An 81-year-old Caucasian woman was admitted with a two week history of increasing shortness of breath and dizziness. Although frail she was otherwise medically fit, a non-smoker and had no significant family history. She had a history of endometrial cancer, treated 14 years previously with hysterectomy, bilateral salpingo-oopherectomy and adjuvant radiotherapy. The onset of her symptoms was gradual and comprised malaise, shortness of breath initially on exertion and more lately at rest and dizziness especially on standing up from sitting. She denied any symptoms related to her gastrointestinal tract such as haematemesis, melaena, change in bowel habit or abdominal pain. On examination she appeared pale and was dyspnoeic, tachycardic and normotensive. Examination of the abdomen revealed it to be soft and non-tender, with no palpable abdominal masses. Blood tests showed a microcytic, normochromic anaemia with a haemoglobin of 3.8 gm/dL and a carcinoembryonic antigen level of 15 ng/ml. Blood biochemistry was within normal limits. After blood transfusion sources of intestinal haemorrhage were sought; an upper gastrointestinal endoscopy was unremarkable and colonoscopy was unhelpful because a fixed rectum, secondary to previous surgery and radiotherapy for endometrial cancer impeded the progress of the scope. An air contrast barium enema examination was performed and this showed an indentation of the caecal wall (Figure 1a) suggestive of a caecal tumour. A computerized tomography scan demonstrated thickening of the caecal pole and a mucocele of the appendix (Figure 1b) suggesting a caecal tumour that causing obstruction of the appendiceal orifice. There was no sign of extracolonic or metastatic disease. After counselling the patient and her family, it was decided the best treatment option was to perform a laparoscopically assisted right hemicolectomy. At laparoscopy, the diagnosis of a mucolcele of appendix was confirmed. The appendiceal mucocele was perforated and surrounded by mucinous deposits. The caecum appeared bulky and abnormal. A laparoscopic assisted right hemicolectomy and partial omentectomy were performed without complication. Postoperatively the patient developed hyponatraemia and a paralytic ileus, delaying her recovery. She was discharged eight days after the surgery and followed up in the outpatients two weeks later when she reported feeling well recovered from the surgery.
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.