Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy) is an unusual form of histiocytic disorder predominantly affecting children and young adults. Bone lesions are infrequent. We describe a 63-year-old woman with a solitary lesion of the talus which was misdiagnosed for 25 years. The patient never had adenopathy or other organ involvement. The radiographic findings were a mixture of sclerotic and lytic changes, an extremely rare and unusual presentation of the disease.