Occult infection as a cause of hip pain in a patient with metastatic breast cancer.

A 39-year-old woman with breast cancer metastatic to bone presented with acute hip pain marginally responsive to escalating doses of opioid analgesics. Pathologic pelvic fractures were present and there were minimal clinical indicators of infection, but the severity and intractable nature of the pain prompted further investigation. Computed tomography revealed a pelvic abscess. Antibiotic therapy and drainage of the abscess resulted in markedly improved pain control, decreased analgesic requirements, and improved quality of life. We suggest that, in patients with malignancy, the diagnosis of occult infection should be aggressively pursued as a potentially reversible cause of intractable pain.