Supplementary Material for: Primary Angiosarcoma of the Ovary: A Case Report and Literature Review

Introduction: Primary angiosarcoma of the ovary is an exceptionally rare and aggressive malignancy, representing a diagnostic and therapeutic challenge. Due to its rarity, standardized management protocols are lacking, and prognosis remains poor. Case Presentation: A 45-year-old woman with diabetes and hypertension presented with abdominal pain and a palpable pelvic mass. Imaging revealed a complex right adnexal mass. She underwent total abdominal hysterectomy with bilateral salpingo-oophorectomy. Histopathological examination revealed a high-grade pleomorphic tumor. Immunohistochemistry was pivotal for diagnosis, showing strong positivity for CD31 and ERG, and negativity for epithelial markers, confirming a primary pure ovarian angiosarcoma (FIGO Stage II). Postoperative PET-CT showed no distant metastasis. Following a multidisciplinary tumor board review, she received four cycles of adjuvant carboplatin and paclitaxel. At six-month follow-up, she remained asymptomatic with no evidence of recurrence. Conclusion: This case underscores the importance of a comprehensive immunohistochemical panel in diagnosing rare ovarian malignancies, particularly to distinguish angiosarcoma from other poorly differentiated tumors. Multidisciplinary management is essential. While adjuvant chemotherapy may offer benefit, the prognosis for advanced-stage ovarian angiosarcoma remains guarded. This report adds to the limited literature on this entity and highlights the need for further research to establish optimal treatment strategies.