Chondroblastic osteosarcoma of breast in a case of phyllodes tumour with recurrence, a rare case report

INTRODUCTION: Primary extra osseous osteogenic sarcomas have been reported in many tissues of the body but their occurrence in the breast is extremely rare. It can arise as a result of osseous metaplasia in a pre-existing benign or malignant neoplasm of the breast. CASE PRESENTATION: A 24 year-old young lady was diagnosed to have mass in right breast.Tru cut biopsy showed it was malignant phyllodes tumour. There was no distant metastasis or any axillary lymph nodes palpable. Simple mastectomy was done. The histology report of biopsy showed a malignant phyllodes with chondrosarcomatous differentiation an myxoid changes. She was given 6 cycles of chemotherapy. There was recurrence after 6 months of surgery. Then radical mastectomy with latissimus dorsi musculocutaneous flap was used to cover the anterior chest wall defect. Sections from the mastectomy specimen confirmed the diagnosis of chondroblastic osteosarcoma. Axillary nodes free of tumour cells. Now the patient again came with recurrence after 5 months, and disseminate subcutaneous nodules. CONCLUSION: A diagnosis of chondroblastic osteosarcoma of the breast was made based on histology report and after excluding any osteogenic sarcoma arising from underlying ribs and sternum. It is a very rare disease with only few case reports in literature.