Malignant peritoneal mesothelioma mimicking ovarian cancer: a diagnostic challenge

Malignant peritoneal mesothelioma (MPM) is a rare and aggressive cancer associated with a poor prognosis. Its presentation mimics a spectrum of conditions, making diagnosis and management particularly challenging. This case highlights the difficulties in managing MPM under the constraints of diagnostic uncertainty. A nulliparous woman in her early 20s was initially diagnosed with ovarian cancer based on CT imaging, leading to laparotomy for tumour debulking with fertility-sparing procedures. However, the postoperative diagnosis of MPM necessitated reoperation for cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC), which resulted in favourable outcomes. This case underscores several important points: (1) The limitations of imaging in distinguishing MPM from ovarian cancer, (2) The critical role of pathological diagnosis, including immunohistochemical staining, in differentiating between benign and malignant mesothelioma, (3) The utility of grading MPM risk using clinical findings, the peritoneal cancer index and pathological results to guide decisions regarding subsequent neoadjuvant chemotherapy and (4) The challenges in managing a rare and aggressive malignancy, which demonstrated a favourable response to CRS-HIPEC.