Imaging of oncologic emergencies: what every radiologist should know.

Acute life-threatening conditions in oncology patients may develop either because of underlying malignancy or as a complication from treatment. Oncologic emergencies can be categorized as metabolic, hematologic, and structural conditions. Metabolic and hematologic emergencies are mainly diagnosed on the basis of clinical and laboratory findings. Structural pathologic conditions that result in bleeding, mechanical compression, or obstruction to the hollow organs, such as the trachea and bowel loops, may first be suspected because of clinical findings, including decreasing hematocrit levels, difficulty in breathing, and abdominal pain; however, performance of imaging studies is critical for timely diagnosis and management. Life-threatening conditions of the central nervous system (such as cerebral herniation, carcinomatous meningitis, and spinal cord compression), thoracic emergent conditions (such as central airway obstruction, esophagorespiratory fistula, massive hemoptysis, pulmonary embolism, superior vena cava syndrome, and pericardial tamponade), and abdominopelvic emergencies (such as uncontrolled intraabdominal hemorrhage, bowel obstruction, intestinal perforation, bowel ischemia, intussusception, and urinary tract obstruction) can be definitively diagnosed on the basis of projectional or cross-sectional imaging findings in appropriate clinical scenarios. Select emergent conditions in cancer patients related to chemotherapy and radiation treatment, as well as iatrogenic emergencies secondary to either surgery or placement of central venous catheters, may also demonstrate characteristic findings at imaging studies. In addition, interventional procedures are of great help in the treatment of acute superior vena cava syndrome, massive hemoptysis, and uncontrolled intraabdominal hemorrhage. Radiologists should be aware of these select, "not to be missed" imaging findings of oncologic emergencies to make an accurate, timely diagnosis and provide appropriate patient care.