History
A 9-year-old spayed female Italian Greyhound was evaluated for shallow breathing and a dry cough of 2 days' duration. Three weeks prior to evaluation, the dog completed a 4-month multidrug chemotherapy protocol for completely excised T-cell jejunal lymphoma. Tachypnea and marked abdominal expiratory effort were noted. Increased expiratory lung sounds were found in all quadrants during auscultation of the thorax. Findings on abdominal palpation were normal. Results of a CBC and serum biochemical analyses were within reference limits. Thoracic radiographs were obtained (Figure 1).
Right lateral (A) and ventrodorsal (B) radiographic views of the thorax of a 9-year-old spayed female dog evaluated for shallow breathing and a dry cough of 2 days' duration.
Citation: Journal of the American Veterinary Medical Association 239, 8; 10.2460/javma.239.8.1055
Right lateral (A) and ventrodorsal (B) radiographic views of the thorax of a 9-year-old spayed female dog evaluated for shallow breathing and a dry cough of 2 days' duration.
Citation: Journal of the American Veterinary Medical Association 239, 8; 10.2460/javma.239.8.1055
Right lateral (A) and ventrodorsal (B) radiographic views of the thorax of a 9-year-old spayed female dog evaluated for shallow breathing and a dry cough of 2 days' duration.
Citation: Journal of the American Veterinary Medical Association 239, 8; 10.2460/javma.239.8.1055
Determine whether additional imaging studies are required, or make your diagnosis from Figure 1—then turn the page →
Diagnostic Imaging Findings and Interpretation
There is a smooth, lobulated, and broad-based soft tissue mass within the middle and right caudal aspect of the thoracic cavity that silhouettes with the diaphragm and caudal vena cava (Figure 2). The right mainstem bronchus is collapsed. A round-to-oval soft tissue opacity dorsal to the second sternebra is consistent with sternal lymphadenopathy. Differential diagnoses for the soft tissue mass include a diaphragmatic mass, lung lobe mass, and diaphragmatic hernia. Differential diagnoses for sternal lymphadenomegaly include neoplasia and reactive lymphadenopathy.
Same radiographic views as in Figure 1. On the ventrodorsal view, a lobulated mass with a broad base extending toward the diaphragm is evident. On the lateral view, the soft tissue opacity extends dorsally with round borders caudal to the carina, and sternal lymphadenomegaly is prominent. The caudal vena cava is obscured. LN = Enlarged lymph node. M = Mass (soft tissue opacity).
Citation: Journal of the American Veterinary Medical Association 239, 8; 10.2460/javma.239.8.1055
Same radiographic views as in Figure 1. On the ventrodorsal view, a lobulated mass with a broad base extending toward the diaphragm is evident. On the lateral view, the soft tissue opacity extends dorsally with round borders caudal to the carina, and sternal lymphadenomegaly is prominent. The caudal vena cava is obscured. LN = Enlarged lymph node. M = Mass (soft tissue opacity).
Citation: Journal of the American Veterinary Medical Association 239, 8; 10.2460/javma.239.8.1055
Same radiographic views as in Figure 1. On the ventrodorsal view, a lobulated mass with a broad base extending toward the diaphragm is evident. On the lateral view, the soft tissue opacity extends dorsally with round borders caudal to the carina, and sternal lymphadenomegaly is prominent. The caudal vena cava is obscured. LN = Enlarged lymph node. M = Mass (soft tissue opacity).
Citation: Journal of the American Veterinary Medical Association 239, 8; 10.2460/javma.239.8.1055
Abdominal ultrasonography revealed an avascular, smooth, triangular region of homogenous tissue along the right craniodorsal portion of the body wall, hypoechoic to the liver.
Computed tomography of the thorax and cranial aspect of the abdomen revealed a 1.0-cm-diameter, irregularly marginated, contrast-enhancing soft tissue nodule within the right caudal lung lobe. A large attenuating, non–contrast-enhancing, sickle-shaped soft tissue mass was also present within the right diaphragmatic crus. The mass compressed the caudal vena cava at the hiatus and protruded through the hiatus, compressed and displaced the right liver lobes toward midline, and wrapped around the liver dorsally and ventrally (Figure 3). Cytologic evaluation of the mass revealed probable lymphoma.
Transverse computed tomographic image (A) of the cranial aspect of the abdomen of the same dog as in Figure 1 acquired after administration of iodinated contrast medium (the right side is to the reader's left). The liver and gallbladder (GB) are deviated medially by a non–contrast-enhancing mass (M) along the right diaphragmatic crus. The contrast-enhanced caudal vena cava (arrowhead) is compressed. A sagittally reformatted computed tomographic image (B) shows the non–contrast-enhancing mass (M) separating the caudal aspect of the thoracic cavity from the cranial aspect of the liver (L). The mass is cranial and ventral to the liver.
Citation: Journal of the American Veterinary Medical Association 239, 8; 10.2460/javma.239.8.1055
Transverse computed tomographic image (A) of the cranial aspect of the abdomen of the same dog as in Figure 1 acquired after administration of iodinated contrast medium (the right side is to the reader's left). The liver and gallbladder (GB) are deviated medially by a non–contrast-enhancing mass (M) along the right diaphragmatic crus. The contrast-enhanced caudal vena cava (arrowhead) is compressed. A sagittally reformatted computed tomographic image (B) shows the non–contrast-enhancing mass (M) separating the caudal aspect of the thoracic cavity from the cranial aspect of the liver (L). The mass is cranial and ventral to the liver.
Citation: Journal of the American Veterinary Medical Association 239, 8; 10.2460/javma.239.8.1055
Transverse computed tomographic image (A) of the cranial aspect of the abdomen of the same dog as in Figure 1 acquired after administration of iodinated contrast medium (the right side is to the reader's left). The liver and gallbladder (GB) are deviated medially by a non–contrast-enhancing mass (M) along the right diaphragmatic crus. The contrast-enhanced caudal vena cava (arrowhead) is compressed. A sagittally reformatted computed tomographic image (B) shows the non–contrast-enhancing mass (M) separating the caudal aspect of the thoracic cavity from the cranial aspect of the liver (L). The mass is cranial and ventral to the liver.
Citation: Journal of the American Veterinary Medical Association 239, 8; 10.2460/javma.239.8.1055
Comments
Abdominal exploratory surgery was performed with the intent of mass resection for diagnosis and palliation of progressive dyspnea and tachypnea. A large (5 × 10-cm) opaque soft tissue mass was found to be intimately associated with the diaphragm but also involved the caudal vena cava, caval hiatus, and right thoracic body wall. Complete removal of the mass was not possible; histologic examination of multiple full-thickness diaphragmatic biopsy specimens revealed T-cell lymphoma. The pulmonary nodule was not removed. Despite various chemotherapy protocols, the dog died approximately 90 days after surgery. Diaphragmatic masses are rare in dogs, with only 2 reports1,2 of primary diaphragmatic masses, both of which were histologically classified as peripheral nerve sheath tumors. Multiple imaging modalities, including computed tomography and magnetic resonance imaging, may aid in diagnosis.
References
1. Patterson CC, Perry RL, Steficek B. Malignant peripheral nerve sheath tumor of the diaphragm in a dog. J Am Anim Hosp Assoc 2008; 44:36–40.
2. Anderson GM, Dallaire A, Miller LM, et al. Peripheral nerve sheath tumor of the diaphragm with osseous differentiation in a one year-old dog. J Am Anim Hosp Assoc 1999; 35:319–322.
