Rapidly progressing malignant phyllodes tumor of the prostate with normal prostate-specific antigen levels: A case report.

Malignant phyllodes tumor of the prostate is a very rare entity. Here, we describe a 51-year-old patient with a malignant phyllodes tumor of the prostate with a poor prognosis and normal prostate-specific antigen levels. Digital rectal examination revealed a hard, nodular mass in the prostate, and magnetic resonance imaging exhibited a cystic mass measuring 8.7 cm × 7.0 cm × 6.7 cm. Immunohistochemical staining showed that the epithelial components were positive for CK8/18 and cytokeratin AE1/AE3; the atypical stromal cells were positive for CD34 and vimentin. Histological analysis resulted in a diagnosis of malignant phyllodes tumor of the prostate. Radical surgery was the treatment of choice. However, tumor recurrence was identified 6 months after the surgery, and the patient died 10 months after the surgery.