Familial expansile osteolysis—not exclusively an adult disorder

Familial expansile osteolysis (FEO, MIM174810) is a rare syndrome which was observed world-wide in only three kinships and in two unrelated American individuals. We report a patient with familial expansile osteolysis from the Czech Republic, not related to the previously reported cases. This patient’s extraordinary clinical course does not conform to the ordinary. Her radiographic bone involvement was unusually extensive, involving most of the peripheral skeleton and the skull. This case documents that familial expansile osteolysis is not only a disease of adults but does occur in childhood.