A case of a horseshoe appendix.

Area of Science:

• Gastroenterology
• Surgical Anatomy
• Pathology

Background:

• Appendiceal anomalies are exceptionally rare, with horseshoe appendix being even rarer, with only five prior reported cases.
• A horseshoe appendix is characterized by dual communication with the colon and a single mesentery, with classification based on mesenteric arrangement and orifice location.

Purpose of the Study:

• To report a rare case of horseshoe appendix incidentally discovered during the investigation of a suspected ascending colon mass.
• To emphasize the clinical significance of considering rare anatomical anomalies, such as horseshoe appendix, in differential diagnoses.

Main Methods:

• Case presentation of a 78-year-old male with a positive fecal occult blood test.
• Diagnostic workup included colonoscopy and computed tomography (CT) scan, revealing a mass in the ascending colon connected to the appendix.
• Surgical intervention involved laparoscopic ileocecal resection, followed by macroscopic and microscopic pathological examination.

Main Results:

• The patient was diagnosed with ascending colon cancer pre-operatively, but post-operative findings revealed a horseshoe appendix and a type 1 tumor at the ascending colon orifice.
• Microscopic examination confirmed continuous mucosa and submucosa between the cecal and ascending colon orifices of the horseshoe appendix.
• The final diagnosis was tubulovillous adenoma associated with a horseshoe appendix.

Conclusions:

• Horseshoe appendix is a rare congenital anomaly that requires consideration in the diagnosis of gastrointestinal pathologies.
• This case underscores the importance of thorough pathological examination to identify rare anatomical variations, even when common pathologies are suspected.
• Awareness of such anomalies can aid in accurate diagnosis and appropriate surgical planning.