Objective <p>To describe an unusual cause of thigh myopathy and nerve compression in a patient with systemic lupus erythematosus (SLE), illustrating the importance of interdisciplinary collaboration.</p> Case presentation <p>A 26-year-old woman with a 10-year history of SLE presented with new-onset right thigh pain and restricted hip movement. Knee pathology was excluded, and symptoms were initially attributed to hydroxychloroquine treatment. Despite conservative management, pain worsened. MRI revealed multifocal myositis in the gluteal and adductor regions with signal changes in the sciatic nerve and enlarged groin lymph nodes. Repeated histopathological, neurological, and radiological examinations remained inconclusive until a pelvic MRI showed bilateral lymphadenopathy along the lumbar plexus, compressing the obturator nerve.</p> Results <p>Treatment with high-dose prednisolone led to rapid clinical improvement with resolution of pain and restoration of hip mobility, accompanied by radiological resolution of muscular and nodal changes.</p> Conclusion <p>This case demonstrates an uncommon manifestation of active SLE with pelvic lymphadenopathy causing obturator nerve compression and secondary thigh myopathy. Early interdisciplinary evaluation was essential for diagnosis and management in this complex autoimmune presentation.</p>