Pathologic and flow cytometric features of a case of canine ventral cervical lymphangiosarcoma.

An 11-y-old spayed female German Shepherd was presented for a second opinion of ventral cervical swelling of 3-mo duration. On examination, the dog had significant dependent ventral cervical swelling. Enlarged lymph nodes with cystic changes and severe edematous facial swelling were noted on computed tomography. Fine-needle aspiration of the ventral cervical swelling revealed yellow-tinged fluid, with a predominance of lymphoid cells noted on cytologic examination. On cervical exploratory surgery, the left mandibular lymph node was surrounded by a large fluid pocket; biopsies of the lymph node were obtained. Impression smear cytology, flow cytometry, PCR for antigen receptor gene rearrangements, and histopathology were performed on samples from the left mandibular lymph node. Impression smear cytology revealed a population of atypical discrete cells. Flow cytometry identified a population of CD34+/CD45- large cells. A tumor of endothelial origin within the medulla of the lymph node was identified by histopathology, and lymphangiosarcoma was confirmed based on prospero-related homeobox gene 1 (PROX1) immunoreactivity. Our study describes the challenges in the diagnosis of a rarely reported entity and highlights that neoplastic endothelial cells should be considered as a differential when high proportions of CD34+/CD45- cells are present in flow cytometry.

Effects of marked hypertriglyceridemia and lipid clearance techniques on canine biochemistry testing.

Triglyceride concentrations in dogs with hyperlipidemic disorders can exceed concentrations used by assay manufacturers for interference testing. High-speed centrifugation or the polar solvent LipoClear reduce triglyceride concentrations, but efficacy requires evaluation in veterinary species. We determined the effect of marked hypertriglyceridemia on canine biochemistry testing; assessed the ability of high-speed centrifugation or LipoClear to correct lipemic interferences; and determined if LipoClear introduces inaccuracy into biochemistry assays. Fifteen pooled canine serum samples were aliquoted and spiked with equal volumes of water or Intralipid [triglyceride concentration 33.9 mmol/L (3,000 mg/dL)]. Intralipid aliquots underwent lipid removal by high-speed centrifugation or LipoClear treatment, and a water-spiked aliquot underwent LipoClear treatment. Biochemistry panels were performed using a Vitros 4600 chemistry analyzer. Results were compared by paired t-test or Wilcoxon test. Total observed errors were considered clinically acceptable if below veterinary allowable total error (TEa) guidelines. Statistically significant (p ≤ 0.05) interferences were introduced by Intralipid for 15 of 15 analytes. Median observed error exceeded TEa for potassium and enzymatic carbon dioxide, neither of which were identified by the manufacturer as susceptible to lipemic interference. After centrifugation, median observed error exceeded TEa for potassium and chloride. LipoClear treatment resulted in median errors that exceeded TEa for total protein, chloride, and phosphorus. Given that severe lipemia can occur in dogs with primary or secondary hyperlipidemia, veterinary laboratories should perform their own interference testing at triglyceride concentrations relevant to their patient population and provide this information to clinicians to ensure optimal case management.