Breast cancer in male patients is a rare clinical entity, representing less than 1% of all cancer incidence in males. Breast cancer is highly associated to hyperestrogenism, obesity and alcohol intake, and it is a disease mostly considered in female patients, hence, the lack of suspicion and proper evaluation in male patients. It must be considered that these tumors may be malignant and require an adequate protocol to avoid establishing diagnosis in advanced stages. This is the case of a 19-year-old male in Mexico City, who was diagnosed with a fibromixoid sarcoma, based on mastography and ultrasound imaging, biopsy and immunohistochemical signature. Tumor was excised through radical left breast mastectomy with final histologic diagnosis being fibromixoid sarcoma (T2a N0 M0), clinical stage IB. No further treatment was required, and periodical outpatient consultations are performed for follow up. The most significant risk factor found in our patient was an increased body mass index (BMI), smoking and alcohol consumption.