title: Transformation of low-grade mucinous neoplasm of the appendix with pseudomyxoma peritonei to high-grade sarcomatoid carcinoma.
abstract: A 66-year-old man initially underwent appendectomy and cytoreductive surgery for a low-grade appendiceal mucinous neoplasm with pseudomyxoma peritonei. One and a half years later, multiple disseminated lesions developed in rectus abdominis muscle and peritoneal cavity. Biopsy showed histopathological transformation to sarcomatoid carcinoma. This case illustrates that evolution of low-grade pseudomyxoma peritonei to high-grade carcinoma truly develops in some patients. The development of this dedifferentiation appears associated with aggressive behavior and poor clinical outcome.
authors.affiliation: Department of Surgery, MacKay Memorial Hospital and Mackay Medical College, Taipei, Taiwan.
authors.forename: Yu-Nung
authors.initials: YN
authors.lastname: Chen
authors.affiliation: Department of Surgery, MacKay Memorial Hospital and Mackay Medical College, Taipei, Taiwan ; Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan.
authors.forename: Jie-Jen
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Department of Surgery, MacKay Memorial Hospital and Mackay Medical College, Taipei, Taiwan.
authors.forename: Shih-Ping
authors.initials: SP
authors.lastname: Cheng
authors.affiliation: Department of Surgery, MacKay Memorial Hospital and Mackay Medical College, Taipei, Taiwan ; Mackay Junior College of Medicine, Nursing, and Management, Taipei, Taiwan.
authors.forename: Chung-Hsin
authors.initials: CH
authors.lastname: Tsai
keywords: Dedifferentiation; Pseudomyxoma peritonei; Recurrence