2018 年 34 巻 2 号 p. 229-232
We report a case of left mucinous borderline ovarian tumor and right ovarian and tubal absence. A 36-year-old patient felt discomfort in her lower abdomen and visited our hospital for further examination. Magnetic resonance imaging (MRI) revealed an approximately 16-cm multilocular tumor. The tumor of the right ovary was extracted via laparoscopically assisted cystectomy. Intraoperatively, we noticed the absent left adnexa. Pathological examination revealed that the right ovarian tumor was a mucinous borderline tumor. During the follow-up, no postoperative recurrence was observed. Two causes have been identified for congenital absence of unilateral ovary and fallopian tube, namely congenital developmental defect and torsion of the adnexa. The present case likely resulted from an asymptomatic torsion because of the absence of other genitourinary anomalies and the strong adherence of the left fallopian tube angle to the sigmoid colon despite that the patient had no surgical history.