A 79-year-old man had undergone surgical implantation of a femoral prosthesis necessitated by metastasis of squamous cell carcinoma of unknown primary origin, which had caused a pathologic fracture in the left femur neck. One year after surgery, a mass was discovered in the patient's left hip that was accompanied by swelling and pain in the entire left leg. A computed tomographic (CT) scan of the pelvis and a bone scan were followed by TI-201 imaging, which excluded the possibility of local infection. Biopsy of the palpable mass in the left hip confirmed local metastatic invasion of squamous cell carcinoma of unknown primary origin in the left femur neck. The patient died 2 months after this diagnosis.