitalization, multidisciplinary consultation should be strengthened, including the endocrine department, intensive medicine, anesthesiology department, and other disciplines, to ensure patient safety maximization. Postoperative follow-up should be lifelong.