History
A 6.5-year-old 8.5-kg (18.7-lb) neutered male domestic shorthair cat was submitted for necropsy after development of acute dyspnea and its subsequent death.
Clinical and Gross Findings
The cat died en route to the veterinary clinic, and no physical examination was conducted. The carcass was submitted for necropsy. Gross examination revealed a good body condition with adequate body fat stores. The abdominal cavity contained 400 mL of unclotted blood. The mesentery and intestinal serosa at the ileocecocolic junction were dark red. The cecum was transmurally thickened and had blood clots attached to the serosa (Figure 1). In these areas, the intestinal mucosa was diffusely red and covered by dark red, semipasty contents. The liver was diffusely tan and had a prominent lobular pattern. No other gross changes were observed.
Photograph of the ileocecocolic junction of a 6.5-year-old cat that died after an episode of acute dyspnea. The serosa of the distal portion of the ileum, the entire cecum, and the proximal portion of the colon is diffusely dark red to black, and edematous. The cecum is moderately distended with gas and has an associated mesenteric blood clot.
Citation: Journal of the American Veterinary Medical Association 254, 2; 10.2460/javma.254.2.217
Photograph of the ileocecocolic junction of a 6.5-year-old cat that died after an episode of acute dyspnea. The serosa of the distal portion of the ileum, the entire cecum, and the proximal portion of the colon is diffusely dark red to black, and edematous. The cecum is moderately distended with gas and has an associated mesenteric blood clot.
Citation: Journal of the American Veterinary Medical Association 254, 2; 10.2460/javma.254.2.217
Photograph of the ileocecocolic junction of a 6.5-year-old cat that died after an episode of acute dyspnea. The serosa of the distal portion of the ileum, the entire cecum, and the proximal portion of the colon is diffusely dark red to black, and edematous. The cecum is moderately distended with gas and has an associated mesenteric blood clot.
Citation: Journal of the American Veterinary Medical Association 254, 2; 10.2460/javma.254.2.217
Formulate differential diagnoses from the history, clinical findings, and Figure 1—then turn the page→
Histopathologic Findings
Samples of multiple organs were collected, placed in neutral-buffered 10% formalin, and routinely processed for histologic examination. The ileocecocolic junction was expanded and partially effaced by a poorly demarcated, infiltrative neoplasm that extended mainly from the cecal and colonic submucosa and transmurally through the adjacent mesentery. Neoplastic cells were arranged in multiple, variably sized, anastomosing vascular channels or solid areas and were supported by thick collagen bundles (Figure 2). Vascular spaces were often filled with erythrocytes and fibrin strands. Neoplastic cells were elongate and had a moderate amount of eosinophilic, homogeneous cytoplasm with indistinct cell borders. Nuclei were oval and had finely to coarsely stippled chromatin with 1 or 2 distinct nucleoli. The mitotic count was 31 mitoses/2.4 mm2 (equivalent to 10 FN22-40X fields). Anisocytosis and anisokaryosis were moderate. Throughout the tumor were areas of hemorrhage with scattered hemosiderin-laden macrophages. Neoplastic cells had diffuse, strong membranous immunoreactivity for factor 8–related antigen (Figure 3). No notable changes were observed in the other examined organs.
Photomicrograph of a section from the ileocecocolic junction of the cat in Figure 1. The submucosa is expanded and effaced by neoplastic cells that have formed variably sized, anastomosing, blood-filled vascular channels, which are supported by collagenous bundles. H&E stain; bar = 100 μm.
Citation: Journal of the American Veterinary Medical Association 254, 2; 10.2460/javma.254.2.217
Photomicrograph of a section from the ileocecocolic junction of the cat in Figure 1. The submucosa is expanded and effaced by neoplastic cells that have formed variably sized, anastomosing, blood-filled vascular channels, which are supported by collagenous bundles. H&E stain; bar = 100 μm.
Citation: Journal of the American Veterinary Medical Association 254, 2; 10.2460/javma.254.2.217
Photomicrograph of a section from the ileocecocolic junction of the cat in Figure 1. The submucosa is expanded and effaced by neoplastic cells that have formed variably sized, anastomosing, blood-filled vascular channels, which are supported by collagenous bundles. H&E stain; bar = 100 μm.
Citation: Journal of the American Veterinary Medical Association 254, 2; 10.2460/javma.254.2.217
Photomicrograph of a section from the ileocecocolic junction of the cat in Figure 1 following immunohistochemical testing for factor 8–related antigen. The neoplastic cells have strong membranous immunoreactivity to factor 8–related antigen. Factor 8–related antigen immunohistochemical reaction; bar = 50 μm.
Citation: Journal of the American Veterinary Medical Association 254, 2; 10.2460/javma.254.2.217
Photomicrograph of a section from the ileocecocolic junction of the cat in Figure 1 following immunohistochemical testing for factor 8–related antigen. The neoplastic cells have strong membranous immunoreactivity to factor 8–related antigen. Factor 8–related antigen immunohistochemical reaction; bar = 50 μm.
