title: Disappearance of giant cells and presence of newly formed bone in the pulmonary metastasis of a sacral giant-cell tumor following denosumab treatment: A case report.
abstract: A giant-cell tumor of the bone (GCTB) is a benign but locally aggressive bone tumor. Recently, the receptor activator of nuclear factor κB (RANK) ligand inhibitor, denosumab, has demonstrated activity against giant-cell tumors. The current study reports a case of a sacral GCTB with lung metastasis. A 19-year-old male patient presented with right buttock pain and right lower leg pain, and a sacral GCTB was diagnosed based on the histological analysis of a biopsy specimen. The patient was successfully treated with neoadjuvant denosumab therapy, which allowed curettage. In addition, the pulmonary nodule reduced in size following denosumab administration, and surgical resection was performed. Since the operation, the patient has been managed with the continued use of denosumab with no sign of recurrence. Microscopic findings from the surgical specimen following denosumab treatment revealed that the giant cells had disappeared and woven bone had formed. The specimen from the pulmonary nodule exhibited similar findings to the surgical specimen. It was reported that denosumab treatment was able to reduce the number of giant cells and RANK-positive stromal cells, and cause the formation of new bone in the primary lesion. The present study reports the first case to demonstrate the efficiency of denosumab in treating pulmonary metastasis of GCTB.
authors: Division of Orthopedic Surgery, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8510, Japan.
authors: Tetsuro
authors: T
authors: Yamagishi
authors: Division of Orthopedic Surgery, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8510, Japan.
authors: Hiroyuki
authors: H
authors: Kawashima
authors: Division of Orthopedic Surgery, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8510, Japan.
authors: Akira
authors: A
authors: Ogose
authors: Division of Orthopedic Surgery, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8510, Japan.
authors: Taro
authors: T
authors: Sasaki
authors: Division of Orthopedic Surgery, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8510, Japan.
authors: Tetsuo
authors: T
authors: Hotta
authors: Division of Radiology, Niigata University Medical and Dental Hospital, Niigata 951-8510, Japan.
authors: Shoichi
authors: S
authors: Inagawa
authors: Division of Pathology, Niigata University Medical and Dental Hospital, Niigata 951-8510, Japan.
authors: Hajime
authors: H
authors: Umezu
authors: Division of Orthopedic Surgery, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8510, Japan.
authors: Naoto
authors: N
authors: Endo
keywords: bone formation; denosumab; giant-cell tumor of the bone; metastasis; receptor activator of nuclear factor κB ligand