Fatal outcome of malignant phyllodes tumor of the breast in pregnancy: a case and literature review.

Phyllodes tumor of the breast (PTB) is a rare fibroepithelial breast neoplasm that accounts for less than 1% of breast tumors. Only a few cases related to pregnancy have been reported. It is not known how pregnancy affects the diagnosis, treatment and prognosis of breast tumors. Here we report a case of a 38-year-old female patient with a small, mobile palpable lump in the left breast for about 15 years. it was considered a benign lesion and no surgical treatment was performed at the beginning. The left breast mass became larger suddenly during pregnancy, However, she did not see the doctor and receive any treatment in time. The lump was resected one year after labor and confirmed to be malignant phyllodes of the breast by histopathology and immunohistochemistry. Unfortunately, local recurrence occurred within six months after the first operation, and lung metastasis occurred eight months later. And this patient finally died 13 months after the operation due to tumor progression. This is the first report of pregnancy-related malignant PTB, with local recurrence and distant metastasis in a short period. This case report highlights a situation: the patient should be diagnosed early and treated in time when she has a previous breast fibroadenoma, but suddenly increased during pregnancy.