ABSTRACT
Villous adenomas of the appendix are rare and usually diagnosed incidentally after appendectomy due to acute appendicitis. Appendicular villous adenomas have potential risk for progression to invasive carcinoma, just as other adenomas located in colon and rectum. Appendectomy can be considered sufficient treatment if the tumor measures less than 2 cm, there is no mesoappendicular or nodal spread, and the resection margins are healthy. We present a patient diagnosed with villous adenoma with high-grade dysplasia detected in histopathological examination of appendectomy specimen.
Introduction
Adenomas of the appendix account for approximately 0.02-0.14% of appendiceal lesions.1 They are usually seen in individuals 60-80 years of age. Although most appendiceal adenomas are detected incidentally in appendectomy specimens, cases associated with intussusception, appendiceal perforation, and rectal hemorrhage have also been described in case reports.2,3 Here, we present a case of villous adenoma with high-grade dysplasia detected in histopathological examination following appendectomy due to acute appendicitis.
Discussion
Adenomas of the appendix account for approximately 0.02-0.14% of appendiceal lesions.1 They usually manifest clinically as acute appendicitis and most are diagnosed during histopathological examination of the appendectomy specimen. In addition, several cases of intussusception, appendiceal perforation, rectal hemorrhage, or incidental detection during colonoscopy have also been reported.2,3 Colon and appendiceal adenomas are dysplastic polypoid lesions and are divided into three groups: tubular, villous, and tubulovillous. The potential for malignant conversion is associated with tumor size (<5% for those smaller than 1 cm; >50% for those larger than 2 cm) and pathological type (5% for tubular adenoma, 20% for tubulovillous adenoma, and 40% for villous adenoma).4,5 Villous adenomas usually develop in the rectum and sigmoid colon.6 The incidence of primary appendiceal villous adenoma was determined as approximately 0.006% in appendectomy series.3 Only 71 cases of villous adenoma have been reported in the literature.7 Appendiceal villous adenomas pose a risk of progression to invasive carcinomas such as other villous adenomas of the large bowel.2 Appendectomy is sufficient when the tumor is less than 2 cm in size, mesoappendiceal and lymph node involvement is absent, and a clean surgical margin is achieved. Right hemicolectomy and lymph node dissection are recommended in cases with tumors larger than 2 cm, mesoappendiceal invasion, lymph node involvement, positive surgical margin, and lymphatic or vascular embolism.8 The follow-up approach for appendiceal adenomas is similar to those of the colon and rectum.9 Due to the relationship between adenomas of the appendix and colon adenocarcinoma, colonoscopy is recommended for patients with incidentally detected appendiceal tumors.10
