Fernanda E. Rivera-Sánchez, Department of Radiation Oncology, Hospital de Especialidades, Centro Médico Nacional de Occidente, IMSS, Guadalajara, Jal., Mexico
Rafael S. Cacelín-Miranda, Department of Internal Medicine, Hospital de Especialidades, Centro Médico Nacional de Occidente, IMSS, Guadalajara, Jal., México
Raúl A. Jiménez-García, Department of Internal Medicine, Hospital de Especialidades, Centro Médico Nacional de Occidente, IMSS, Guadalajara, Jal., México
Emanuel Montes-Verde, Department of Internal Medicine, Hospital de Especialidades, Centro Médico Nacional de Occidente, IMSS, Guadalajara, Jal., México
Lenyn D. Montes-Sevilla, Department of Surgery, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
Tania G. Rodríguez, Department of Internal Medicine, Hospital de Especialidades, Centro Médico Nacional de Occidente, IMSS, Guadalajara, Jal., México

Malignant pericardial effusion (MPE) is an uncommon but serious presentation of advanced lung adenocarcinoma. We report two cases where MPE was the initial manifestation, diagnosed through imaging, echocardiography, pericardiocentesis, and cytology. Both patients died before receiving oncologic treatment, underscoring the poor prognosis associated with MPE. Findings are contextualized with a literature review on diagnosis, prognosis, and management. This report highlights the need to consider malignancy in acute pericardial effusions and emphasizes the importance of a multidisciplinary approach to ensure early recognition and timely therapeutic interventions to improve outcomes.

Keywords: Pericardial effusion. Pulmonary adenocarcinoma. Neoplasms. Complications. Case reports.