Pericardial cyst

Pericardial cysts most often are asymptomatic, with 50 to 75% of patients experiencing no symptoms.[1][2] The presentation of symptomatic cysts depends on the cyst location and effects on nearby structures, including the heart, lungs, and esophagus.[2][3] Symptoms can include chest pain, cough, shortness of breath, palpitations, syncope, recurrent pneumonia, congestive heart failure, difficulty swallowing, and weight loss.[1][2][3]

Pericardial cysts can be congenital or acquired, with the majority being congenital.[2][3] Congenital pericardial cysts happen due to an abnormality in the development of the pericardial sac that creates a bulge which is walled off to form a cyst.[1][3] Acquired pericardial cysts can be caused by inflammation from surgery, pericarditis, trauma, echinococcosis, tuberculosis, metastasis, or hemodialysis.[2][3] The inflammation can lead to a walled-off pocket of fluid that is a pericardial cyst.[3]

Since pericardial cysts are often asymptomatic, the most common diagnosis is through incidental finding on a chest x-ray.[1][2] When patients have symptoms, transthoracic echocardiogram is one of the first tests used to look for a pericardial cyst.[3] CT or MRI may also be used to diagnose pericardial cysts.[4][5][6] On CT and MRI a pericardial cyst will commonly appear as a round, fluid-filled structure surrounded by thin walls.[4][5][6] Diagnosis of a pericardial cyst can also be made before birth using ultrasound.[2]

The differential diagnosis for a suspected pericardial cyst includes a bronchial cyst, pericardial effusion, teratoma, lymphangioma, pericardial fat, congenital diaphragmatic hernia, neuroenteric cyst, and congenital cyst from the primitive foregut.[1][2][3] A pericardial cyst also may look similar on imaging to a pericardial diverticula, which is connected to the pericardium and not fully walled off like a pericardial cyst.[4]

Pericardial cysts that are small and cause no symptoms can be followed with repeat imaging through echocardiogram, CT, or MRI to assess for changes.[1][2] Pericardial cysts that are large or cause symptoms may be candidates for percutaneous aspiration, ethanol sclerosis, or surgery.[1][2][3] Percutaneous aspiration removes the fluid from inside the cyst, and ethanol sclerosis uses the injection of ethanol into the cyst after aspiration to decrease the likelihood of cyst recurrence.[2][3] Percutaneous aspiration with ethanol sclerosis is typically the first treatment for pericardial cyst that requires management.[2][3] Surgery can remove a pericardial cyst through a thoracotomy, sternotomy, mediastinoscopy, or video-assisted thoracic surgery.[1][2] The type of surgery is chosen based on the size and location of the pericardial cyst.[2]

With most pericardial cysts having no symptoms, the prognosis is very good.[1] The cysts can resolve without intervention.[1][3] If percutaneous aspiration is performed, the recurrence rate of pericardial cysts is about 30-33%.[1][3] Although pericardial cysts are benign, the location of cysts can rarely cause life-threatening emergencies by compressing the heart or lungs.[1][2]

Pericardial cysts have an incidence of 1 in 100,000.[2][6] Pericardial cysts make up 6-7% of all mediastinal masses.[2][3] They can present at any age, but are most commonly diagnosed between the third and fifth decade of life.[2][3] Females and males have approximately equal incidences of pericardial cysts.[2]

Pericardial cysts were first reported on during autopsies in the 19th century by pathologists.[2][7] As the field of radiology progressed, pericardial cysts could be identified in living patients.[2][7] In 1931, the first surgical resection of a pericardial cyst was performed by Otto Pickhardt at Lenox Hill Hospital in New York using a thoracoscopy.[2][7] In 1943, Greenfield and his colleagues coined the term "spring water cysts" for pericardial cysts since the cysts contain clear fluid.[2][7]