History
An 11-year-old 5.4-kg (11.9-lb) castrated male domestic longhair cat was referred for evaluation of acute onset of weight loss, lethargy, and a palpable abdominal mass. The owners, who were out of town for 2 weeks, came home to find that their cat had lost a substantial amount of weight and was notably lethargic. The cat was evaluated by the primary care veterinarian, who palpated a left-sided, midabdominal mass, and immediately referred the cat.
On physical examination, the cat was bright, alert, and responsive. All vital signs were within reference limits and no abnormalities were found on thoracic auscultation. All lymph nodes were symmetric, normal in size, soft, and freely moveable on palpation. There was generalized muscle wasting, a poor coat, and an approximately 4-cm-diameter mass palpated in the midabdomen on the left side.
A CBC, serum biochemical analysis, and urinalysis were performed. On CBC determination, moderate mature neutrophilia (23,900 cells/μL; reference range, 2,000 to 12,000 cells/μL), mild monocytosis (1,300 cells/μL; reference range, 0 to 800 cells/μL), and mild normocytic, normochromic nonregenerative anemia (Hct, 30%; reference range, 31% to 48%) were detected. Serum biochemical analysis revealed mild hypoproteinemia (6.1 g/dL; reference range, 6.3 to 8.0 g/dL), mild hyperglycemia (184 mg/dL; reference range, 69 to 136 gm/dL), mild hypermagnesemia (3.8 mg/dL; reference range, 1.8 to 2.4 mg/dL), and mild hyponatremia (147 mEq/L; reference range, 149 to 158 mEq/L). Serum aspartate aminotransferase (64 U/L; reference range, 12 to 46 U/L) and creatine kinase (362 U/L; reference range, 21 to 275 U/L) activities were high. Serum creatinine (0.7 mg/dL; reference range, 0.8 to 2.0 mg/dL) concentration was slightly low. Urinalysis findings revealed minimally concentrated (urine specific gravity, 1.028), aciduric, mildly proteinuric (1+ protein on dipstick evaluation) urine with unremarkable sediment (ie, no evidence of hemorrhage or inflammation).
Three-view abdominal radiography was performed (Figure 1).
Left lateral (A), right lateral (B), and ventrodorsal (C) radiographic views of the abdomen of an 11-year-old 5.4-kg (11.9-lb) castrated male domestic longhair cat that was referred for evaluation of acute onset of weight loss, lethargy, and a palpable abdominal mass.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Left lateral (A), right lateral (B), and ventrodorsal (C) radiographic views of the abdomen of an 11-year-old 5.4-kg (11.9-lb) castrated male domestic longhair cat that was referred for evaluation of acute onset of weight loss, lethargy, and a palpable abdominal mass.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Left lateral (A), right lateral (B), and ventrodorsal (C) radiographic views of the abdomen of an 11-year-old 5.4-kg (11.9-lb) castrated male domestic longhair cat that was referred for evaluation of acute onset of weight loss, lethargy, and a palpable abdominal mass.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Diagnostic Imaging Findings and Interpretation
Ventrodorsal and lateral radiographic images of the abdomen reveal a moderately diffusely thickened stomach wall, causing caudal displacement of the transverse colon and small intestines. Pleural fissure lines and focal decreased abdominal serosal detail ventral to the stomach are evidence of bicavitary effusion, and there is a diffuse bronchial pattern in the observable portions of the lungs (Figure 2).
Same radiographic images as in Figure 1. The stomach wall is diffusely thickened (black arrows), as made evident by the gas within the stomach lumen that is seen continuing into the duodenum (white arrows). Pleural fissure lines (dashed arrows) and focal decreased serosal detail ventral to the stomach are evidence of bicavitary effusion.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Same radiographic images as in Figure 1. The stomach wall is diffusely thickened (black arrows), as made evident by the gas within the stomach lumen that is seen continuing into the duodenum (white arrows). Pleural fissure lines (dashed arrows) and focal decreased serosal detail ventral to the stomach are evidence of bicavitary effusion.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Same radiographic images as in Figure 1. The stomach wall is diffusely thickened (black arrows), as made evident by the gas within the stomach lumen that is seen continuing into the duodenum (white arrows). Pleural fissure lines (dashed arrows) and focal decreased serosal detail ventral to the stomach are evidence of bicavitary effusion.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Abdominal ultrasonography was performed for further evaluation. Diffuse stomach wall thickening with complete loss of wall layering within the fundus and body of the stomach is evident. The gastric wall in this area is heterogenous and hypoechoic. (Figure 3). There is a 20-mm-diameter, round, hypoechoic and heterogeneous lesion in the right cranial aspect of the abdomen suspected to be a regional lymph node (Figure 4). The mesentery surrounding this lesion is focally hyperechoic.
