Sample Abdominal Case Submission

Honey is a 7year old female spayed DLH with a recent history of vomiting and weight loss. She presented on 7/6/06, and her physical exam showed weight-10.75 pounds, BCS-4/5, temperature-100.1 ‘F, oral- mm’s pink, CRT-1 second, mild dental calculus and gingivitis, heart rate- 200bpm, respiratory rate-20 (growling), abdominal palpation-possible mass mid abdomen, may be stool. Integument, eyes, ears, musculoskeletal, urogenital- no significant findings.

Labwork:
CBC

Chemistry Profile

FeLV (ELISA)- Negative

Urinalysis

Radiographs:
Cranial abdomen is hazy, poor contrast. There is some gas containing material in the stomach that could be foreign material. The liver is prominently and somewhat irregularly enlarged. The kidneys appear slightly irregular, but not small. What little is showing of the lungs looks normal.

Differentials for poor cranial abdominal contrast include pancreatitis, peritonitis, bile leakage, cholecystitis, or even adhesions from previous disease. The changes in the stomach raise concern for foreign material. The symmetrical hepatomegaly with some irregularity and all the other findings warrant ultrasonographic clarification.

Images:

Liver- Normal in shape and size, with subtly increased echogenicity. There is free fluid in between the lobes, especially seen on the left. The gall bladder is normal in size and wall thickness, with anechoic bile and a tortuous common bile duct. This was traced toward the proximal duodenum and measured at 0.57cm, which is dilated, with normal width at less than 0.4cm. No obstruction could be identified.

Stomach- There is a large portion of the stomach wall that is greatly thickened, hypoechoic, and has lost the normal layering. The thickening is finely nodular and  involves the lesser curvature, the ventral and dorsal walls of the fundus and body, but not pylorus. The wall thickness measures approximately 2.6cm at its thickest. Gastric motility is decreased. There is also an enlarged hypoechoic gastric lymph node at approximately 1cm in diameter.

The pancreas is diffusely hypoechoic, appears slightly enlarged and has a slightly dilated duct for a cat this age, at 1.9mm in diameter. The distal end of the left limb of the pancreas is particularly hypoechoic.
The spleen is normal is size, shape and echogenicity. There is a small amount of fluid around it and the splenic lymph nodes are slightly hypoechoic and slightly enlarged.

Both kidneys are slightly enlarged and misshapen, and have decreased corticomedullary distinction. The cortical tissue is granular and slightly hyperechoic, diffusely in the right and more patchy in the left. There is subtle hyperechoic perirenal tissue.

The bladder is normal in shape, wall thickness, with anechoic urine. There is a scant amount of free fluid evident at the cranial wall. The sublumbar lymph nodes are normal.

The intestines appear normal, although there is a rare jejunal lymph node that is hypoechoic.

The stomach wall, liver, and the left kidney were aspirated with ultrasound guidance, and the free fluid was also sampled. All but the liver slides were submitted for cytologic evaluation. The liver slides showed hepatocytes with significant vacuolar change, but no other inflammatory or neoplastic cells were seen.

Interpretation Summary:

The mural changes in the stomach are most likely neoplastic given the severity and asymmetry, with lymphoma being the most likely. There are also changes suggestive of pancreatitis. The free fluid may be secondary to neoplasia, portal hypertension, or due to the pancreatitis, or a combination. The dilated common bile duct is most likely secondary to the pancreatitis, and was difficult to trace directly into the duodenum, but was also difficult to identify the exact location of an obstruction. The mildly increased liver echogenicity and vacuolar change in the hepatocytes are consistent with secondary hepatic lipidosis, but diffusely infiltrative lymphoma is also a possibility.

The changes in the kidneys are also concerning for lymphoma. FIP is also a possibility.

Cytology and Fluid Analysis:  

Fluid: Color                             Dark Orange-Red/Opaque
            Specific Gravity          1.021
            WBC                           <50/uL
            RBC                            150,000/uL
            Protein                                    3.5gm/dL
            Other                           Clot detected in Lavender Top Tube

Fluid Cytology:

Description: The slides and cytospin are adequately cellular and contain neutrophils, macrophages, and mesothelial cells. A few small mature lymphs are also seen. The mesothelial cells are moderately reactive and the neutrophils are in good morphologic shape. No bacteria or other infectious agents are observed, nor are any neoplastic cells seen.

Microscopic Findings: Modified Transudate

Comments: This non-inflammatory effusion is likely the result of chronic liver disease, however, it could also be caused by congestive heart failure, chronic renal disease, intestinal disease or neoplasia.

Cytology: Source: Kidney
Description: The slides are adequately cellular with a diffuse background of peripheral blood containing numerous renal tubular epithelial cells. These are             normal in appearance. In addition, there is a moderately dense population of immature lymphoid cells, many of which resemble lymphoblasts. No bacteria or other infectious agents can be found.

Microscopic Findings: Renal Lymphoma, probable high grade.

Comments: The dense infiltrate of immature lymphoid cells is consistent with a high grade lymphoma, however, if chemotherapy is an option for this cat, a biopsy with histopathologic evaluation is recommended to confirm tumor grading prior to onset of treatment.

Cytology: Source: Stomach Mass
Description: The slides are adequately cellular and contain a fairly monomorphic population of immature lymphoblasts. These cells have round to slightly irregularly shaped nuclei and a scant amount of basophilic circumferential cytoplasm. Most of the nuclei have prominent nucleoli. Lymphoglandular bodies are also noted. Some macrophages containing phagocytized cellular debris are also present.

Microscopic Findings: Lymphoma – High Grade (Lymphoblastic).

