Utility of bone densitometry in diagnostic evaluation and monitoring in regional migratory osteoporosis.

Regional migratory osteoporosis (RMO) is a rare, self-limited disease of unknown etiology, characterized by migratory arthralgia of the weight-bearing joints of the lower extremities. RMO is most commonly seen in middle-aged adults, particularly men. Several case reports suggest that bone changes seen in RMO may be detected as focal decreases in bone mineralization, but the utility of serial bone density studies has yet to be formally evaluated in this syndrome. We describe a case of RMO with dramatic focal changes in bone mineral density that corresponded to the underlying clinical course. Serial bone density testing clearly documented significant bone loss and subsequent recovery of bone density in areas affected by RMO. Our data suggest that sequential densitometric examination of affected areas may be useful to confirm the diagnosis of RMO, and for subsequent monitoring of bone loss and therapeutic response.