No one seemed particularly concerned about my hip pain until I mentioned it was always worse at night. Then all of a sudden, I had a ticket to the MRI machine. They found a benign tumor (osteoid osteoma) in the upper portion of the femur. Why was this night pain the "hop to it" symptom?
Bone pain from osteoid osteomas usually occurs in young men between the ages of five and 24 (though it has been reported in older adults). Without knowing there's a tumor present (and without a more dramatic presentation), it's easy to think that the fellow is having growing pains. But pain at night that wakes the person up from a sound sleep is a red flag for cancer. Then the picture of a young person with bone pain at night suddenly becomes more compelling. Why does this type of pain develop? It turns out that cancer cells can signal the normal healthy tissue to form tiny blood vessels between the healthy tissue and the cancer. The process is called angiogenesis. The net effect is to siphon off blood to the tumor. This creates a loss of blood supply to the surrounding healthy tissue, a condition called ischemia. Without oxygen, the body sets up a pain response. Since most of this happens at night when the body is in a semi-state of hybernation, the symptoms don't occur during the day.