The inverted appendix - a potentially problematic diagnosis: clinicopathologic analysis of 21 cases

Area of Science:

• Gastroenterology
• Pathology
• Surgical Oncology

Background:

• Inverted appendices are uncommon but can be mistaken for other lesions during endoscopic procedures.
• Diagnostic confusion can arise between endoscopists and pathologists when encountering inverted appendices.

Purpose of the Study:

• To describe the clinicopathological features of inverted appendices over a 30-year period.
• To aid in the accurate identification and diagnosis of inverted appendices.

Main Methods:

• Retrospective review of 21 identified inverted appendix cases.
• Analysis of clinical presentation, endoscopic findings, and pathological characteristics.
• Correlation of histological features with associated pathological processes.

Main Results:

• Predominantly affected middle-aged women, often detected incidentally during colonoscopy.
• Endoscopic appearance was polypoid in the proximal cecum; 5 cases mischaracterized as cecal polyps.
• Associated pathologies included endometriosis, mucocoele, neoplasia, and inflammatory fibroid polyp.
• Histological hallmarks included a dome-like mucosal surface, muscularis propria with ganglion cells, and lymphoid aggregates.

Conclusions:

• Consider inverted appendix in cecal polypectomy specimens with specific histological features (dome-like surface, muscularis propria, lymphoid aggregates).
• Prompt recognition on Hematoxylin and Eosin (H&E) staining prevents diagnostic delays and resource misallocation.
• No perforation-associated morbidity observed in post-polypectomy patients with follow-up.