Image Gallery: Primary & Metastatic Tumors Part 1

Figure 1A Canine lung tumor

In these 3-view thoracic radiographs of an 8-year-old neutered male boxer with a lung tumor, a large soft tissue mass visibly extends to the lung lobe margins, nearly causing complete consolidation of the right middle lung lobe. Several closely spaced air bronchograms at the caudal margin of the mass are consistent with atelectasis caused by the expansile nature of the mass (Figure 1A; arrows). The apparent right mediastinal shift (ie, shifting of the cardiac silhouette to the right) in the ventrodorsal view (Figure 1C) is, at least in part, due to a moderate degree of patient rotation.

This patient underwent a right intercostal thoracotomy and lung lobectomy for tumor resection. On exposure of the thoracic cavity during surgery, it was found that the tumor was in contact with the right side of the heart, and, accordingly, occasional ventricular arrhythmias (ie, 3-4 per minute) were noted. A narrowly excised low-grade pulmonary carcinoma was confirmed via histopathology.

FIGURE 1B Canine lung tumor 

In these 3-view thoracic radiographs of an 8-year-old neutered male boxer with a lung tumor, a large soft tissue mass visibly extends to the lung lobe margins, nearly causing complete consolidation of the right middle lung lobe. Several closely spaced air bronchograms at the caudal margin of the mass are consistent with atelectasis caused by the expansile nature of the mass (Figure 1A; arrows). The apparent right mediastinal shift (ie, shifting of the cardiac silhouette to the right) in the ventrodorsal view (Figure 1C) is, at least in part, due to a moderate degree of patient rotation.

This patient underwent a right intercostal thoracotomy and lung lobectomy for tumor resection. On exposure of the thoracic cavity during surgery, it was found that the tumor was in contact with the right side of the heart, and, accordingly, occasional ventricular arrhythmias (ie, 3-4 per minute) were noted. A narrowly excised low-grade pulmonary carcinoma was confirmed via histopathology.

FIGURE 1C Canine lung tumor 

In these 3-view thoracic radiographs of an 8-year-old neutered male boxer with a lung tumor, a large soft tissue mass visibly extends to the lung lobe margins, nearly causing complete consolidation of the right middle lung lobe. Several closely spaced air bronchograms at the caudal margin of the mass are consistent with atelectasis caused by the expansile nature of the mass (Figure 1A; arrows). The apparent right mediastinal shift (ie, shifting of the cardiac silhouette to the right) in the ventrodorsal view (Figure 1C) is, at least in part, due to a moderate degree of patient rotation.

This patient underwent a right intercostal thoracotomy and lung lobectomy for tumor resection. On exposure of the thoracic cavity during surgery, it was found that the tumor was in contact with the right side of the heart, and, accordingly, occasional ventricular arrhythmias (ie, 3-4 per minute) were noted. A narrowly excised low-grade pulmonary carcinoma was confirmed via histopathology.

Figure 2A Cat after removal of a squamous cell carcinoma from the second digit of the left forepaw 

A 14-year-old neutered male domestic shorthair cat was presented for consultation after removal of a squamous cell carcinoma from the second digit of the left forepaw. These 3-view thoracic radiographs reveal a soft tissue opacity with poorly defined margins (white arrows) and a central air lucency (Figure 2C; black arrow) in the right caudal lung lobe. Based on these findings, which confirmed digit carcinoma and a large pulmonary tumor, this patient was diagnosed with feline lung-digit syndrome, a condition in which a primary lung tumor metastasizes to a digit.¹ In one study, lameness was the only observed clinical sign (ie, no respiratory signs were observed)²; therefore, it is critical to obtain thoracic radiographs for a cat presented with a digit tumor.

FIGURE 2B Cat after removal of a squamous cell carcinoma from the second digit of the left forepaw 

A 14-year-old neutered male domestic shorthair cat was presented for consultation after removal of a squamous cell carcinoma from the second digit of the left forepaw. These 3-view thoracic radiographs reveal a soft tissue opacity with poorly defined margins (white arrows) and a central air lucency (Figure 2C; black arrow) in the right caudal lung lobe. Based on these findings, which confirmed digit carcinoma and a large pulmonary tumor, this patient was diagnosed with feline lung-digit syndrome, a condition in which a primary lung tumor metastasizes to a digit.¹ In one study, lameness was the only observed clinical sign (ie, no respiratory signs were observed)²; therefore, it is critical to obtain thoracic radiographs for a cat presented with a digit tumor.

