case_images: PMC11251538_01
case_images: Ocular conjunctival mass with hemorrhage in a 16-year-old male mixed-breed dog.
case_images: vrf-15-257-g001.jpg
case_images: PMC11251538_01_vrf-15-257-g001.jpg
case_images: F1
case_images: A 16-year-old male mixed-breed dog was brought to an animal clinic because of a mass with hemorrhage at the right conjunctiva (Fig. 1).
case_images: Histopathological examination of ocular conjunctival mass using H & E staining. A) The mass was composed of polygonal or oval tumor cells arranged in diffuse pattern. Extensive necrosis (arrow) and hemorrhage (arrowhead) were observed in the intra-tumor tissue (bar = 100 mum); B) Polygonal or round tumor cells with distinct nucleoli and abundant eosinophilic cytoplasm. Mitoses were frequently observed which are indicated by arrows (bar = 20.00 mum); C) Arrows show part of the cord-like and papillary epithelioid cells in the intra-tumor tissue (bar = 20.00 mum).
case_images: vrf-15-257-g002.jpg
case_images: PMC11251538_01_vrf-15-257-g002.jpg
case_images: F2
case_images: Microscopically, the mass comprised polygonal or round tumor cells with distinct cell borders arranged in a nested and diffuse pattern (Fig. 2A). The tumor cells had round-to-oval fine hyperchromatic nuclei containing distinct multiple nucleoli and abundant eosinophilic or pale cytoplasm (Fig. 2B). Extensive necrosis, hemorrhage and part of the cord-like and papillary epithelioid cells were observed in the intra-tumor tissue (Fig. 2C).
case_images: Immunohistochemical (IHC) analyses of ocular conjunctival mass. A) The tumor cells were positive for vimentin (bar = 20.00 mum); B) The tumor cells were positive for a-smooth muscle actin (bar = 20.00 mum); C) The tumor cells were negative for Melan-A (bar = 20.00 mum); D) The cord-like and papillary epitheloid cells were positive for neuron-specific enolase shown by arrows (bar = 20.00 mum).
case_images: vrf-15-257-g003.jpg
case_images: PMC11251538_01_vrf-15-257-g003.jpg
case_images: F3
case_images: Immunohistochemically, the tumor cells were positive for vimentin (Fig. 3A) and SMA (Fig. 3B), and negative for CK AE1/AE3 and CAM5.2, carcinoembryonic antigen, p63, PNL2, Melan-A (Fig. 3C), synaptophysin, S100, GFAP, NSE, neurofilament, desmin, Iba-1, HLA-DR, CD163, c-kit and factor VIII-related antigen. Also, laminin-positive basement membrane was not observed. On the other hand, the cord-like and papillary epithelioid cells were positive for vimentin, S100 and NSE (Fig. 3D).