A Rare Triad of Pulmonary Embolism, Inferior Vena Cava Thrombosis, and Hepatic Cyst Compression Revealing Occult Non-small Cell Lung Cancer.

We present the case of a 74-year-old woman who was admitted with acute shortness of breath and ultimately diagnosed with bilateral pulmonary emboli, inferior vena cava thrombosis, and a rapidly enlarging hepatic cyst. The cyst was compressing the inferior vena cava and contributing to thrombus formation. Her hospital course was further complicated by a diagnosis of metastatic non-small cell lung cancer harboring an epidermal growth factor receptor exon 19 deletion. This particular clinical scenario highlights the importance of maintaining a broad differential diagnosis when assessing pulmonary embolism, particularly in the absence of clear provoking factors. It illustrates how vascular obstruction, mass effect from benign lesions, and malignancy-associated hypercoagulability can converge to create a complex clinical picture.