Importance of imaging in knee pain.

A 72-year-old woman with a prior history of stage IIIa lung adenocarcinoma was seen with complaints of knee pain, swelling, and difficulty sleeping at night for 1 month. Although mimicking osteoarthritis, patellofemoral syndrome, and iliotibial band syndrome, radiographs showed a lytic lesion suspicious for metastatic disease. The right tibial lesion was excised, saphenous neurolysis was performed, and radiation treatment and four cycles of chemotherapy were administered. This case shows the importance of early imaging in patients with knee pain of prolonged duration seen in the primary care setting.