Comments: Wedge biopsy with histopathologic evaluation would be helpful for grading of the neoplasm prior to the onset of chemotherapy. Immunocytochemistry would be also of assistance in determining if the neoplastic lymphoid cells are of B-cell or T-cell origin.

Final Outcome:

Honey was euthanized on 7/13/06. No necropsy was performed.

Discussion:

This was a case of gastric lymphoma that likely spread to the lymph nodes and kidneys. The pancreatitis and hepatic lipidosis were complicating factors, and it is unknown if there was involvement with these organs by the lymphoma, or not, since the liver aspirates were not submitted due to financial reasons, and the pancreas was not aspirated.

Ultrasound is a highly effective, noninvasive tool for the evaluation of and identifying lesions consistent with alimentary lymphoma in cats. (1,2) The most common ultrasonographic findings were transmural thickening associated with diffuse loss of normal wall layering, reduced wall echogenicity, localized decreased motility, and moderate regional lymphadenopathy.(3) All of these features were found in this case in a large portion of the gastric wall. The notable features in this case were that the transmural changes had not yet become fully circumferential, in that there was a portion of the greater curvature of the stomach that was not affected. Also, there was a nodular texture to the edges of the gastric mass, despite being homogenously hypoechoic. This feature makes this case consistent with the transmural-nodular type of ultrasonographic features noted in feline alimentary lymphoma. (2) These features also help to differentiate
lymphoma from leiomyosarcoma, which has been described in a cat as an irregular
asymmetric mass with inhomogeneous echogenicity. The area of lymphomatous infiltration is hypoechoic because it contains a uniform cell population without much reactionary fibrous tissue. This results in a homogeneous tissue medium with minimal differences in acoustic impedance, thus producing an anechoic to hypoechoic image. (1)

It must be stressed that these changes are helpful in differentiating lymphoma from other neoplastic and even non-neoplastic diseases, but it is not diagnostic. Fine needle aspirates or biopsies must be obtained and accurately interpreted to make the diagnosis. Ultrasonography safely allows fine needle aspiration with ultrasound guidance even if the lesion is not palpable. Since lymphomas tend to exfoliate well, the diagnosis can frequently be made on the basis of cytology alone. (1)
This case also had other features typical of alimentary lymphoma. The abdominal lymphadenopathy seen here is consistent with the large percentage of cats with gastric lymphoma and lymphadenopathy in these studies. (1,2) The ascites found with Honey’s ultrasound exam was similar to that noted in 3 out of 8 cats with gastric lymphoma in one study. (2) Honey also had evidence of multicentric disease, with the kidneys being involved, confirmed with cytology, and possibly the liver and pancreas also being involved, but not confirmed.

There was equivocal evidence prior to the ultrasound exam that there was renal involvement. Her azotemia was mild and was present with a concentrated urine specific gravity. Clinically, she did appear dehydrated. The microalbuminuria was also a hint of renal involvement, but may have been secondary to the inflammation associated with the suspected pancreatitis. Radiographically, there was some irregularity of the kidneys, but without enlargement, the changes can be a normal aging change. Lymphosarcoma has been reported to cause decreased cortical echogenicity, multifocal hypoechoic areas, nodules, or masses in kidneys of dogs and cats. In cats, increased cortical echogenicity with preservation of corticomedullary distinction has been reported in nephritis and in renal lymphosarcoma, metastatic squamous cell carcinoma, and feline infectious peritonitis.(4)

Normal or decreased liver echogenicity has been reported with lymphoma in dogs and cats. Increased liver echogenicity has been reported with fatty infiltration of the liver, and with lymphosarcoma. Liver size can be increased with fatty infiltration and lymphosarcoma. (5) In this case, the liver was mildly increased in echogenicity, and enlarged radiographically. Screening cytology and clinical history pointed more toward hepatic lipidosis, but given the multicentric nature of Honey’s lymphoma, hepatic lymphoma needed to be ruled out.

The pancreatic changes seen in this case were also suspicious for lymphomatous involvement. In Penninck et al, there were two of 22 cats that had pancreatic involvement with alimentary lymphosarcoma, but these were not confirmed with necropsy, and the  ultrasonographic appearance of the pancreas was not described. (2) Nyland and Mattoon only describe focal neoplastic lesions of the pancreas, and do not mention lymphosarcoma of the pancreas. (6)

References:

• Grooters AM, Biller DS, Ward H, et al: Ultrasonographic appearance of feline alimentary lymphoma. Vet Radiol Ultrasound 1994;35:468-472.
• Penninck DG, Moore AS, Tidwell AS, et al: Ultrasonography of alimentary lymphosarcoma in the cat. Vet Radiol Ultrasound 1994;35:299-304.
• Penninck DG. Gastrointestinal Tract. In: Nyland TG, Mattoon JS, eds. Small     Animal Diagnostic Ultrasound. Saunders, Philadelphia, 2002:220-221.
• Nyland TG, et al. Urinary Tract. In: Nyland TG, Mattoon JS, eds. Small Animal Diagnostic Ultrasound. Saunders, Philadelphia, 2002:163-167.
• Nyland TG, et al. Liver. In: Nyland TG, Mattoon JS, eds. Small Animal Diagnostic Ultrasound. Saunders, Philadelphia, 2002:109-111.
• Nyland TG, et al. Pancreas. In: Nyland TG, Mattoon JS, eds. Small Animal Diagnostic Ultrasound. Saunders, Philadelphia, 2002:153-156.

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Certificate:
Dr. Doug Casey has successfully completed the IVUSS Ultrasound Certificate Program, which includes didactic training, case submission, practical exam and a written final examination.

Congratulations Doug!