Primary breast sarcomas are rare tumors, accounting for about 1% of all malignant breast cancers. Breast leiomyosarcoma are extremely rare and only 28 well doccumented cases have been reported.The mean age of reported cases is 54 years. We presente a 20 year old woman with large right breast mass. Histological exammination reveled high grade sarcoma with pleomorphic spindle cells, hyperchoromatic nuclei, frequent mitoses and extensive necrosis. The tumor cells were positive for desmin, smooth muscle actin and vimentin and negative for cytokeratin, EMA and S-100 Protein. Axillary lymph nodes were free of tumor. Our patient is the youngest reported case of breast leiomyosarcoma in English literature .

Keywords: Breast; Sarcoma; Leiomyosarcoma