Giant Pericardial Cyst in the Right Cardiophrenic Angle Mimicking a Hydatid Cyst: A Case Report of a Diagnostic Challenge in an Endemic Region
This case report describes a 57-year-old Syrian male with a giant pericardial cyst mimicking a hydatid cyst due to positive serology in an endemic region, which was successfully treated via open thoracotomy after surgical excision confirmed the benign diagnosis.
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Inside the chest, nestled between the heart and the lungs, lies a space that usually remains quiet and empty. Occasionally, however, a fluid-filled sac forms in this area, a benign growth known as a pericardial cyst. These are rare, non-cancerous pouches that develop from the lining of the heart, most often appearing in the lower right corner where the heart meets the diaphragm. While many people carry these cysts without ever knowing it, they can grow large enough to press against the heart or lungs, causing shortness of breath or chest discomfort. The challenge for doctors arises when these sacs look exactly like something far more dangerous, such as a parasitic infection, leading to a difficult puzzle where the wrong diagnosis could lead to unnecessary or even harmful treatment.
In a recent report from Syria, a team of surgeons and researchers described a particularly striking example of this diagnostic puzzle. They treated a fifty-seven-year-old man who had begun to feel slightly out of breath when he exerted himself. A routine X-ray of his chest revealed a large, uniform shadow in the lower right side of his lung field. To understand what this shadow was, the medical team turned to a detailed scan of the chest, which showed a massive, fluid-filled sac measuring nearly fifteen centimeters in its longest dimension. This size was extraordinary; while most of these cysts are small enough to go unnoticed, this one was a giant, occupying a significant portion of the chest cavity.
The situation became complicated because the region where the patient lived is known for a specific parasitic disease called echinococcosis, which causes cysts to form in the liver and lungs. When the doctors tested the patient's blood, they found antibodies that typically signal the presence of this parasite. This result was a red herring, a misleading clue that pointed the investigation toward a parasitic infection rather than a simple cyst. In a region where this parasite is common, a positive blood test usually demands extreme caution, because puncturing a parasitic cyst can release toxic contents into the body and cause a severe allergic reaction. Consequently, the medical team could not simply drain the fluid with a needle, a procedure that is sometimes used for less dangerous cysts. They had to assume the worst and prepare for a major surgery that would allow them to remove the entire sac without breaking it.
The patient underwent a surgical procedure where the surgeons opened the chest wall to reach the mass directly. Inside, they found a large, thin-walled sac attached to the lining of the heart, but it did not connect to the heart's own fluid chamber. The surgeons carefully separated the sac from the surrounding lung tissue and heart, then drained the clear fluid inside to make the mass smaller and easier to remove. Once the fluid was gone, they peeled the entire wall of the cyst away from the body. Crucially, when they examined the inside of the removed sac, they found no evidence of the parasitic membranes that would have confirmed a hydatid cyst. Instead, the tissue was smooth and clean, confirming that the mass was indeed a benign pericardial cyst, despite the confusing blood test results.
Following the operation, the patient recovered quickly. The fluid that drained from his chest after surgery decreased rapidly over two days, and his lungs expanded fully. He was able to walk and eat normally within a few days and was sent home just three days after the surgery, with his breathing problems completely resolved. The final diagnosis, confirmed by examining the removed tissue under a microscope, was a simple, harmless cyst. This case serves as a reminder that even when blood tests suggest a dangerous infection, the physical appearance of a mass and the results of a careful surgical removal can tell a different story. It highlights the importance of not relying on a single test, especially in areas where diseases overlap, and shows that even the largest of these cysts can be removed safely when the surgical team is prepared for the unexpected.
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