Rationale: Adult spinal epidermoid cyst (SEC) is a rare tumor. Lumbar laminectomy and tumor removal was a routine surgical procedure for adult spinal epidermoid cyst according to the literature, but postoperative lumbar instability and intractable low back pain may occur. In this study, we presented a brief report of an adult lumbar epidermoid cyst and introduced another surgical approach. Patient concerns: This 28-year-old woman has been complaining of the severe right buttock pain and right thigh radiating pain for half a year. She had been diagnosed as sacroiliitis, spinal arthritis, and lumbar disc herniation at 3 different hospitals before coming to our hospital. And she received a variety of conservative treatments, including non-steroidal anti-inflammatory drugs, aspirin, acetaminophen, glucocorticoids, acupuncture, physical therapy, and so on. However, her pain did not diminish at all. Finally, we find a space-occupying lesion in her lumbar magnetic resonance images (MRI). The lesion was slightly low, equal, and uneven equal-low signals on T1WI. T2WI showed slightly higher, equal, and uneven equal-high signals. And a thin-rim enhancement was observed on Gd-DTPA-enhanced MRI. Diagnoses: Adult spinal epidermoid cyst. Interventions: The patient underwent a surgery of lumbar laminectomy, tumor excision, and spinous process-vertebral plate in situ replantation. Outcomes:Postoperative pathology prompted that the tumor was cystoid. The patient's symptoms were completely removed 1 week after surgery. Three-month postoperative MRI confirmed that the spinal epidermoid cyst had been completely removed and three-dimensional CT prompted lumbar lamina in situ. Bony fusion occurred at 6 months after the surgery. Lessons:Lumbar laminotomy and replantation provides an ideal option to treat adult spinal epidermoid cyst because it can completely remove the cyst and simultaneously reduce the risk of iatrogenic lumbar instability.