Synchronous multifocal osteosarcoma: Report of 4 cases and literature review

Background

Multifocal osteosarcoma (MFOS) is rare, accounting for approximately 1.5 % of osteosarcomas, and can be synchronous (lesions within six months) or metachronous (lesions after six months). The etiology and optimal treatment for MFOS remain controversial. This report presents four patients with synchronous MFOS and reviews the literature.

Case presentation

Case 1: A 24-year-old female with low back pain was found to have multiple lytic bone lesions with increased FDG uptake in the vertebral column and pelvic bones. Biopsy confirmed osteoblastoma-like osteosarcoma. After chemotherapy, she is alive after 5 months.

Case 2: A 6-year-old girl with right knee pain had a distal femur mass and a calcified inguinal lesion. Biopsies revealed osteoblastic osteosarcoma with metastatic lymph node involvement. Following chemotherapy and surgeries, she experienced recurrence and required further surgery. She is alive after 21 months.

Case 3: A 4-year-old boy with a walking disability had a sclerotic bone lesion in the distal femur and additional lesions in the pelvis and acetabulum. Biopsy confirmed osteoblastic osteosarcoma. Despite treatment, he developed metastases and died 7 months after diagnosis.

Case 4: A 9-year-old girl with right knee swelling had a sclerotic lytic lesion in the distal femur and an acetabular lesion. Biopsies confirmed chondroblastic osteosarcoma. After chemotherapy and surgery, she experienced recurrence and underwent pelvic resection. She died 24 months after diagnosis.

Conclusion

Synchronous MFOS is a highly aggressive osteosarcoma variant with a poor prognosis. Aggressive, individualized treatment may improve outcomes, particularly in metachronous cases. Further research is needed to enhance understanding and management of this rare condition.