Incidental cystadenocarcinoma of the appendix in a patient undergoing laparoscopic right hemicolectomy for caecal cancer: a case report
© licensee BioMed Central Ltd. 2009
Received: 27 October 2008
Accepted: 18 April 2009
Published: 9 June 2009
Primary appendiceal neoplasms are rare and usually found incidentally after appendicectomy for suspected appendicitis. We report a case of a perforated cystadenocarcinoma of the appendix occurring synchronously with caecal adenocarcinoma in an 81-year-old woman without abdominal symptoms or signs, who presented with iron deficiency anaemia.
Primary appendiceal neoplasms are uncommon  and usually found incidentally after appendicectomy for suspected appendicitis . Preoperative diagnosis is frequently difficult. Whilst the symptoms are typically non-specific, imaging studies are not usually diagnostic . Here, we report a case of cystadenocarcinoma of the appendix presenting asymptomatically and occurring synchronously with caecal adenocarcinoma. This rare but important incidental finding in a patient without any abdominal signs or symptoms is significant for the management and prognosis of the patient. A laparoscopic approach allowed excellent assessment of the disease and its extent without compromising oncological principles or further therapeutic intervention that may be required.
Histology of the resected specimen demonstrated a T3N1M0 adenocarcinoma of the caecum with 2 out of 14 lymph nodes containing tumour cells. Surprisingly a mucinous neoplasm of the appendix was also identified, separated from the caecal tumour by a segment of normal caecal mucosa. Each tumour had a distinct morphology. The cytological characteristics of the caecal tumour were typical of a moderately differentiated colonic adenocarcinoma (Figure 1d), whist the appendiceal tumour had a striking viliform structure with abundant basal nuclei and mucin extruding through and onto the serosal surface (Figure 1e). Neoplastic cells were not seen on the appendix serosa or within the mucinous deposits. Immunohistochemistry using an antibody against p53 (not shown) demonstrated over expression of the abnormal protein in the caecal lesion, whereas the appendiceal tumour was devoid of positive staining. There were also differences in cell proliferation rates in the two tumours, as demonstrated by immunostaining with Ki67 (not shown), which was strongly positive in the caecal carcinoma but weak in the appendiceal lesion. No abnormal cells or mucin were detected in the resected omentum.
Neoplasia of the appendix, although rare, is an important diagnosis to consider in patients with a mucocele of the appendix. The clinical presentation of tumours of the appendix can be similar to acute appendicitis and frequently the diagnosis is made incidentally . The frequency of appendix specimens removed for suspected appendicitis that contain a neoplasm is 0.08% . The diagnosis of cystadenocarcinoma of the appendix in this case was surprising as we had assumed that the mucocele was secondary to obliteration of the appendiceal orifice by caecal cancer. Pre-operative diagnosis is often challenging and infrequent but when a mucocele of the appendix is identified, a primary appendiceal tumour should be considered. CT imaging typically identifies a cystic nodular mass with an enhancing wall in the right iliac fossa . Perforation of the mucocele resulting in dissemination of tumour cells can occur and examination of the peritoneal cavity in our patient revealed mucinous deposits adjacent to the perforated appendix. Interestingly, when a patient presents with a cystadenocarcinoma of the appendix a second gastrointestinal tumour is present in 20-40% of cases . The synchronous caecal tumour in our patient necessitated full resection of the right hemicolon and its mesentery, which was performed laparoscopically and with adherence to oncological principles. Evidence supporting a laparoscopic approach to treatment for cystadenocarcinoma of the appendix is limited to a few reports, although resection of other primary appendiceal tumours has been safely effected using laparoscopic surgery . In our experience, performing the resection laparoscopically did not compromise oncological safety and in fact we were afforded excellent views of the whole peritoneal cavity allowing assessment of disease extent and good access to remove all visible mucinous deposits.
Cystadenocarcinoma of the appendix is an important diagnosis to consider in patients diagnosed with a mucocele of the appendix. Although the these tumours usually present clinically like acute appendicitis, this case was interesting because the mucocele remained completely asymptomatic despite perforation and the patient presented with systemic symptoms related to a second colonic neoplasm.
Written informed consent was obtained from the patient for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
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