TITLE:
A Rare 40-cm Retroperitoneal Isolated Enteric Duplication Cyst Mimicking an Ovarian Neoplasm: A Case Report
AUTHORS:
Kyousuke Takeuchi, Risa Asami, Ai Yoshida, Yui Yamasaki, Makoto Sugimoto, Tsuyoshi Ishida, Hiroshi Hasegawa, Yoshihiro Kakeji
KEYWORDS:
Isolated Enteric Duplication Cyst, Ovarian Tumor Mimic, Giant Abdominal Cyst, Tumor Marker Elevation, Surgical Diagnosis
JOURNAL NAME:
Open Journal of Obstetrics and Gynecology,
Vol.15 No.8,
August
18,
2025
ABSTRACT: Background: Isolated enteric duplication cysts (IEDCs) occurring in the retroperitoneum are extremely uncommon, and reports of those exceeding 40 cm in size are exceptionally rare. Diagnosing such lesions preoperatively remains difficult, especially when they mimic ovarian tumors. Case presentation: We present a 37-year-old woman (G3P3) with acute abdominal distension and pain. Radiologic imaging identified a 40-cm multiloculated cystic lesion containing calcifications and fat, initially suggestive of a giant mature teratoma with hydrosalpinx. Tumor markers (CA125, CA19-9, CEA) were elevated. Exploratory laparotomy revealed a smooth, large cystic mass that occupied the entire peritoneal cavity, and a small incision allowed for cyst drainage. The aspirated cystic fluid exhibited features consistent with intestinal contents, and the inner wall of the cyst demonstrated a mucosa-like appearance reminiscent of intestinal epithelium. Upon decompression, the uterus and adnexa appeared normal, and the mass was found to originate from the retroperitoneum adjacent to the descending colon. Histological evaluation established the diagnosis of a retroperitoneal IEDC. The lesion was excised completely one month later. One-year follow-up showed no recurrence. Conclusion: This case underscores the diagnostic complexity of massive retroperitoneal cystic tumors, the value of intraoperative assessment, and expands the clinical spectrum of giant IEDCs.