Incidental low-grade appendiceal mucinous neoplasm discovered during emergency caesarean section: a case report

Abstract

Low-grade appendiceal mucinous neoplasm (LAMN) is a rare epithelial tumour, often discovered incidentally. The condition is of particular concern due to its potential to cause pseudomyxoma peritonei (PMP). LAMN in pregnancy is exceedingly rare, with only a limited number of cases reported. Its diagnosis is often challenging due to the physiological changes of pregnancy, which can obscure symptoms and delay detection. We present a case of a 22-year-old female who underwent an emergency lower-segment caesarean section (LSCS) at 39 weeks gestation due to failure to progress and foetal distress. Intraoperatively, the peritoneal cavity contained copious mucinous material, and an enlarged, erythematous appendix was noted. The general surgical team were consulted and performed an appendicectomy, and histopathological examination confirmed LAMN with acellular mucin deposition on the serosal surface. Cytological analysis of the peritoneal fluid was negative for epithelial cells. Postoperative surveillance included tumour marker assessment, colonoscopy, and staging imaging, all of which showed no evidence of peritoneal dissemination. A follow-up diagnostic laparoscopy at six months confirmed the absence of disease progression. This case highlights the challenges of diagnosing LAMN in pregnancy and underscores the importance of intraoperative vigilance during caesarean sections. Given the potential for peritoneal spread, structured long-term surveillance is critical. Early recognition and appropriate management can help prevent complications such as PMP and improve patient outcomes.