Sep 012013
 

Enlarged jejunal lymph node in a red-necked wallaby

 

Case information

A 1.5-year-old, castrated, male red-necked wallaby presented for a one-week history of inappetance, depression, and diarrhea. The primary veterinarian had administered penicillin to no effect. The wallaby was housed in a fenced, outdoor enclosure with limited exposure to wild animals. The owners had an indoor-only cat; while the wallaby was raised indoors throughout the fall and winter, it did not have direct contact with the cat. The wallaby was up to date on rabies and tetanus vaccinations, had no exposure to toxins, no known ingestion of foreign material, and no changes in diet or husbandry.

On presentation, a firm, tubular structure was palpated in the dorsal abdomen. The rest of the physical examination was within normal limits. Abdominal radiographs revealed equivocally gas distended intestines. Abdominal ultrasound revealed fluid-filled intestines, normal gastrointestinal motility, a small amount of free abdominal fluid, and an enlarged jejunal lymph node, which corresponded to the mass detected on palpation. A hemogram revealed a leukocyte count of 4.4 x 103 cells/μL (International Species Information System; mean ± SD; 5.9 ± 2.6 x 103/μL), consisting of 2.5 x 103 neutrophils/μL (2.0 ± 1.2 x 103/μL), 0.1 x 103 band neutrophils/uL (1.0 ± 2.0 x 103/μL) and 1.8 x 103 lymphocytes/μL (3.3 ± 1.8 x 103/μL). There was moderate toxic change in neutrophils and a few reactive lymphocytes were seen. The platelet count was 111 x 103/μL (183 ± 110 x 103/μL). Pertinent chemistry results are shown in the table below:

Test
Result
ISIS
Sodium (mEq/L)
130
140 ± 5
Potassium (mEq/L)
2.2
4.9 ± 1.3
Chloride (mEq/L)
85
97±5
Urea nitrogen (mg/dL)
55
25 ± 6
Creatinine (mg/dL)
1.5
1.1 ± 0.3
Albumin (g/dL)
2.3
4.2 ± 0.6
Globulin (g/dL)
3.4
2.4 ± 0.9
Glucose (mg/dL)
218
96 ± 27
ALT (U/L)
491
48 ± 27
AST (U/L)
898
95 ± 92
ALP (U/L)
1048
1062 ± 891
GGT (U/L)
27
40 ± 24
Total bilirubin (mg/dL)
0.3
0.2 ± 0.2
Creatine kinase (U/L)
25039
1221 ± 902

 

An aspirate was taken from the enlarged jejunal lymph node. View the photomicrographs then answer the questions below.

  • What is your diagnosis based on the cytologic findings of the lymph node aspirate?
  • How does this result explain the changes in the hemogram and chemistry profile?
  • What additional tests are indicated?

Figure 1: Jejunal lymph node 200x

Figure 1: Jejunal lymph node aspirate (200x, Wright’s stain)

Figure 2a: Jejunal lymph aspirate

Figure 2a: Jejunal lymph node aspirate (1000x, Wright’s stain)

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