Patient with metastatic adenocarcinoma imitating lumbar herniated nucleus pulposis.

Objective: To highlight the utility of Cyriax's selective tissue-tensioning principles, specifically the "Sign of the Buttock," in identifying mechanical behavior of pain of pathologies not amenable to conservative treatment.

Clinical Features: A 41-year-old man was referred to the University of Pittsburgh Medical Center Spine Specialty Center with a diagnosis of L5-S1 herniated nucleus pulposis that was recalcitrant to treatment. The onset of symptoms had been 5 months before the patient's appointment at the Spine Center and 6 months after an apparent precipitating trauma. The patient had been followed up by his primary care physician, referred to urology, neurosurgery, and physical medicine and rehabilitation before being referred to the Spine Specialty Center.

Intervention And Outcome: Clinical examination using Cyriax's Sign of the Buttock implicates the hip joint, while it helps to rule out the lumbar spine. Review of previous imaging studies failed to rule out hip pathology. Pelvis and hip magnetic resonance imaging led to suspicion of lytic lesions, and a diagnosis of metastatic adenocarcinoma was made via biopsy.

Conclusion: We have found Cyriax's Sign of the Buttock to have diagnostic value in this case. When positive, this test may help identify serious extracapsular hip or pelvic pathology.