They are more often seen in the Caucasian Belnacasan (VX-765) population than in any other group [16]. Some studies suggest a difference in age at time of diagnosis depending on whether the tumor is localized or disseminated, and with higher age at time of diagnosis when disseminated compared to localized disease [2].There has been a disagreement whether GCCs have a preference regarding sex. Some studies found an increased frequency among women [12, 17], whereas others found no difference in prevalence between men and women [16, 18]. McCusker et al., who made a population-based study from the SEER database, 1973�C1998, which is also the largest study to date with 227 GCC patients, found no difference in prevalence according to sex with 52% male and 48% female [16].

Therefore the overall impression is that the distribution among gender is equal in GCC patients. 4. Clinical PresentationUp to 60% of the patients present with acute appendicitis where the GCC is discovered by coincidence in connection with surgery for acute appendicitis [17, 19]. Hence, contrary to classical appendix carcinoids, which are much more common and are often found as discrete tumors at the apex of the appendix, adenocarcinoids often show a diffuse thickening involving the total length of the appendix or alternatively only the base of the appendix [20]. This may induce occlusion of the lumen of the appendix, which is the cause of appendicitis [21]. In cases with disseminated disease, the primary symptom is often abdominal pain associated with an abdominal mass and weight loss.

However, only one study found a higher prevalence of abdominal pain combined with a palpable mass as primary symptom compared with symptoms of appendicitis [12]. In this study, by Tang et al., of 63 patients with GCC, most of the patients (63%) presented at an advanced clinical stage [12]. 5. DiagnosisThe majority of patients will have surgery for acute appendicitis and the diagnosis is revealed after pathological examination of the inflamed appendix. Here most of the GCCs show scattered positivity for chromogranin A and synaptophysin [4�C6, 12], and positivity for CK20 and CEA [4, 5]. This is in contrast to the classic appendix carcinoids where homogeneous staining for both chromogranin A and synaptophysin is most often seen. The proliferation index, Ki-67, which is of importance for the malignant potential in neuroendocrine tumors, has been studied thoroughly in a study by Tang et al.

They categorized GCC patients in 3 groups according to histology; group A, B, and C, respectively, and showed that the average Ki-67 index increases within the Carfilzomib groups, and that the survival rate is significantly reduced with increasing Ki67 index [12]. However, a recent study examined the role of Ki-67 in the prognosis of GCC [22].