Primary sarcomas of the breast are heterogeneous neoplasms derived from the non-epithelial elements of the mammary gland. Malignant peripheral nerve sheath tumors comprise 5–10% of all malignant soft tissue sarcomas. Its heterogeneity and low incidence (1 in 100,000) limit the performance of prospective studies. Therefore, most published articles include individual reports and case series with a small number of patients, making it impossible to determine clear treatment standards in this scenario. A 36-year-old young woman with no personal history consulted the National Cancer Institute of Colombia with a 1-year progression of a rapidly growing mass in her left breast until reaching an approximate tumor size of 20 × 20 cm. Histopathological analysis with a tru-cut biopsy taken from the lesion revealed the presence of a breast sarcoma with positive staining for SOX-10 and S-100. A radical mastectomy as her first treatment included the resection of a costal arch and, therefore, the reconstruction of the chest wall with coverage of the defect with an extended latissimus dorsi flap followed by consolidation therapy with adjuvant radiotherapy (RT) and chemotherapy. Evidence regarding malignant peripheral nerve sheath sarcoma of the breast treatment corresponds to retrospective analyses and case reports with high heterogeneity and variability about strategies in surgical procedures and adjunctive therapy such as complementary chemotherapy and RT; therapeutic approach should always include a multidisciplinary team.