Mast cell and plasma cell collision tumor in the spleen of a dog.

A 9-year-old spayed female English Mastiff was referred for outpatient ultrasound due to a 3-week history of weight loss, vomiting, and decreased appetite. Abdominal ultrasound showed multiple splenic masses of varying sizes and serum chemistry panel showed hyperglobulinemia. Cytologic examination of fine-needle aspirates of the splenic masses indicated a mast cell and plasma cell collision tumor. Results of serum and urine protein electrophoresis and immunofixation indicated the plasma cell neoplasia was producing IgA immunoglobulins.

Characterization of aminoaciduria and hypoaminoacidemia in dogs with hepatocutaneous syndrome.

OBJECTIVE To characterize aminoaciduria and plasma amino acid concentrations in dogs with hepatocutaneous syndrome (HCS). ANIMALS 20 client-owned dogs of various breeds and ages. PROCEDURES HCS was definitively diagnosed on the basis of liver biopsy specimens (n = 12), gross and histologic appearance of skin lesions (4), and examination of skin and liver biopsy specimens (2) and presumptively diagnosed on the basis of cutaneous lesions with compatible clinicopathologic and hepatic ultrasonographic (honeycomb or Swiss cheese pattern) findings (2). Amino acid concentrations in heparinized plasma and urine (samples obtained within 8 hours of each other) were measured by use of ion exchange chromatography. Urine creatinine concentration was used to normalize urine amino acid concentrations. Plasma amino acid values were compared relative to mean reference values; urine-corrected amino acid values were compared relative to maximal reference values. RESULTS All dogs had generalized hypoaminoacidemia, with numerous amino acid concentrations < 50% of mean reference values. The most consistent and severe abnormalities involved glutamine, proline, cysteine, and hydroxyproline, and all dogs had marked lysinuria. Urine amino acids exceeding maximum reference values (value > 1.0) included lysine, 1-methylhistidine, and proline. CONCLUSIONS AND CLINICAL RELEVANCE Hypoaminoacidemia in dogs with HCS prominently involved amino acids associated with the urea cycle and synthesis of glutathione and collagen. Marked lysinuria and prolinuria implicated dysfunction of specific amino acid transporters and wasting of amino acids essential for collagen synthesis. These findings may provide a means for tailoring nutritional support and for facilitating HCS diagnosis.