Benign multicystic mesothelioma of appendiceal origin treated by hyperthermic intraperitoneal chemotherapy: A case report

INTRODUCTION AND IMPORTANCE: Peritoneal benign cystic mesothelioma is a rare benign tumor that originates from a mesothelial proliferative lesion of the peritoneum. However, proper surgical management remains unclear due to its low incidence. We report a clinical case of peritoneal benign cystic mesothelioma treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). CASE PRESENTATION: A 60-year-old female who underwent laparoscopic appendectomy in 2015 presented with abdominal pain in right lower quadrant area. Computed tomography of the abdomen and pelvis revealed a ruptured appendiceal mucocele or mucinous neoplasm, and several seeding-like small nodules in the greater omentum and right peritoneum. Cytoreductive surgery followed by HIPEC was performed; right hemicolectomy and lymph node dissection, omentectomy, and right abdominal partial peritonectomy. HIPEC with mitomycin was conducted for 90 min and an anastomosis between the ileum and colon was made after HIPEC. The pathologic results revealed the colonic mass was a multi-loculated cyst lined by mesothelial cells containing amorphous eosinophilic fibrinoid material, which are common features of benign cystic mesothelioma. CLINICAL DISCUSSION: Peritoneal benign cystic mesothelioma is known as a borderline disease of mesothelial tumors. Because its etiology is unknown, treatment strategies are not determined. CONCLUSION: Cytoreductive surgery followed by HIPEC can be considered to treat peritoneal benign cystic mesothelioma and prevent its malignant transformation.