case_images: PMC10944911_01
case_images: Radiological imaging, histopathological features and immunohistochemical staining of coexistence of low-grade appendiceal mucinous neoplasia (LAMN) and goblet cell adenocarcinoma (GCA) in the appendix. (A). Abdominal CT revealed a large cystic mass in the appendix (arrow), indicating a cystic appendiceal tumor. (B). Gross examination demonstrated a dilated cystic mass (arrows) with accumulation of mucin in the appendix and a nodule (red triangles) in the cystic wall. (C). Low-power field showed a dilated appendix with intramural epithelium pushing invasion in the thickened wall. In addition, lymphoid tissue was markedly absent. (H&E, magnification x10). (D). Histopathological diagnosis of the lesion was consistent with LAMN and GCA. The tumor cells of LAMN and GCA were adjacent. (H&E, magnification x100). (E). LAMN showed low-grade, slightly elongated nuclei and abundant mucin-filled cytoplasm. (H&E, magnification x400). (F). The grade 1 GCA consisted of clusters of cuboidal cells and goblet-like mucinous cells in discrete, clustered units embedded in dense collagen. (H&E, magnification x400). Immunohistochemical staining revealed positive expression of CK20, CDX2 and Villin in the tumor cells of both LAMN and GCA. Focal positivity for Synaptophysin (Syn) and chromogranin (CgA) was observed in GCA tumor cells, while LAMN tumor cells showed negative staining for these markers. The Ki67 index was approximately 5% and 3% in the tumor cells of LAMN and GCA, respectively. (Magnification x200).
case_images: fonc-14-1313548-g001.jpg
case_images: PMC10944911_01_fonc-14-1313548-g001.jpg
case_images: f1
case_images: Subsequently, the patient was admitted to our hospital where a new abdominal CT was ordered, revealing a large dilated thickened cystic mass in the appendix measuring 5.9 cm x 4.9 cm ( Figure 1A ). On gross examination ( Figure 1B ), the cystic mass measured 60mm x 50mm was located in the appendix, and the appendix wall was thickened by approximately 1mm to 12mm. The lymphoid tissue of the appendix was reduced or absent ( Figure 1C ). There were two distinct and adjacent histological components ( Figure 1D ). The mucinous epithelial proliferated cells replaced the normal epithelial mucosa, and tumors exhibited columnar cytoplasmic mucin vacuoles, which compressed the nucleus ( Figure 1E ). Microscopic examination at high magnification showed that the tumors were goblet-like mucinous cells with tumor cell clusters ( Figure 1F ). Immunohistochemical staining results are shown in  Figure 1 .