A Rare Cause of Ascites in a Young Woman Mimicking Peritoneal Carcinomatosis.

Peritoneal granulomatous reaction to foreign body-like materials of a dermoid cyst is a rare condition and has always been challenging in diagnosis for physicians. Macroscopic view of granulomatous peritoneum, which mimics peritoneal carcinomatosis or peritoneal seeding originating from ovarian carcinoma, necessitates a detailed microscopic evaluation of peritoneum, which shows multinucleated giant cells and granuloma formation indicating a foreign body reaction in the peritoneum. To avoid unnecessary radical surgeries and salvage chemotherapies in these patients, a detailed microscopic evaluation of their peritoneum is necessary. The present study introduces a 23-year-old woman with new-onset ascites and an elevation of CA125 level suspicious of ovarian carcinoma but with a peritoneal microscopic finding pathognomonic of foreign body reaction.