Spontaneous Resolution of an Osteochondroma.

A 13-year-old girl presented with an apparent classic osteochondroma. Because she was skeletally immature, the decision was made to observe the lesion. She returned to the clinic at age 17 for unrelated reasons and was noted to no longer have the palpable mass. Magnetic resonance imaging confirmed resolution of the osteochondroma. The age range of this case fits with reported cases of childhood osteochondromas. The mechanism of resolution has been theorized to be incorporation of the lesion back into the bone during remodeling, fractures, or pseudoaneurysms. An initial period of observation is thus recommended with new patients.