RESUMEN
Gestational breast cancer is the most common cause of cancer in pregnant women. It is a challenging condition for the medical team, since the physiological changes in the breast during this period increase the density of the breast parenchyma, which makes it difficult to detect the nodule on physical and imaging examination, causing delay in diagnosis. We present here a case report of a woman with breast cancer diagnosed during pregnancy. This was a 28-year-old female patient who arrived at the service at 14 weeks' gestation, diagnosed with invasive ductal carcinoma in the left breast, with T4dN2M0 staging. Neoadjuvant chemotherapy treatment was started with a pause for the cesarean section at 36 weeks' gestation. After delivery, chemotherapy was restarted, followed by radical mastectomy, radiotherapy and hormone therapy. Two years after the initial diagnosis and still being treated with hormone therapy, the patient presented with musculoskeletal pain, detected on magnetic resonance imaging and bone scintigraphy, as well as several points of metastasis in the spine with pathological fracture of L2-L3, where she was then submitted to decompressive laminectomy. After surgery, radiotherapy of the thoracic and lumbar spine was started, in addition to chemotherapy. Currently, the patient is asymptomatic, being on paclitaxel and transtuzumab, with stable bone scintigraphy and radiography and ultrasound showing no metastases, and the child is healthy after three years of follow-up.