FIGURE 2C Cat after removal of a squamous cell carcinoma from the second digit of the left forepaw 

A 14-year-old neutered male domestic shorthair cat was presented for consultation after removal of a squamous cell carcinoma from the second digit of the left forepaw. These 3-view thoracic radiographs reveal a soft tissue opacity with poorly defined margins (white arrows) and a central air lucency (Figure 2C; black arrow) in the right caudal lung lobe. Based on these findings, which confirmed digit carcinoma and a large pulmonary tumor, this patient was diagnosed with feline lung-digit syndrome, a condition in which a primary lung tumor metastasizes to a digit.¹ In one study, lameness was the only observed clinical sign (ie, no respiratory signs were observed)²; therefore, it is critical to obtain thoracic radiographs for a cat presented with a digit tumor.

Figure 3A Cytologically diagnosed thymoma in a cat

Three-view thoracic radiographs were obtained of a 12-year-old spayed Siamese cat with a cytologically diagnosed thymoma. As seen on the ventrodorsal view (Figure 3C), the cranial mediastinum is widened, with a large, ill-defined soft tissue opacity (ie, the previously diagnosed thymoma) throughout the cranial thorax, which has caudally displaced the cardiac silhouette and deviated the trachea to the right. Diffuse alveolar consolidations (suspected to be atelectasis, as clinical signs typically associated with pneumonia were lacking) are present throughout the right cranial, right middle, and left cranial lung lobes on the ventrodorsal view (Figure 3C; arrows). A moderate diffuse bronchial pattern (presumed to be chronic lower airway disease) can also be noted throughout the remaining aerated lung lobes on the left lateral view (Figure 3B; arrows). This particular tumor was deemed inoperable; thus, radiation therapy was recommended.

FIGURE 3B Cytologically diagnosed thymoma in a cat

Three-view thoracic radiographs were obtained of a 12-year-old spayed Siamese cat with a cytologically diagnosed thymoma. As seen on the ventrodorsal view (Figure 3C), the cranial mediastinum is widened, with a large, ill-defined soft tissue opacity (ie, the previously diagnosed thymoma) throughout the cranial thorax, which has caudally displaced the cardiac silhouette and deviated the trachea to the right. Diffuse alveolar consolidations (suspected to be atelectasis, as clinical signs typically associated with pneumonia were lacking) are present throughout the right cranial, right middle, and left cranial lung lobes on the ventrodorsal view (Figure 3C; arrows). A moderate diffuse bronchial pattern (presumed to be chronic lower airway disease) can also be noted throughout the remaining aerated lung lobes on the left lateral view (Figure 3B; arrows). This particular tumor was deemed inoperable; thus, radiation therapy was recommended.

FIGURE 3C Cytologically diagnosed thymoma in a cat

Three-view thoracic radiographs were obtained of a 12-year-old spayed Siamese cat with a cytologically diagnosed thymoma. As seen on the ventrodorsal view (Figure 3C), the cranial mediastinum is widened, with a large, ill-defined soft tissue opacity (ie, the previously diagnosed thymoma) throughout the cranial thorax, which has caudally displaced the cardiac silhouette and deviated the trachea to the right. Diffuse alveolar consolidations (suspected to be atelectasis, as clinical signs typically associated with pneumonia were lacking) are present throughout the right cranial, right middle, and left cranial lung lobes on the ventrodorsal view (Figure 3C; arrows). A moderate diffuse bronchial pattern (presumed to be chronic lower airway disease) can also be noted throughout the remaining aerated lung lobes on the left lateral view (Figure 3B; arrows). This particular tumor was deemed inoperable; thus, radiation therapy was recommended.

