Malignant pericardial effusion often remains a hidden manifestation of advanced lung cancer. In many clinical settings, doctors may misdiagnose the condition as a common respiratory or cardiac ailment. Therefore, maintaining a high index of suspicion is vital for timely management. This is especially true when patients exhibit persistent cardiorespiratory symptoms despite receiving standard therapy. However, the subacute nature of some effusions can mask traditional signs of hemodynamic distress, such as hypotension.

A recent case report describes a 54-year-old Malaysian woman who presented with a three-week history of productive cough, fever, and dyspnea. Clinicians initially treated her for community-acquired pneumonia. Despite receiving intravenous antibiotics and drainage for a pleural effusion, her condition did not improve. Consequently, the medical team performed computed tomography pulmonary angiography (CTPA) to rule out other complications. The imaging unexpectedly revealed a circumferential effusion and subsegmental emboli.

Diagnosing Malignant Pericardial Effusion

Early diagnosis of malignant pericardial effusion requires a multi-modal approach. Although the patient in this case was normotensive, echocardiography confirmed tamponade physiology. This finding demonstrates that subacute fluid accumulation allows the pericardial sac to stretch, thereby maintaining blood pressure initially. Therefore, physicians should not rely solely on blood pressure to rule out cardiac tamponade. Urgent pericardiocentesis subsequently drained 600 mL of hemorrhagic fluid from the patient.

Furthermore, pericardial fluid cytology proved essential in this diagnostic journey. The analysis revealed malignant adenocarcinoma cells, pointing toward an occult primary tumor. PET-CT later identified a hypermetabolic right upper lobe mass with widespread metastases to the pleura, bones, and adrenal glands. This case highlights how lung cancer can present atypically in women, where breast cancer more frequently causes such effusions. Ultimately, multidisciplinary collaboration between cardiology, oncology, and pulmonology ensured a comprehensive management plan.

Frequently Asked Questions

Can cardiac tamponade occur with normal blood pressure?

Yes. In subacute cardiac tamponade, the pericardial sac stretches gradually over days or weeks. This allows compensatory mechanisms to maintain systemic blood pressure, resulting in a normotensive presentation despite significant hemodynamic impact on the heart.

Why is pericardial fluid cytology important in occult cancer?

Pericardial fluid cytology can directly identify malignant cells when initial imaging of the primary tumor remains inconclusive. In many lung cancer cases, analyzing hemorrhagic fluid provides the first definitive evidence of metastatic adenocarcinoma.

Disclaimer: This content is for informational and educational purposes only and does not constitute medical advice. It is not a substitute for professional medical judgment, diagnosis, or treatment. Always seek the advice of a qualified healthcare provider with any questions regarding a medical condition. Refer to the latest local and national guidelines for clinical practice.

References

Mohd Zulastri MA et al. Subacute normotensive cardiac tamponade as the initial presentation of metastatic lung adenocarcinoma: a case report. J Med Case Rep. 2026 Jun 06. doi: 10.1186/s13256-026-06173-x. PMID: 42251461.

Adler Y, et al. 2015 ESC Guidelines for the diagnosis and management of pericardial diseases. European Heart Journal. 2015;36(42):2921-2964.

Gornik HL, et al. Evaluation of Patients with Pericardial Effusion. Circulation. 2005;111(13):e180-e185.