One type of duplex appendix: horseshoe appendix

Figures & data

Figure 1 Abdominal CT showing the gas-liquid levels and dilatation of the intestinal tract and an obscured appendiceal area revealing edema of this area (circle).

Note: However, when we reviewed the CT repeatedly after the operation, the images appeared to show that the appendix was shaped like a horseshoe, a finding that was easily ignored.
Abbreviation: CT, computed tomography.

Figure 2 The horseshoe appendix was bundled and cut into two parts (arrow) to manage it side by side for severe adhesions in the appendiceal area.

Figure 3 Both divided bases (arrow) are completely shown.

Figure 4 Frontally displaced mesentery (our case is of this type).

Figure 5 Sagittally displaced mesentery.

Table 1 Cases of a horseshoe appendix

Author	Year	Age (years)	Sex	Diagnosis	Length	Type	Internal hernia	Other anomalies	Orifice	Operation
Mesko et al^Citation12	1989	33	Male	Appendicitis	Unclear	Unclear	Unclear	Unclear	Unclear	Appendectomy
Dong et al^Citation19	1994	46	Male	Bowel occlusion	20 cm	Frontal	Yes/ileum	Unclear	Cecum-cecum	Appendectomy + enterotomy
Dasgupta et al^Citation10	1999	48	Male	Appendicular mass	Unclear	Frontal	No	Unclear	Cecum-cecum	Appendectomy
Li and Yu^Citation20	2000	30	Female	Appendicitis	Unclear	Frontal	No	Unclear	Cecum-cecum	Appendectomy
Cai and Lin^Citation21	2006	56	Male	Appendicitis	8 cm	Sagittal	No	Unclear	Cecum-cecum	Appendectomy
Calotă et al^Citation4	2010	43	Female	Bowel occlusion	13.5 cm	Sagittal	No	Unclear	Cecum-cecum	Appendectomy
Ninos et al^Citation11	2010	20	Female	B-cell non-Hodgkin’s lymphoma	4 cm	Sagittal	No	Unclear	Cecum-cecum	Appendectomy + chemical therapy
Dube et al^Citation6	2011	32	Male	Appendicitis	7 cm	Sagittal	No	Unclear	Cecum-hepatic flexure of the colon	Appendectomy
Li and Liu^Citation22	2012	46	Male	Appendicitis + bowel occlusion	7 cm	Unclear	Yes/ileum	Unclear	Cecum-cecum	Appendectomy + enterotomy
Oruç et al^Citation9	2013	64	Female	Appendicitis	Unclear	Unclear	No	Unclear	Cecum-cecum	Appendectomy
Bulut et al^Citation13	2016	52	Female	Appendicitis	8 cm	Frontal	No	Unclear	Cecum-cecum	Appendectomy
Singh et al^Citation8	2016	5	Male	Appendicitis	Unclear	Frontal	No	None	Cecum-cecum	Appendectomy
Takabatake et al^Citation5	2016	78	Male	Tubulovillous adenoma in ascending colon	Unclear	Sagittal	No	Unclear	Cecum-ascending colon	Ileocecal resection
Our case	2017	22	Male	Appendicular mass	15 cm	Frontal	No	Unclear	Cecum-cecum	Appendectomy

Table 2 Classification of appendiceal anomalies

• Number anomalies

1. Agenesis: absence of appendix

2. Duplex appendix

A: partial duplication with both appendices sharing a common base like “Y-shaped” on a single cecum

B: complete duplication of the appendix on a single cecum

• B1 avian type or “bird-like appendix”: two appendices symmetrically placed on either side of the ileocecal valve. In humans, it is found associatedwith intestinal and/or genitourinary anomalies

• B2 tenia coli cecum type: one appendix arising from the usual site of the cecum and the other arising from the cecum along the tenia

• B3 tenia coli hepatic flexure type: one appendix arising from the usual site of the cecum and the other arising from the hepatic flexure of thecolon along the tenia

• B4 tenia coli splenic flexure type: one appendix arising from the usual site of the cecum and the other arising from the splenic flexure of thecolon along the tenia

The later three (B2, B3, and B4) are not associated with other embryonic anomalies generally

C: duplication of the cecum, each has its own appendix

3. Triplex appendix: complete triplication of appendix on the cecum

• Shape anomalies

Horseshoe appendix

Location of the mesentery

• Sagittal disposal: the both bases of the appendix are along the tenia in sagittal direction

Location of the orifice

• Cecum-cecum

• Cecum-ascending colon

• Cecum-hepatic flexure of the colon

• Frontal disposal: the bases of the appendix are not on the tenia (Figure 5)

Location of the orifice

• Cecum-cecum

Note: Data from these studies.^2–5,14,15

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