Stress fractures in systemic lupus erythematosus after long-term MTX use successfully treated by MTX discontinuation and individualized bone-specific therapy

We report the case of a 64-year-old woman with systemic lupus erythematosus (SLE) and recurrent bilateral stress fractures of the calcaneus due to long-term methotrexate (MTX) use. A detailed skeletal assessment pointed to osteoporomalacia with pronounced trabecular thinning and increased bone resorption. After years of unsuccessful treatment with bisphosphonates, a combined bone-specific denosumab-teriparatide treatment was initiated, and additional belimumab treatment was started to avoid intermittent steroid usage. As these measures did not lead to a significant improvement of the bone situation, MTX was eventually discontinued. This was followed by a rapid clinical improvement. In a follow-up MRI scan after 18 months, the stress fractures had almost disappeared. Furthermore, the bone density and microarchitecture markedly improved. In conclusion, this case demonstrates that MTX discontinuation/replacement in combination with an individualized and state-of-the-art bone-specific therapy is effective in SLE patients with stress fractures after long-term MTX use.