Successful extended surgery for mucinous cystadenocarcinoma of the appendix with the right iliopsoas muscle invasion

A 52-year-old man presented with a chief complaint of abdominal distension. Contrast-enhanced abdominal CT showed a 5 cm cystic mass on the cecum that invaded into the right iliopsoas muscle. Colonoscopy showed a protruding tumor on the cecum, and the biopsy specimens revealed adenocarcinoma. Therefore, the patient was given a diagnosis of mucinous cystadenocarcinoma of the appendix with right iliopsoas muscle invasion. Chemotherapy was planned as initial treatment at the previous hospital. However, the patient sought a secondopinion surgical treatment at Tohoku University Hospital. Although the tumor invaded into the right iliopsoas muscle, it was localized without any evidence of additional distant metastases. Therefore, surgical intervention was chosen for his initial treatment at our institution. The tumor was curatively removed by ileocecal resection with partial resection of the right iliopsoas muscle and the right femoral nerve (pT4b, pN0, pM0, pStage II). Complications of the operation were limited to difficulty of right knee extension, which subsequently resolved with post-operative rehabilitation. The patient is now able to walk; he is disease-free, without any signs of recurrence at 20 months post-operation. There is no evidence of effective chemotherapy for advanced mucinous cystadenocarcinoma of the appendix in the literature. Therefore, we present a curative treatment option via extensive surgical resection for patients with advanced mucinous cystadenocarcinoma of the appendix that has invaded into adjacent organs such as the iliopsoas muscle.