Stress reaction of the humerus in a high school baseball player.

The patient was an 18-year-old high school baseball pitcher with a chief complaint of right (dominant) arm pain in the region of his right distal humerus that began 8 weeks earlier. Conventional radiographs were obtained, which were interpreted as normal. As a result, magnetic resonance imaging was obtained, which showed a hyperintense bone marrow signal in the distal humerus on fluid-sensitive sequences, which was consistent with a stress reaction of the distal humerus.