Intratumoral hemorrhage of mammary phyllodes tumor after menstrual induction: a puzzling presentation.

BACKGROUND Mammary phyllodes tumor is an uncommon stromal-epithelial neoplasm with a reported incidence of 0.3% to 0.5% of female breast tumors. Sudden, rapid growth of a mammary phyllodes tumor with intratumoral hemorrhage was noted in a 45-year-old woman after menstrual induction with progesterone and norethindrone acetate. This case is presented here to highlight the possibility of such an onset of phyllodes tumor in order to facilitate its prompt diagnosis. CASE PRESENTATION A 45-year-old woman suffered from missed periods for 2 months and received progesterone for menstrual induction. After treatment, rapid enlargement of her left breast was noted. Tracing the history of the patient, we found that she had already felt an about 3 cm painless lump in her left breast 5 months before this episode. Sonography of the left breast showed a large cystic lesion with some echogenic content and about 150 mL of old blood was obtained by aspiration. Surprisingly, follow-up breast sonography 3 weeks later revealed a large irregular solid mass and a small amount of peripheral cystic content with markedly increased vascularity. Surgery was suggested. A large encapsulated mass consisting of heterogeneous yellow soft tissue and a cystic component measuring 10 x 8 cm was totally excised. Microscopically, the sections revealed branching and cystically dilated glands lined by cuboidal to columnar epithelial cells in a myxoid hypercellular fibroblastic stroma with hyperchromatic nuclei and frequent mitotic figures. The final histological diagnosis was malignant phyllodes tumor. CONCLUSION Progesterone for menstrual induction may cause rapid growth of a phyllodes tumor with resultant internal hemorrhage. Only with the awareness of this entity can a prompt diagnosis be made and optimal treatment be given.