99mTc-MDP Bone Scan Findings of Recurrent Langerhans Cell Histiocytosis in an Adult Involving Femur After Joint Replacement.

Langerhans cell histiocytosis (LCH) is a rare proliferative histiocytic disorder. It mainly occurs in children and is rare in adults. We reported 99mTc-MDP bone scan findings of recurrent LCH in an adult, which involved the right femur after right-side total hip arthroplasty. This case emphasizes that the possibility of LCH should be considered in osteolytic lesions in adults, especially after joint replacement. In addition, LCH should be included in the differential diagnosis of prosthetic joint pain and abnormal 3-phase bone scan after prosthesis arthroplasty.