BackgroundLangerhans cell histiocytosis (LCH) in adult lumbar spine is extremely rare, and optimal treatments remain unclear. In literature, only a few cases of lumbar spine LCH were treated using surgery but en bloc vertebral resection has not been used.Case presentationA 50-year-old man presented with unbearable radiating pain at his right leg. Radiological studies revealed a solitary osteolytic lesion, which was moderately enhanced on contrast MR imaging and hyper-metabolic on PET/CT, at the right L5 vertebral body and arch. In biopsy, Langerhans cells were observed, but findings were insufficient to establish a diagnosis of LCH. A modified L5 en bloc vertebral resection via anterior and posterior approaches was performed to remove the right 2/3 portion of the L5 vertebra. The left 1/3 vertebral body and left pedicle of L5, which were not affected, were kept in situ to allow short instrumentation and reconstruction. His leg pain disappeared after the surgery, and a precise diagnosis of LCH was established after a throughout histological study of the removed vertebra. The patient further accepted 1 cycle of low-dose radiotherapy postoperatively. At 18-month follow-up, the lumbosacral spine was fused and no local reoccurrence was noticed.ConclusionsFor lumbar spine LCH, surgery should be considered if there are neurological symptoms or histological diagnosis is indefinite in biopsy. En bloc vertebral resection can be used to alleviate neurological symptoms and prevent local reoccurrence.