[A Case of Low-Grade Appendiceal Mucinous Neoplasm with Extra-Appendiceal Mucin Extrusion Successfully Treated with Laparoscopic Surgery].

A 49-year-old male patient, who presented with abdominal pain, was suspected of having acute appendicitis. Abdominal computed tomography revealed a swollen appendix, accompanied by a 40 mm low-density mass located behind the appendix. He was diagnosed with an appendiceal mucinous neoplasm, and laparoscopic ileocecal resection was performed. A soft tumor was found proximal to the swollen appendix and was adhered tightly to the iliopsoas muscle. The tumor cells were exfoliated carefully, and the tumor was excised en bloc without any injury. Histopathological examination revealed a low- grade appendiceal mucinous neoplasm(LAMN)accompanied by extra-appendiceal mucin extrusion due to the lack of epithelial lining. Because LAMN is potentially malignant, surgical excision was performed as first-line therapy. In the surgical management of LAMN, preventing intraoperative rupture is essential to avoid pseudomyxoma peritonei. To achieve this, a magnified laparoscopic surgery may be useful. Although no definitive guidelines describing the indications of lymph node dissection or the appropriate extent of resection exist, laparoscopic ileocecal resection may be used to manage cases of LAMN.