Introduction: Giant cystadenocarcinomas of the ovary are rarely described conditions.
Case presentation: The authors describe a 57-year-old Brazilian woman who presented with an increase in abdominal girth in February 2003. Imaging studies showed a giant abdominal pelvic mass with probable origin in the right ovary. Cancer antigen-125 was elevated, while carcinoembrionic antigen and alpha-fetoprotein were normal. Total abdominal hysterectomy, bilateral salpingoophorectomy and omentectomy were done. The mass weighed 40Kg, and the histopathology study revealed a mucinous cystadenocarcinoma. She underwent chemotherapy with paclitaxel and cisplatin with no side effects. Under follow-up for more than 10 years, she is asymptomatic and with normal imaging and laboratory parameters, including the cancer antigen-125 marker.
Conclusion: This huge tumor evolved for a long time unsuspected and without metastases in a patient from a developing region. The diagnostic and management challenges posed by this unexpected and unusual presentation of an ovarian cystadenocarcinoma are discussed.