Citation: Journal of the American Veterinary Medical Association 254, 2; 10.2460/javma.254.2.217
Photomicrograph of a section from the ileocecocolic junction of the cat in Figure 1 following immunohistochemical testing for factor 8–related antigen. The neoplastic cells have strong membranous immunoreactivity to factor 8–related antigen. Factor 8–related antigen immunohistochemical reaction; bar = 50 μm.
Citation: Journal of the American Veterinary Medical Association 254, 2; 10.2460/javma.254.2.217
Morphologic Diagnosis and Case Summary
Morphologic diagnosis and case summary: ileocecocolic hemangiosarcoma (HSA) with acute hemoperitoneum in a cat.
Comments
In the case described in the present report, the diagnosis of ileocecocolic HSA was made on the basis of the gross and histopathologic findings. Diagnostic confirmation was achieved by immunohistochemical testing, which revealed that the neoplastic cells had diffuse factor 8–related antigen immunoreactivity. Immunohistochemical testing is not usually necessary for diagnostic confirmation in typical cases of HSA; however, less differentiated subsets of these tumors, such as epithelioid HSAs, may require immunohistochemical findings to determine a final diagnosis.1–3 Factor 8–related antigen is a reliable immunohistochemical marker for HSA, and evidence of factor 8–related antigen immunoreactivity in the neoplastic tissue sections from the cat of the present report was used for diagnostic confirmation. Assessments with other endothelial immunomarkers, including CD31 and PROX-1, may also be used in suspected cases of HSA.4,5
Hemangiosarcoma is a malignant endothelial neoplasm that develops frequently in dogs, uncommonly in cats, and rarely in other domesticated animal species.2,3 In dogs and cats, these tumors typically affect adult to older animals, although HSA can occasionally develop in younger animals.2 Hemangiosarcomas in dogs and cats are usually classified as nonvisceral (cutaneous or subcutaneous) or visceral on the basis of the location of the tumors.2,3 Regardless of location, tumors can be single or multiple and can affect many sites on the skin and in internal organs.2,3
In dogs, nonvisceral HSAs mainly affect the skin of the ventral portion of the abdomen, limbs, dorsum, and head or neck.3 In cats, nonvisceral HSAs mainly affect the head, limbs, thorax, and flanks.6 A causal relationship has been established between cutaneous HSA and chronic UV light exposure or, less often, the presence of foreign bodies.2,7 Cases of visceral HSA in dogs and cats are usually multicentric at the time of diagnosis.2–6,8 Visceral HSAs develop mainly in the spleen, heart, and liver in dogs2,3 and in the intestines, liver, and abdominal lymph nodes in cats.6,8,9 Although the etiopathogenesis of visceral HSA remains unclear, intraoperative radiation therapy, genetic mutations, and sex-related differences have been proposed as possible contributing factors but no definitive cause-effect correlation has been proven to date.2 Similar to what was described for the cat of the present report, clinical signs related to visceral HSA are typically acute and variable, including lethargy, anorexia, vomiting, dehydration, dyspnea, tachycardia, and abdominal distention.4,5,8–10 Tumors may also cause hematologic disorders, such as thrombosis and acute or chronic anemia as a result of rapid or slow tumor hemorrhage, respectively.2–4,8 The cause of death for the cat of the present report was acute hemoabdomen caused by rupture of the ileocecocolic neoplasm.
In cats, the overall incidence of cutaneous and visceral HSA is low, representing 0.5% to 2% of all feline neoplasms.2,6,9 Consistent with veterinary medical literature findings, a search of the University of Georgia Department of Pathology and Athens Veterinary Diagnostic Laboratory web-based record system retrieved records of 113 cats with HSA among 6,440 (1.7%) cases of feline neoplasia over the last 8 years. Of those 113 cases of HSA, only 14 (12%) involved visceral HSA. Most visceral HSAs in cats reportedly affect the intestines, and the ileocecocolic junction has been indicated as a predisposed site for the development of these tumors in cats.4–6,8 This pattern of affected sites was apparent in the cat of the present report and in 2 additional feline cases retrieved from our database search. Compared with published information indicating that the intestines, liver, and abdominal lymph nodes are organs predisposed to visceral HSA in cats, the data gleaned from our archive search were fairly comparable; among the 14 cats with visceral HSA identified, affected organs included the liver (n = 6), mesentery (5), small intestine (3), spleen (3), thoracic organs (3), large intestine (2), ileocecocolic junction (2), mesenteric lymph node (1), and brain (1). It is important to highlight that of these 14 tumors, 8 were multicentric and 6 were focal. Also, the data retrieved from our archive search indicated that the age of affected cats at the time of evaluation was 2 to 17 years and that there was no evident sex or breed predisposition, findings that reflected published information.3,9
Surgical excision remains the preferred initial treatment in cases of HSA, and its success is closely linked to the location of the tumor, with cutaneous tumors being more easily resected than are visceral tumors. Although cutaneous tumors can be surgically removed, subcutaneous and visceral tumors are typically more aggressive and affected animals have a poor prognosis.2,6 Radiation therapy and chemotherapy can also be used as palliative treatment after surgery, but most research has been conducted in dogs, and little is known about the effects of such palliative treatments in cats with HSA.2
References
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