Figure 4 Polyuria and polydipsia secondary to severe hypercalcemia

A single left lateral thoracic radiograph was obtained of a 7-year-old neutered male Siberian husky presented for polyuria and polydipsia secondary to severe hypercalcemia. There is increased soft tissue opacity in the cranial thorax, with a well-defined, convex, mass-like caudal margin. Focal, slight dorsal deviation of the trachea is present in the cranial thorax. Ultrasound-guided fine-needle aspiration confirmed large-cell lymphoma. PCR for antigen receptor rearrangement testing of needle aspirate samples from this mediastinal mass confirmed lymphoma with T-cell clonality. The patient was started on aggressive fluid therapy (0.9% NaCl) and corticosteroids to correct dehydration and to promote calciuresis before initiation of chemotherapy. The serum calcium level (both total and ionized) normalized within 24 hours. 

Figure 5A Advanced pulmonary metastasis in a dog with osteosarcoma of the left proximal humerus 

These 3-view thoracic radiographs illustrate advanced pulmonary metastasis in a 10-year-old neutered male Labrador retriever with osteosarcoma of the left proximal humerus. There are numerous, variably sized, multifocal, and—in some areas—coalescing, round, soft tissue nodules throughout all lung lobes. The primary tumor is visible as an aggressive osteolytic/osteoproliferative lesion in the left proximal humerus on the left lateral view (Figure 5A; arrows).

FIGURE 5B Advanced pulmonary metastasis in a dog with osteosarcoma of the left proximal humerus 

These 3-view thoracic radiographs illustrate advanced pulmonary metastasis in a 10-year-old neutered male Labrador retriever with osteosarcoma of the left proximal humerus. There are numerous, variably sized, multifocal, and—in some areas—coalescing, round, soft tissue nodules throughout all lung lobes. The primary tumor is visible as an aggressive osteolytic/osteoproliferative lesion in the left proximal humerus on the left lateral view (Figure 5A; arrows).

FIGURE 5C Advanced pulmonary metastasis in a dog with osteosarcoma of the left proximal humerus 

These 3-view thoracic radiographs illustrate advanced pulmonary metastasis in a 10-year-old neutered male Labrador retriever with osteosarcoma of the left proximal humerus. There are numerous, variably sized, multifocal, and—in some areas—coalescing, round, soft tissue nodules throughout all lung lobes. The primary tumor is visible as an aggressive osteolytic/osteoproliferative lesion in the left proximal humerus on the left lateral view (Figure 5A; arrows).

Figure 6A Oral melanoma

These 3-view thoracic radiographs are from an 8-year-old neutered male golden retriever with a multilobulated and darkly pigmented gingival mass arising from the right mandible. There are numerous medium-to-large–sized round soft tissue nodules present throughout all lung lobes, which is consistent with pulmonary metastatic disease. Visible skeletal structures are relatively unremarkable. Subsequent fine-needle aspirate cytology of the oral mass confirmed malignant melanoma.

FIGURE 6B Oral melanoma

These 3-view thoracic radiographs are from an 8-year-old neutered male golden retriever with a multilobulated and darkly pigmented gingival mass arising from the right mandible. There are numerous medium-to-large–sized round soft tissue nodules present throughout all lung lobes, which is consistent with pulmonary metastatic disease. Visible skeletal structures are relatively unremarkable. Subsequent fine-needle aspirate cytology of the oral mass confirmed malignant melanoma.

FIGURE 6C Oral melanoma

These 3-view thoracic radiographs are from an 8-year-old neutered male golden retriever with a multilobulated and darkly pigmented gingival mass arising from the right mandible. There are numerous medium-to-large–sized round soft tissue nodules present throughout all lung lobes, which is consistent with pulmonary metastatic disease. Visible skeletal structures are relatively unremarkable. Subsequent fine-needle aspirate cytology of the oral mass confirmed malignant melanoma.

Figure 7A Pulmonary metastatic disease in a dog with prostatic carcinoma

These 3-view thoracic radiographs illustrate pulmonary metastatic disease in a 13-year-old neutered male Labrador retriever with a mineralized prostatic mass cytologically consistent with carcinoma. There are multiple, small round soft tissue nodules throughout all lung lobes, including: an ≈1.0-cm nodule superimposed over the end of the third rib, an ≈0.9 cm nodule superimposed over the fourth rib, and an ≈0.5-cm nodule at the distal aspect of the first intercostal space as seen on the right lateral view (Figure 7A; arrows); and an ≈1.7 × 1.8-cm nodule just ventral to the body of T5, an ≈1.1-cm nodule superimposed over the aorta at the level of T7 as seen on the left lateral view (Figure 7B; arrows). A mild, diffuse bronchial pattern—presumed to be chronic lower airway disease—is present throughout all lung lobes.

