胸椎に発生したランゲルハンス細胞組織球症の1例

We report a 2-year-old girl with solitary Langerhans cell histiocytosis (LCH) of the thoracic spine causing spinal compression. She presented with a 2-month history of back pain. CT and MRI demonstrated collapse of the 4th thoracic vertebral body, resulting in a so-called "vertebra plana". This lesion also involved a soft tissue mass that extended to the thecal space and compressed the thecal sac. These findings indicated an oncologic emergency and we immediately performed a CT-guided biopsy to confirm the histopathological diagnosis of LCH by demonstration of S-100 and CD1a immunoreactive cells. There has been some debate on the appropriate care of single-system single-site LCH and a consensus has not yet been established. In this case, we subsequently initiated chemotherapy according to the JLSG-02 protocol of the Japan LCH study group. The child soon achieved remission through chemotherapy, but the vertebra plana remained unchanged despite relief from back pain. The presence of limitations in her daily activities prompted us to perform a pamidronate trial. After a 6-month course of chemotherapy, she received intravenous administration of pamidronate 1mg/kg/day on each of three consecutive days once every 3 months. Two cycles of pamidronate treatment has promoted repair of the collapsed vertebral body without severe side effects. Pamidronate therapy may be effective for LCH patients with osteoclastic lesions.