Transverse ultrasonographic image of the stomach of the cat in Figure 1. There is marked diffuse wall thickening, measuring (arrows) up to 25.9 mm, with complete loss of wall layering within the fundus and body of the stomach. The image was obtained transabdominally with a 3- to 11-MHz linear transducer.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Transverse ultrasonographic image of the stomach of the cat in Figure 1. There is marked diffuse wall thickening, measuring (arrows) up to 25.9 mm, with complete loss of wall layering within the fundus and body of the stomach. The image was obtained transabdominally with a 3- to 11-MHz linear transducer.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Transverse ultrasonographic image of the stomach of the cat in Figure 1. There is marked diffuse wall thickening, measuring (arrows) up to 25.9 mm, with complete loss of wall layering within the fundus and body of the stomach. The image was obtained transabdominally with a 3- to 11-MHz linear transducer.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Transverse ultrasonographic image of the intraabdominal mass in the right cranial aspect of the abdomen of the cat in Figure 1. The mass lesion is approximately 20 mm in diameter, round, hypoechoic, and heterogeneous. It is suspected to be a regional lymph node. There is a Doppler box surrounding the lesion, with a vessel dorsal to it. The image was obtained transabdominally with a 3- to 11-MHz linear transducer.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Transverse ultrasonographic image of the intraabdominal mass in the right cranial aspect of the abdomen of the cat in Figure 1. The mass lesion is approximately 20 mm in diameter, round, hypoechoic, and heterogeneous. It is suspected to be a regional lymph node. There is a Doppler box surrounding the lesion, with a vessel dorsal to it. The image was obtained transabdominally with a 3- to 11-MHz linear transducer.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Transverse ultrasonographic image of the intraabdominal mass in the right cranial aspect of the abdomen of the cat in Figure 1. The mass lesion is approximately 20 mm in diameter, round, hypoechoic, and heterogeneous. It is suspected to be a regional lymph node. There is a Doppler box surrounding the lesion, with a vessel dorsal to it. The image was obtained transabdominally with a 3- to 11-MHz linear transducer.
Citation: Journal of the American Veterinary Medical Association 253, 4; 10.2460/javma.253.4.409
Additional findings during ultrasonographic examination (images not provided) included a mild amount of anechoic fluid within the peritoneal space and pleural cavity adjacent to the diaphragm. The pyloric and intestinal wall thickness and layering and the remainder of the abdominal structures were ultrasonographically within reference limits.
The diffuse gastric mural mass in conjunction with regional lymphadenopathy and bicavitary effusion made the primary differential diagnoses gastric lymphoma or mastocytosis, followed by gastric adenocarcinoma or atypical leiomyosarcoma with metastatic and infiltrative lymphadenopathy. Granulomatous disease with reactive lymphadenopathy could not be ruled out without further diagnostic testing. The pleural and peritoneal effusions could represent an effusion of malignancy or inflammation, or could be secondary to hypoproteinemia. The diffuse bronchial pattern could represent chronic small airway disease or infiltrative neoplasia, such as lymphoma.
Treatment and Outcome
Results of cytologic evaluation of a fine needle aspirate of the mural mass and presumed lymph node confirmed the diagnosis of lymphoma. The owners elected palliative treatment with corticosteroids. The cat was euthanized 2 weeks later.
Comments
Lymphoma is the most common gastric tumor in cats.1 Common clinical signs include vomiting, weight loss, inappetence, and lethargy, and anemia is a common laboratory finding.1,2 A palpable abdominal mass is uncommon, and often the only ultrasonographic evidence of gastric lymphoma is an abnormality in the stomach wall, such as wall thickening and loss of the normal layering appearance, especially in the pyloric region.1–3 The origin of an abdominal mass is rarely revealed by palpation of the mass or on evaluation of regular survey radiographs because luminal fluid can mimic gastric and intestinal wall thickening. Therefore, ultrasonography is the diagnostic modality of choice for localizing and characterizing intra-abdominal masses.4 The case described in the present report is noteworthy in that the palpable mass was easily identified on radiographs as gastric in origin because of intraluminal gas within the stomach and duodenum causing a consistently irregular contour of the luminal wall in the ventrodorsal and both lateral radiographic views. This emphasizes the importance of obtaining both right and left lateral images for abdominal radiographic studies as the gas redistributes in the different areas of the stomach on the basis of laterality. In the cat of the present report, the gas redistribution, combined with the diffuse irregularity of the luminal and outer wall surfaces, allowed for the radiographic diagnosis of gastric wall thickening. Although ultrasonographic findings confirmed the presence of a gastric mural mass and allowed for guided tissue sampling to achieve a definitive diagnosis, the radiographic appearance of the stomach alone could have led to a similar outcome without pursuing further diagnostic testing in the cat of the present report.
References
1. Marolf AJ, Bachand AM, Sharber J, et al. Comparison of endoscopy and sonography findings in dogs and cats with histologically confirmed gastric neoplasia. J Small Anim Pract 2015;56:339–344.
2. Gustafson TL, Villamil A, Taylor B, et al. A retrospective study of feline gastric lymphoma in 16 chemotherapy-treated cats. J Am Anim Hosp Assoc 2014;50:46–52.
3. Pennick DG, Nyland TG, Kerr LY, et al. Ultrasonographic evaluation of gastrointestinal disease in small animals. Vet Radiol 1990;31:134–141.
4. Grooters AM, Biller DS, Ward H, et al. Ultrasonographic appearance of feline alimentary lymphoma. Vet Radiol Ultrasound 1994;35:468–472.
