Necrotic pseudoxanthomatous nodules of the omentum and peritoneum: A peculiar reaction to endometriotic cyst contents

BACKGROUND: Necrotic pseudoxanthomatous nodules of the ovary, omentum, and peritoneum are rare, and have been described as a late manifestation of endometriosis. CASE: A 39-year-old woman presented with acute abdominal pain and an abdominopelvic mass. Emergency laparotomy revealed a ruptured ovarian neoplasm with several liters of old blood in the abdominal cavity. Left adnexectomy was performed, and exploration of the abdominal cavity revealed no other lesions. Pathologic examination of the neoplasm showed a large endometrioma with an associated endometrioid adenocarcinoma. At surgery 7 weeks later, multiple pseudoxanthomatous peritoneal and omental nodules were found. CONCLUSION: This case suggests that pseudoxanthomatous nodules of the peritoneum and omentum may arise from a peculiar reaction to endometriotic cyst contents and clinically can mimic metastatic ovarian carcinoma.