Case reports: Osteogenic sarcoma of the patella spread to lateral meniscus after arthroscopy.

Our patient presented with a rare lesion, a patella osteogenic sarcoma that spread to the anterior horn of the lateral meniscus via the arthroscope. He was treated arthroscopically for a torn medial meniscus of his right knee. A lesion in the patella was observed and a biopsy specimen was obtained through the arthroscope. The specimen was diagnosed as an osteogenic sarcoma. After 2 weeks of neoadjuvant chemo-therapy, the patient refused additional chemotherapy. Re-section of the knee and allograft arthrodesis were done 4 months after the initial arthroscopy. Pathologic examination of the resected specimen showed osteogenic sarcoma of the patella and a completely separate 1.0-cm nodule of osteogenic sarcoma tissue growing in the anterior horn of the lateral meniscus. The patient died 15 months after knee re-section with multiple pulmonary metastases. We are unaware that such an occurrence of an osteosarcoma spread through an arthroscope has been documented pathologically and reported.