CPB 697 RESEARCH SEMINAR

DEPARTMENT OF COMPARATIVE PATHOBIOLOGY

Tricia Bisby, DVM

Graduate Student in Clinical Pathology

Department of Comparative Pathobiology

Purdue University

“A Case Of Combined Periarticular And Hemophagocytic Histiocytic Sarcoma”

Thursday, October 4, 2007

VPTH 112

3:30 pm

ABSTRACT:

A 10 year old, female spayed Rottweiler dog was being treated for T cell lymphoma. A mass on the flexor surface of the left elbow was noted during a recheck visit and cytologically diagnosed as lymphocytic-macrophagic inflammation. The dog later presented for evaluation of lethargy and anorexia. CBC findings included a marked non-regenerative anemia (HCT 14.2%), marked thrombocytopenia (4840/ul), and a regenerative left shift with evidence of toxicity. Serum chemistry revealed hypoalbuminemia as well as elevations in ALT, ALP, GGT, and total bilirubin. A bone marrow aspirate was markedly cellular with 20-25 micron round cells, suggestive of histiocytes, comprising approximately 30% of all cells. Marked erythrophagia and leukophagia were observed. The cells were strongly positive for BLA36 and moderately positive for CD11d on immunocytochemistry. The cells were negative for CD3, CD79a, TCRγδ, CD1c, CD11c, and CD11b. Despite treatment, the dog rapidly deteriorated and died. Necropsy and histopathology demonstrated neoplastic histiocytes in the spleen, bone marrow, liver, all peripheral lymph nodes, and the previously mentioned elbow mass. Neoplastic cells comprising the elbow mass were positive for CD18, BLA36, and CD11c. Based on these results a diagnosis of periarticular histiocytic sarcoma and disseminated hemophagocytic histiocytic sarcoma was made. This case likely represents a rare presentation of mixed histiocytic sarcoma with both dendritic (elbow mass) and macrophagic (hematopoietic tissues) origins, and is the first case to demonstrate the labeling of histiocytes with BLA36 in domestic species.