Appendiceal tumors represent a subset of colonic neoplasms that frequently defy early diagnosis only to present at advanced stage with peritoneal metastasis. Data on early detection by colonoscopy is limited to case reports or series. The aim of this study is to determine the diagnostic yield of colonoscopy in detecting appendiceal lesions in patients with appendiceal adenocarcinoma and pseudomyxoma peritonei.

We reviewed clinicopathologic data on 121 consecutive patients with histologically confirmed appendiceal adenocarcinoma with pseudomyxoma peritonei presenting to our institution for intraperitoneal hyperthermic chemotherapy (IPHC) and cytoreductive surgery between February, 1993 and August, 2007, focusing on the colonoscopy findings.

Preoperative colonoscopic data were available on 64 patients (average age = 51; 52 for IPHC patients). Abnormal findings included seven patients with appendiceal lesions (11%), 12 patients with cecal abnormalities (19%), and 28 patients with polyps (44%). Twenty-three patients (36%) had a normal colonoscopy. Malignancy was documented in two of the 64 (3.1%) patients on preoperative colonoscopy biopsies.

Appendiceal abnormalities are infrequently seen on colonoscopy and rarely yield a diagnostic biopsy in patients with appendiceal carcinoma. We found that nearly 42% of patients with carcinoma of the appendix have synchronous colonic polyps, a much higher prevalence than would be expected, supporting a role for a perioperative colonoscopy.

Appendiceal mucoceles are uncommon cystic neoplasms characterized by distension of the appendiceal lumen with mucus. There have been no reported series of colonoscopically diagnosed mucoceles with clinicopathologic correlation.

A retrospective review of colonoscopies performed at our institution over the past 14 years was undertaken with patient demographics, clinical data, surgical outcomes, and histopathology obtained from hospital records.

Seven patients (6 women) with mucocele of the appendix were identified at colonoscopy. Three had complained of right lower quadrant pain. All 7 patients underwent surgical resection. Histopathology demonstrated mucinous cystadenoma in all. No cases revealed carcinoma, and there have been no deaths related to the mucocele.

Appendiceal mucoceles may be recognized at colonoscopy as a smooth bulbous submucosal lesion of the cecum with an impression formed by the appendiceal orifice. Recognition at colonoscopy is important because it enables accurate diagnosis and directs management. Surgery is recommended in all cases given the risk of malignancy or perforation with resultant pseudomyxoma peritonei.

The authors report the case of a 60-year-old male patient. In November 2001 he developed intestinal symptoms of bloody diarrhea and abdominal pain. Colononoscopy and biopsy established the diagnosis of ulcerative colitis (proctosigmoiditis). The disease activity was moderate at the beginning. No significant laboratory alterations were found (including CEA, CA19-9), and mesalazine was started orally. He was in remission until November 2003, when he was admitted to our Outpatient Clinic for upper and right lower abdominal pain and bloody diarrhea. Colonoscopy found proctosigmoiditis with a moderate activity, gastroscopy revealed chronic gastritis, laboratory data was normal. Treatment was amended with mesalazine clysma and methylprednisolone (16 mg) orally. Symptoms ameliorated; however, right lower abdominal pain persisted. US and CT examination demonstrated a pericecal cystic mass (11 cm x 3.5 cm). At first pericecal abscess was suspected, as the previous US examination (6 mo earlier) had revealed normal findings. Fine needle aspiration was performed. Cytology confirmed the diagnosis of mucocele. The patient underwent partial cecum resection and extirpation of the mucocele. He recovered well and the final histology revealed a cystadenoma of the appendix. Follow up was started. The patient is now free of symptoms. Although primary adenocarcinoma of the appendix is uncommon, the authors emphasize that preoperative diagnosis of an underlying malignancy in a mucocele is important for patient management; however, it is difficult on imaging studies.