Concurrent chronic lymphocytic leukemia and primary hyperparathyroidism in a mule.
Authors: Townsend Kile S, Johnson Philip J, Donnelly Lindsay L, LaCarrubba Alison M, Lattimer James C, Havis Brett, Springer Nora L, Kim Dae Y
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary A 26-year-old mule presenting with seven months of progressive weight loss and reduced appetite presented a diagnostic challenge when laboratory workup revealed concurrent severe hypercalcaemia, marked hypophosphatemia, elevated parathyroid hormone, and significant lymphocytosis. Flow cytometry and PCR for antigen receptor rearrangement (PARR) confirmed a B-cell lymphoproliferative disorder consistent with chronic lymphocytic leukemia, whilst the markedly elevated PTH and calcium levels indicated primary hyperparathyroidism—a pairing not previously documented together in equine patients. Although a sestamibi scan failed to localise parathyroid tissue, the biochemical evidence for both conditions was compelling, suggesting that in older equids presenting with wasting and hypercalcaemia, clinicians should consider that multiple concurrent endocrine and haematopoietic conditions may be contributing to the clinical picture. The clinical significance lies in recognising that either condition alone can explain weight loss and calcium dysregulation, but their concurrent presentation complicates treatment planning and prognostication, requiring more nuanced diagnostic interpretation than might be expected from a single disease process.
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Practical Takeaways
- •In aged equids presenting with chronic weight loss and hypercalcemia, consider screening for both parathyroid and hematologic malignancies, as these conditions may occur concurrently.
- •Marked hypercalcemia with elevated PTH in a horse or mule warrants comprehensive blood work including flow cytometry to rule out concurrent lymphoproliferative disorders.
- •Sestimibi scans may be nondiagnostic for parathyroid pathology in equids; diagnosis often relies on laboratory abnormalities and advanced hematologic testing.
Key Findings
- •A 26-year-old mule presented with concurrent chronic lymphocytic leukemia and primary hyperparathyroidism, conditions not previously described together in equids.
- •Laboratory findings showed severe total hypercalcemia, marked hypophosphatemia, markedly increased parathyroid hormone concentration, and marked lymphocytosis.
- •Flow cytometry and PCR for antigen receptor rearrangement confirmed B cell lymphoproliferative disorder consistent with CLL.
- •The concurrent presence of these two conditions complicated clinical interpretation of weight loss and hypercalcemia in an aged equid.