title: A case of a horseshoe appendix.
abstract: Anomalies of the appendix are extremely rare, and a horseshoe appendix is even rarer. A literature search has revealed only five reported cases. In this report, we present a case of a horseshoe appendix.A 78-year-old man was referred for further examination following a positive fecal occult blood test. A mass in his ascending colon was detected on colonoscopy, while computed tomography showed that it was connected to the appendix. Tumor invasion derived from the ascending colon or appendix was suspected. We diagnosed ascending colon cancer prior to laparoscopic ileocecal resection. Macroscopic findings showed that the appendix connected to the back side of the mass, while microscopic findings showed that the mucosa and submucosa were continuous from the appendiceal orifice in the cecum to the other orifice in the ascending colon, where a type 1 tumor was observed on the orifice. We eventually diagnosed the patient with tubulovillous adenoma and a horseshoe appendix.A horseshoe appendix communicates with the colon at both ends and is supplied by a single fan-shaped mesentery. Cases are classified by the disposal of the mesentery and the location of the orifice. Anatomical anomalies should be considered despite the rarity of horseshoe appendices.
authors.affiliation: Department of Surgery, Japanese Red Cross Kyoto Daiichi Hospital, 15-749 Honmachi, Higashiyama, Kyoto, Kyoto, Japan. kazuya-takabatake@kyoto1-jrc.org.
authors.forename: Kazuya
authors.identifier: http://orcid.org/0000-0002-8847-7860
authors.initials: K
authors.lastname: Takabatake
authors.affiliation: Department of Surgery, Japanese Red Cross Kyoto Daiichi Hospital, 15-749 Honmachi, Higashiyama, Kyoto, Kyoto, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Ikeda
authors.affiliation: Department of Surgery, Japanese Red Cross Kyoto Daiichi Hospital, 15-749 Honmachi, Higashiyama, Kyoto, Kyoto, Japan.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Furuke
authors.affiliation: Department of Surgery, Japanese Red Cross Kyoto Daiichi Hospital, 15-749 Honmachi, Higashiyama, Kyoto, Kyoto, Japan.
authors.forename: Chikage
authors.initials: C
authors.lastname: Kato
authors.affiliation: Department of Surgery, Japanese Red Cross Kyoto Daiichi Hospital, 15-749 Honmachi, Higashiyama, Kyoto, Kyoto, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Kishimoto
authors.affiliation: Department of Surgery, Japanese Red Cross Kyoto Daiichi Hospital, 15-749 Honmachi, Higashiyama, Kyoto, Kyoto, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Kumano
authors.affiliation: Department of Surgery, Japanese Red Cross Kyoto Daiichi Hospital, 15-749 Honmachi, Higashiyama, Kyoto, Kyoto, Japan.
authors.forename: Kenichiro
authors.initials: K
authors.lastname: Imura
authors.affiliation: Department of Surgery, Japanese Red Cross Kyoto Daiichi Hospital, 15-749 Honmachi, Higashiyama, Kyoto, Kyoto, Japan.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Shimomura
authors.affiliation: Department of Surgery, Japanese Red Cross Kyoto Daiichi Hospital, 15-749 Honmachi, Higashiyama, Kyoto, Kyoto, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kubota
authors.affiliation: Department of Surgery, Japanese Red Cross Kyoto Daiichi Hospital, 15-749 Honmachi, Higashiyama, Kyoto, Kyoto, Japan.
authors.forename: Fumihiro
authors.initials: F
authors.lastname: Taniguchi
authors.affiliation: Department of Surgery, Japanese Red Cross Kyoto Daiichi Hospital, 15-749 Honmachi, Higashiyama, Kyoto, Kyoto, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Shioaki
keywords: Anomalies of the appendix; Horseshoe appendix