Periprosthetic metastasis following total hip arthroplasty in a patient with lung carcinoma: A case report and review of literature.

RATIONALE: Periprosthetic osteolysis secondary to septic loosening and aseptic loosening is a well-described phenomenon associated with artificial hip arthroplasty. Periprosthetic bone loss as a result of metastatic infiltration is an uncommon cause of early, progressive loosening of joint replacement prosthesis and is rarely described in the literature.

PATIENT CONCERNS: The present study describes a 70-year-old male patient who was diagnosed with pulmonary squamous cell carcinoma 5 years after total hip arthroplasty (THA) and developed a metastasis from squamous cell carcinoma in the periprosthetic neosynovial tissue 1 year after formal chemotherapy. The main complaint was hip pain with limited activity for about 3 months.

DIAGNOSES: Expansive bone destruction and periprosthetic osteolysis at the right femoral trochanter were identified through X-ray and Tc bone scan. The diagnosis of pulmonary squamous cell carcinoma metastasis was finally confirmed on the basis of postoperative pathological examination.

INTERVENTIONS: The patient underwent open surgery with proximal femoral prosthesis revision and tumor prosthesis resection to completely remove the tumor tissue and relieve pain.

OUTCOMES: The patient was completely relieved of pain at discharge 2 weeks after surgery and experienced no complications. However, the patient died of respiratory failure due to disease progression 3 months after surgery.

LESSONS: We believe that clinicians should maintain a high index of suspicion and consider metastatic disease in differential diagnosis of cases of aseptic loosening, particularly if the patient has a history of malignant disease and the osteolytic lesion involves the outer cortex. In addition, patients with a known history of malignancy should be screened with a pre-operative bone scan to rule out any metastatic infiltration and regularly followed up at short intervals to detect any early bone loss.