A horseshoe appendix is an extremely rare variant of the vermiform appendix, in which the appendix arises from the cecum and curves back on itself to re-insert into the cecum, similar to a semicircular canal in the inner ear.
Anatomic variation of the appendix is extremely rare. In a study of 50,000 appendix surgical specimens by Donald C Collins, an American general surgeon and pathologist, appendiceal agenesis was only seen in four cases, and duplication was seen in two cases, a prevalence of 0.004%. But no cases of horseshoe appendix were seen 1. In total eleven cases of horseshoe appendix have been reported in the English medical literature with a further four in the Chinese literature 1-9.
The appendix forms a loop with two appendiceal orifices and in theory at least acute appendicitis should be less likely as it is no longer a blind-ending tube, although at least one case has been described 2.
History and etymology
The first case was described as recently as 1989 by Thomas W Mesko, an American surgeon, and colleagues 1.
- 1. Mesko TW, Lugo R, Breitholtz T. Horseshoe anomaly of the appendix: a previously undescribed entity. (1989) Surgery. 106 (3): 563-6. Pubmed
- 2. DasGupta R, Reber PU, Patel AG. Horseshoe appendicitis. (1999) The European journal of surgery = Acta chirurgica. 165 (11): 1095-6. doi:10.1080/110241599750007973 - Pubmed
- 3. Calotă F, Vasile I, Mogoantă S, Zavoi R, Paşalega M, Moraru E, Stoicea C. Horseshoe appendix: a extremely rare anomaly. (2010) Chirurgia (Bucharest, Romania : 1990). 105 (2): 271-4. Pubmed
- 4. Oruç C, Işık O, Ureyen O, Kahyaoğlu OS, Köseoğlu A. An extremely rare appendiceal anomaly: horseshoe appendicitis. (2013) Ulusal travma ve acil cerrahi dergisi = Turkish journal of trauma & emergency surgery : TJTES. 19 (4): 385-6. doi:10.5505/tjtes.2013.67424 - Pubmed
- 5. Singh ChG, Nyuwi KT, Rangaswamy R, Ezung YS, Singh HM. Horseshoe Appendix: An Extremely Rare Appendiceal Anomaly. (2016) Journal of clinical and diagnostic research : JCDR. 10 (3): PD25-6. doi:10.7860/JCDR/2016/16569.7494 - Pubmed
- 6. Takabatake K, Ikeda J, Furuke H, Kato C, Kishimoto T, Kumano T, Imura K, Shimomura K, Kubota T, Taniguchi F, Shioaki Y. A case of a horseshoe appendix. (2016) Surgical case reports. 2 (1): 140. doi:10.1186/s40792-016-0261-3 - Pubmed
- 7. Liu J, Dong C, Wang H, Sun D, Liang R, Gao Z, Wang L. One type of duplex appendix: horseshoe appendix. (2018) Therapeutics and clinical risk management. 14: 1987-1992. doi:10.2147/TCRM.S179929 - Pubmed
- 8. Choi SJ, Chae G, Park SB, Hong SK, Kim YH, Moon SB, Kim SY, Kim H. Horseshoe appendix identified during laparoscopic appendectomy: A case report and literature review. (2019) Medicine. 98 (5): e14104. doi:10.1097/MD.0000000000014104 - Pubmed
- 9. A. Ninos, G. Douridas, E. Papakonstantinou, M. Vidali, G. Liapi, S. Maletsikopoulos, P. Antonakas, L. Palivos, J. Papandrikos, C. Farazi, S. Pierrakakis. A horseshoe double appendix positioned on a non-Hodgkin lymphoma. (2010) Hellenic Journal of Surgery. 82 (1): 73. doi:10.1007/s13126-010-0003-0