Giant Mucinous Borderline Ovarian Tumor With Microinvasion Presenting As Massive Ascites and Acute Respiratory Compromise: A Case Report

A 34-year-old nulligravida with schizophrenia presented after four months of progressive abdominal distension, culminating in severe respiratory compromise. An urgent transabdominal ultrasound was initially interpreted as massive ascites; however, its diagnostic accuracy was limited by the extreme abdominal distension and the patient's inability to change position due to respiratory distress. Further evaluation with CT of the thorax and abdomen revealed a 35 × 42 × 48.5 cm cystic mass arising from the left ovary, causing marked thoracoabdominal compression. Laboratory studies demonstrated leukocytosis, elevated inflammatory markers, and increased carcinoembryonic antigen and carbohydrate antigen 19-9, consistent with an ovarian neoplasm. An urgent midline laparotomy permitted controlled decompression of 37 L of serosanguinous fluid and en bloc resection of the ovarian mass, relieving the patient's respiratory distress. Histopathology identified a mucinous borderline tumor with focal intraepithelial carcinoma, microinvasion (<5 mm), and an incidental benign Brenner component. After an uneventful recovery, the patient elected definitive management and underwent total hysterectomy with right salpingectomy one month later. At six-month follow-up, she remained in good health without evidence of recurrence.