Angiosarcoma as Homologous Mesenchymal Component of Ovarian Malignant Mixed Mullerian Tumor: A Case Study

Background: Malignant mixed Mllerian tumor (MMMT) or carcinosarcoma of the female genital tract is a rare but highly aggressive malignancy.Case presentation: We report a unique case of primary ovarian MMMT with poorly differentiated angiosarcoma as its homologous sarcomatous component in a 53-year-old woman with a known germline BRCA1 mutation who presented with a pelvic mass.She underwent staging cytoreduction surgery including total hysterectomy, bilateral salpingo-oophorectomy, omentectomy, and pelvic and para-aortic lymph node dissections.The removed right ovarian tumor formed a 2.5 cm nodular to cystic mass replacing the entire organ.Microscopic examination revealed two distinct tumor components: high-grade serous carcinoma and poorly differentiated angiosarcoma.The proliferating sarcomatous cells were diffusely positive for CD31 and Factor VIII, but were negative for 100, SOX10 and cytokeratin.Both the serous carcinoma and angiosarcoma components demonstrated aberrant strong and diffuse p53 nuclear positivity.KRAS mutation analysis revealed guanine-adenine-thymine point mutation at codon 12 in both tumor components.Metastatic tumor was found involving the contralateral left ovary with the cellular composition of pure angiosarcomatous component.Conclusions: This is the first report of an ovarian MMMT with angiosarcoma as its homologous sarcoma component.The presence of aberrant p53 expression and identical KRAS mutation in both the serous carcinoma and angiosarcoma components supports the theory of malignant mesenchymal transition/metaplasia in the development of MMMT.