Septic Iliac vein thrombophlebitis with associated psoas abscess is a rare and severe entity, which diagnosis is challenging when no risk factor is clearly present. We are presenting a case of severe septic cavitary pulmonary emboli complicated with Acute Respiratory Distress Syndrome (ARDS) that evolved rapidly to respiratory distress and multi organ failure. A 61-year-old Hispanic male, had multiple emergency department visits due to back pain, being most of them intramuscular pain medications and steroids. In the history, he had back pain that worsened accompanied by poor mobility, generalized malaise, fever and chills. Computed tomography (CT) scan showed a paravertebral psoas abscess with L5-S1 diskitis/spondylitis infl ammatory changes, which was then later evidenced by a gallium study. Further imaging studies were done, showed bilateral cavitary lung lesions, consistent with septic emboli. Subsequent blood cultures were positive for Methicillin Resistant Staphylococcus Aureus (MRSA), for which a successful combined therapeutic regimen was used. Transthoracic and transesophageal echocardiogram were not suggestive of endocarditis. Staphylococcus aureus (SA) bacteremia is one of the most common serious bacterial infections with a high risk of metastatic complications, which makes this pathogen a unique one. The combination of factors iliac vein thrombophlebitis, psoas muscle abscess, diskitis/spondylitis with ARDS makes cavitary pulmonary disease a challenging perspective. After a 6-week antimicrobial treatment, full anticoagulation, his clinical condition and image fi ndings improved, and he was recently admitted for physical rehabilitation. Major vessels thrombophlebitis should always be considered, when primary source of septic pulmonary emboli is not clear. This case illustrates the complexity of illness and complications that may arise from a source of infection as the one in this patient. Further therapeutic strategies were tailored accordingly.