Incidentally Discovered Adenocarcinoma in situ of the Appendix in a Young Woman.

Primary appendiceal adenocarcinoma is an infrequent disease. This report presents a rare case of incidentally discovered carcinoma in situ of the appendix. A 35-year-old parturient female simultaneously underwent appendectomy and oophorectomy due to an ovarian abscess that adhered to the appendix during cesarean section. Although her excised appendix showed no apparent tumorous lesion, histopathological examination revealed carcinoma in situ in the excised appendix. She underwent additional right hemicolectomy a few days later due to the possibility of a positive surgical margin. Histopathological examination detected no malignant cells in the resected specimen. She was discharged without any complications and has since remained healthy. Appendiceal adenocarcinoma is generally considered to be difficult to diagnose during the early stage because it seldom shows any specific findings. This results in a poor prognosis. Histopathological examination is not always conducted for appendices resected during other surgery. However, the current study suggests that a careful routine histopathological examination of excised appendix, as well as careful preoperative examination and detailed intraperitoneal inspection during surgery, is indeed important to detect occult appendiceal tumors.