Figure 7B Pulmonary metastatic disease in a dog with prostatic carcinoma

These 3-view thoracic radiographs illustrate pulmonary metastatic disease in a 13-year-old neutered male Labrador retriever with a mineralized prostatic mass cytologically consistent with carcinoma. There are multiple, small round soft tissue nodules throughout all lung lobes, including: an ≈1.0-cm nodule superimposed over the end of the third rib, an ≈0.9 cm nodule superimposed over the fourth rib, and an ≈0.5-cm nodule at the distal aspect of the first intercostal space as seen on the right lateral view (Figure 7A; arrows); and an ≈1.7 × 1.8-cm nodule just ventral to the body of T5, an ≈1.1-cm nodule superimposed over the aorta at the level of T7 as seen on the left lateral view (Figure 7B; arrows). A mild, diffuse bronchial pattern—presumed to be chronic lower airway disease—is present throughout all lung lobes.

Figure 7C Pulmonary metastatic disease in a dog with prostatic carcinoma

These 3-view thoracic radiographs illustrate pulmonary metastatic disease in a 13-year-old neutered male Labrador retriever with a mineralized prostatic mass cytologically consistent with carcinoma. There are multiple, small round soft tissue nodules throughout all lung lobes, including: an ≈1.0-cm nodule superimposed over the end of the third rib, an ≈0.9 cm nodule superimposed over the fourth rib, and an ≈0.5-cm nodule at the distal aspect of the first intercostal space as seen on the right lateral view (Figure 7A; arrows); and an ≈1.7 × 1.8-cm nodule just ventral to the body of T5, an ≈1.1-cm nodule superimposed over the aorta at the level of T7 as seen on the left lateral view (Figure 7B; arrows). A mild, diffuse bronchial pattern—presumed to be chronic lower airway disease—is present throughout all lung lobes.

Figure 8 Pulmonary metastatic disease in a dog with splenic hemangiosarcoma

A ventrodorsal and a right lateral thoracic radiograph illustrate pulmonary metastatic disease in a 14-year-old spayed German shepherd dog with splenic hemangiosarcoma. There are multifocal-to-coalescing and, in some places, miliary patterns of small round soft tissue nodules throughout all lung fields (arrows).

Figure 9A Multicentric high-grade B-cell lymphoma

Three-view thoracic radiographs of a 4-year-old neutered male golden retriever were obtained on initial diagnosis of multicentric high-grade B-cell lymphoma. In the right lateral view (Figure 9A), there is a moderate-to-marked unstructured interstitial-to-reticulonodular pulmonary pattern present throughout the lungs (arrows). In the left lateral view (Figure 9B), the sternal lymph node is mildly enlarged (arrows). Pulmonary involvement, which is radiographically evident, was consistent with Stage V presentation.

Figure 9B Multicentric high-grade B-cell lymphoma

Three-view thoracic radiographs of a 4-year-old neutered male golden retriever were obtained on initial diagnosis of multicentric high-grade B-cell lymphoma. In the right lateral view (Figure 9A), there is a moderate-to-marked unstructured interstitial-to-reticulonodular pulmonary pattern present throughout the lungs (arrows). In the left lateral view (Figure 9B), the sternal lymph node is mildly enlarged (arrows). Pulmonary involvement, which is radiographically evident, was consistent with Stage V presentation.

Figure 9C Multicentric high-grade B-cell lymphoma

Three-view thoracic radiographs of a 4-year-old neutered male golden retriever were obtained on initial diagnosis of multicentric high-grade B-cell lymphoma. In the right lateral view (Figure 9A), there is a moderate-to-marked unstructured interstitial-to-reticulonodular pulmonary pattern present throughout the lungs (arrows). In the left lateral view (Figure 9B), the sternal lymph node is mildly enlarged (arrows). Pulmonary involvement, which is radiographically evident, was consistent with Stage V presentation.

