case_images: PMC4317213_01
case_images: Clinical picture of a 3-year-old Rhodesian Ridgeback, which was presented with protrusion of the third eyelid. Upon inspection the enlargement of the nictitans and a temporodorsal deviation of the globe were present (A and B).
case_images: ccr30003-0050-f1.jpg
case_images: PMC4317213_01_ccr30003-0050-f1.jpg
case_images: fig01
case_images: Closer inspection revealed that the pigmented rim of the third eyelid was displaced ~0.5 cm away from the globe due to a mass, which was present in the entire visible bulbar aspect of the third eyelid (Fig.1).
case_images: The third eyelid and the mass appeared grossly to be completely removed by surgery (A) and was sent for histopathologic analysis (B and C).
case_images: ccr30003-0050-f2.jpg
case_images: PMC4317213_01_ccr30003-0050-f2.jpg
case_images: fig02
case_images: Following resection, grossly the mass seemed to be removed with clean margins (Fig.2).
case_images: Low power (A) and high power (B) photomicrographs of hematoxylin and eosin stained sections of the excised tumor within the nictitans. Arrows indicate mitotic figures. Bars: 200 mum (A) and 50 mum (B).
case_images: ccr30003-0050-f3.jpg
case_images: PMC4317213_01_ccr30003-0050-f3.jpg
case_images: fig03
case_images: Microscopic investigation revealed a mesenchymal, highly proliferative mass characterized by short interlacing streams, and bundles of closely packed spindle-shaped cells arranged in a storiform to herringbone pattern with few whorls (Fig.3).
case_images: Immunohistochemical staining of the tumor tissue. Virtually all cells were positive for vimentin (A) and up to 50% of the cells were positive for S-100 (B). Bars: 50 mum.
case_images: ccr30003-0050-f4.jpg
case_images: PMC4317213_01_ccr30003-0050-f4.jpg
case_images: fig04
case_images: The canthotomy wound was closed with a figure of eight suture (nylon 4/0, Ethilon ; Ethicon, Hamburg; Germany) and a temporary tarsorrhaphy was placed nasally (nylon 4/0 and two pieces of silicone tubing). Immunohistochemistry for vimentin, a marker staining intermediate filaments of mesodermal origin, found virtually in all the cells to be positive (Fig.4A). Additionally, up to 50% of the cells stained positive for S-100 (Fig.4B), indicating cells derived from the neural crest.