case_images: PMC5356292_01
case_images: 3D volume-rendered CT image of the ventral cervical region highlighting the vascular structures of the neck. The mass involving the right external jugular vein is clearly visible as well as the associated distention of the jugular vein and its S-configuration, proximal to the mass.
case_images: OpenVetJ-7-61-g001.jpg
case_images: PMC5356292_01_OpenVetJ-7-61-g001.jpg
case_images: F1
case_images: Computed tomography (CT) showed a 7.2 cm x 5.7 cm x 5.2 cm mass at the thoracic inlet in the right caudoventral neck area (Fig. 1). Mitotic figures ranged from 0-4 per high-power field (11 mitotic figures per 10 HPF), and there was moderate anisocytosis and anisokaryosis with kariomegaly and occasional bizarre cells.
case_images: The resected right external jugular vein has been opened longitudinally revealing the tunica intima (white arrow) and the leiomyosarcoma. The tumour has been turned over to show its pedunculated shape (white arrowhead) and the suture on the internal side of the jugular vein (black arrowheads) from the initial surgery.
case_images: OpenVetJ-7-61-g002.jpg
case_images: PMC5356292_01_OpenVetJ-7-61-g002.jpg
case_images: F2
case_images: The right external jugular vein was isolated, exposed with blunt dissection, and ligated (2.0 poliglyconate) cranial and caudal to the mass, which was then resected and submitted for histologic examination (Fig. 2). Mitotic figures ranged from 0-4 per high-power field (11 mitotic figures per 10 HPF), and there was moderate anisocytosis and anisokaryosis with kariomegaly and occasional bizarre cells.
case_images: The neoplasm was composed of spindle cells arranged in interlacing bundles and in a herringbone pattern. The cells have indistinct cell borders, a moderate amount of lightly eosinophilic cytoplasm, and oval or cigar-shaped nuclei. Several mitoses are evident (arrows) (H&E stain; bar = 100 microm).
case_images: OpenVetJ-7-61-g003.jpg
case_images: PMC5356292_01_OpenVetJ-7-61-g003.jpg
case_images: F3
case_images: The tumor was encapsulated and pedunculated, and histologic evaluation showed a neoplasm composed of spindle cells arranged in interlacing bundles with a herringbone pattern and no interstitial collagen matrix (Fig. 3). Mitotic figures ranged from 0-4 per high-power field (11 mitotic figures per 10 HPF), and there was moderate anisocytosis and anisokaryosis with kariomegaly and occasional bizarre cells.
case_images: Neoplastic cells showed moderate to strong alphaSMA immunelabeling. Small blood vessels within the tumour were strongly positive. Immunohistochemistry (IHC), diaminobenzidine, hematoxylin counterstain.
case_images: OpenVetJ-7-61-g004.jpg
case_images: PMC5356292_01_OpenVetJ-7-61-g004.jpg
case_images: F4
case_images: Mitotic figures ranged from 0-4 per high-power field (11 mitotic figures per 10 HPF), and there was moderate anisocytosis and anisokaryosis with kariomegaly and occasional bizarre cells. Immunohistochemical staining with vimentin, desmin, and alphaSMA antibodies was positive in all sections (Fig. 4).