Figure 10A Multicentric high-grade B-cell lymphoma after 1 month of multiagent chemotherapy

These 2-view thoracic radiographs (obtained from same patient as in Figure 9) were obtained a month after starting multiagent chemotherapy directed at B-cell lymphoma. In the left lateral view (Figure 10A), the sternal lymph node has decreased in size (arrow). In the ventrodorsal view (Figure 10B), the pulmonary parenchyma appears normal, which illustrates a marked improvement over the moderate-to-severe diffuse unstructured interstitial pulmonary pattern previously noted. When these radiographs were obtained, the patient was deemed to be in complete clinical remission based on physical examination (ie, resolution of peripheral lymphadenopathy) and thoracic radiography findings.

Figure 10B Multicentric high-grade B-cell lymphoma after 1 month of multiagent chemotherapy

These 2-view thoracic radiographs (obtained from same patient as in Figure 9) were obtained a month after starting multiagent chemotherapy directed at B-cell lymphoma. In the left lateral view (Figure 10A), the sternal lymph node has decreased in size (arrow). In the ventrodorsal view (Figure 10B), the pulmonary parenchyma appears normal, which illustrates a marked improvement over the moderate-to-severe diffuse unstructured interstitial pulmonary pattern previously noted. When these radiographs were obtained, the patient was deemed to be in complete clinical remission based on physical examination (ie, resolution of peripheral lymphadenopathy) and thoracic radiography findings.

Figure 11A Pulmonary metastasis secondary to thyroid carcinoma

These 2-view thoracic radiographs illustrate pulmonary metastasis secondary to thyroid carcinoma in a 15-year-old spayed domestic shorthair cat. Multiple medium-to-large–sized, round-to-ovoid, somewhat irregularly marginated soft tissue masses are present throughout the lung fields. There is also evidence of aerophagia, visible by the gas-distended stomach.

Figure 11B Pulmonary metastasis secondary to thyroid carcinoma

These 2-view thoracic radiographs illustrate pulmonary metastasis secondary to thyroid carcinoma in a 15-year-old spayed domestic shorthair cat. Multiple medium-to-large–sized, round-to-ovoid, somewhat irregularly marginated soft tissue masses are present throughout the lung fields. There is also evidence of aerophagia, visible by the gas-distended stomach.

Figure 12A Dog after urethral stent placed to alleviate a complete urinary obstruction secondary to prostatic carcinoma 

This 2-view contrast urethrogram shows a 12-year-old neutered male miniature schnauzer just after urethral stent placement for alleviation of a complete urinary obstruction secondary to prostatic carcinoma. The urinary bladder is cranially displaced and moderately distended with radiopaque contrast media. Visible in the left lateral view (Figure 12B), a large, round soft tissue mass caudal to the contrast-filled bladder is consistent with a prostatic mass. A metallic stent (Figure 12B; arrows) spans the entire length of the prostatic urethra and extends a short distance into the trigone of the urinary bladder. The enlarged prostate has caused left lateral displacement of the descending colon. The patient appeared to urinate comfortably immediately after stent placement.

FIGURE 12B Dog after urethral stent placed to alleviate a complete urinary obstruction secondary to prostatic carcinoma 

This 2-view contrast urethrogram shows a 12-year-old neutered male miniature schnauzer just after urethral stent placement for alleviation of a complete urinary obstruction secondary to prostatic carcinoma. The urinary bladder is cranially displaced and moderately distended with radiopaque contrast media. Visible in the left lateral view (Figure 12B), a large, round soft tissue mass caudal to the contrast-filled bladder is consistent with a prostatic mass. A metallic stent (Figure 12B; arrows) spans the entire length of the prostatic urethra and extends a short distance into the trigone of the urinary bladder. The enlarged prostate has caused left lateral displacement of the descending colon. The patient appeared to urinate comfortably immediately after stent placement.

Figure 13 Mucinous colonic carcinoma

This single lateral abdominal radiograph shows a histologically diagnosed mucinous colonic carcinoma in a 12-year-old neutered male miniature pinscher. Stippled mineralization is present throughout the pelvic canal and is superimposed on the caudal descending colon and rectum (arrows). The serosal margins of the caudal descending colon within the pelvic canal are poorly defined; in the pelvic canal, there is also increased soft tissue opacity beyond that associated with more mottled and normal-appearing feces in the cranial descending colon. This mineralized mass is most consistent with a primary tumor of the descending colon. Small bubbles of free air in the peritoneal cavity and caudal ventral abdominal skin staples are consistent with a recent laparotomy.