Dr Shasta Lynch
BVSc(hons) MANZCVS(SAM) DipECVIM-CA(Oncology) MRCVS
RCVS, Australian and European Veterinary Specialist in Oncology
Do you remember Ella, the lumpy Lakeland Terrier that presented with a 4 week history of polyuria, polydipsia and reduced appetite?
In Part 1 of this case study, we defined Ella’s problem list as:
- Peripheral lymphadenopathy
- Azotaemia
- Ionised hypercalcemia
To recap: the Azotaemia was most likely related to renal causes in this patient. This may be due to ionised hypercalcemia and/or underlying renal disease.
The Ionised hypercalcemia together with the peripheral lymphadenopathy, certainly made lymphoma a strong differential.
However, the cytology of the peripheral lymph nodes was not consistent with lymphoma and was instead suggestive of reactive hyperplasia and extra-medullary hematopoiesis.
What would you do now to investigate this case further?
You could remove a lymph node for histopathology or perform flow cytometry on the lymph nodes.
You could sample a different lymph node with FNA.
You could perform PTH/PTH-rp to investigate hypercalcemia further.
Should any treatment be administered while you investigate this patient further?
0.9%NaCl is the best fluid to administer to reduce calcium levels and it should be administered at a sufficient rate to rehydrate and cause diuresis e.g. 3 x maintenance. Frusemide can be added once hydrated if necessary.
So what further investigations were advised by the Oncology Specialist?
If you mentioned any of the above options for investigating further, they are all correct!
In Ella’s case it was elected to perform thoracic radiographs and abdominal ultrasound with fine needle aspirates of the liver, spleen and enlarged sternal lymph node.
Left lateral thoracic radiograph. You can see the enlarged sternal lymph node marked with a black ‘x’. There was also an interstitial-alveolar pattern more obvious in the cranioventral lung field which may represent neoplastic infiltrate or bronchopneumonia.
The cytology report from the sternal lymph node provided the diagnosis:
Description-
The best preparation (from a total of 8) had low to moderate numbers of intact cells, low numbers of erythrocytes and abundant lysed cells in a lightly basophilic background. Intact cells were dominated by medium lymphocytes (>80%) with round to rarely indented nuclei, finely granular chromatin, commonly with multiple small nucleoli, and small to moderate amount of lightly to moderately basophilic cytoplasm with occasional punctate vacuoles.
Occasional to low numbers of mitotic figures were seen.
Small lymphocytes were present but in very low numbers (<10%).
Occasional plasma cells and mildly increased numbers of neutrophils were also found. Microorganisms were not seen.
Other preparations were highly diluted with blood.
Conclusion- Consistent with lymphoma
PTH-rp results subsequently were received and were elevated consistent with hypercalcemia of malignancy.
We then performed flow cytometry on the sternal lymph node to determine the immunophenotype. The results were as follows:
Aliquots of the cell suspension were stained with a panel of antibodies, including markers of lymphoid, granulocytic and monocytic cells and then analysed by flow cytometry. The atypical cells were identified on the basis of their forward scatter (determined by cell size) and side scatter (determined by cell complexity) and the staining profile of these atypical cells was determined. They stained with the following antibodies.
| Antibody | Result | Significance |
| CD3 | Positive | T cells |
| CD21 | Negative | B cells (only if relatively mature) |
What treatment protocol would be most appropriate for Ella?
You may already have been suspicious that Ella had T rather than B cell lymphoma because T cell lymphoma is the most common immunophenotype associated with hypercalcemia.
The author’s preference in these patients is for a modified LOPP protocol with continued saline diuresis until calcium levels return to normal and renal function is adequate.
Ella received a modified LOPP protocol. Another alternative would have been a lomustine/prednisolone protocol although this is probably less effective. Doxorubicin containing protocols are also an option however only about 50% of dogs with T cell lymphoma will respond.
The LOPP protocol consisted of vincristine day 1, lomustine day 7, procarbazine day 1-14, prednisolone, 21day cycle.
ALT was checked before each lomustine treatment and haematology before each lomustine and vincristine treatment and one week after the first lomustine treatment at the expected neutrophil nadir.
Follow-up
Ella relapsed with right popliteal lymphadenopathy and lymphoma on cytology 125 days after diagnosis. She was receiving the LOPP protocol at the time of relapse and so was resistant to these drugs. Various rescue protocols were attempted with short-lived responses for each. The owner elected euthanasia due to progressive disease, lethargy and inappetence 294 days after initial diagnosis.