case_images: PMC10730246_01
case_images: PMC10730246_02
case_images: A yellow-brown, friable intraluminal polypoid mass in the gallbladder.
case_images: CRIPA2023-4847053.001.jpg
case_images: PMC10730246_02_CRIPA2023-4847053.001.jpg
case_images: fig1
case_images: Macroscopic examination of the gallbladder revealed a 3.9 x 2.5 x 2.0 cm yellow-brown, friable intraluminal polypoid mass in the gallbladder (Figure 1).
case_images: Histological appearance of melanoma of gallbladder. (a) The intraluminal tumor was predominantly arising from the mucosa of the gallbladder (HE x 20). (b) The tumor is composed of polygonal cells arranged in a perivascular pattern with abundant eosinophilic cytoplasm, vesicular nuclei, and prominent eosinophilic nucleoli. (c) Dense melanin pigments were found within the cytoplasm of the neoplastic cells (HE x 200). (d) Junctional activity was present (HE x 200).
case_images: CRIPA2023-4847053.002.jpg
case_images: PMC10730246_02_CRIPA2023-4847053.002.jpg
case_images: fig2
case_images: Histopathologic examination of the gallbladder tumor showed that the intraluminal tumor was predominantly arising from the mucosa of the gallbladder (Figure 2(a)). The tumor was composed of nests of large atypical epithelioid cells arranged in a perivascular pattern with abundant eosinophilic cytoplasm, pleomorphic vesicular nuclei, and prominent nucleoli in a background of acute and chronic inflammation (Figure 2(b)). Additionally, the tumor cell cytoplasm contained abundant granular brown pigment (Figure 2(c)). Junctional activity was identified, featuring aggregates of malignant melanoma cells at the junction of epithelium and lamina propria (Figure 2(d)).
case_images: Neoplastic cells were immunostained with anti-S-100 (a), HMB-45 (b), and MART-1 (c) antibodies. x200.
case_images: CRIPA2023-4847053.003.jpg
case_images: PMC10730246_02_CRIPA2023-4847053.003.jpg
case_images: fig3
case_images: MART-1 (Figure 3(c)). Molecular analysis revealed the absence of KIT mutations, NRAS mutations, or the BRAF codon 600 mutation in the tumor.