Combined goblet cell carcinoid and mucinous cystadenoma of the vermiform appendix

Figure 1 Histopathological examination. A: Mucinous cystadenoma of the appendix combined with infiltrating goblet cell carcinoid (HE, × 50); B: The mucinous cystadenoma of the appendix showing lumen lined by mucous-containing bland epithelial cells (HE, × 100); C: Cells with neuroendocrine cytonuclear features in goblet cell carcinoid (HE, × 200); D: Mucin-filled neoplastic cells of goblet cell carcinoid (HE, × 200); E: The infiltrating nests of goblet cell carcinoid appear to arise from the basiglandular region of the intestinal crypts in close proximity to the mucinous cystadenoma (HE, × 100).

Figure 2 Immunohistochemically. The neoplastic cells of the goblet cell carcinoid expressed strong and diffuse positivity for cytokeratin 20 (× 100).