Dendritic cell leukemia in a Golden Retriever

Abstract

An 8-year-old castrated male Golden Retriever was evaluated for decreased appetite, lethargy, and labored breathing of 1-week duration. Bilateral pulmonary infiltrates, hepatomegaly, and splenomegaly were present. Results of a CBC revealed marked leukocytosis (62,600/microL; reference interval 4000-15,500/microL) and large numbers of atypical cells (30,700/microL) with abundant cytoplasm. There was no concurrent anemia, neutropenia, or thrombocytopenia. Morphology of the atypical cells was most consistent with a histiocytic origin. Similar cells were identified in bone marrow aspirates, and were morphologically suggestive of the macrophage variant of disseminated histiocytic sarcoma. However, flow cytometry of the abnormal circulating cells revealed CD1c, CD11c, and major histocompatibility complex (MHC) Class II expression without expression of CD11d or lymphoid markers, consistent with myeloid dendritic antigen-presenting cells. At necropsy, the splenic architecture was effaced by neoplastic histiocytes that were also infiltrating lung, liver, an abdominal lymph node, myocardium, an bone marrow. Immunohistochemistry of the splenic neoplastic cells confirmed dendritic cell origin (CD1c+, CD11c+, MHC II+, no expression of CD11d and lymphoid markers). To the authors' knowledge, this is the first report of canine dendritic cell leukemia-in this instance accompanied by marked tissue infiltration.

Multifocal cutaneous histiocytic sarcoma in a young dog and review of histiocytic cell immunophenotyping

“…Discrete pleomorphic mononuclear and multinucleated cells with prominent features of malignancy typical of HS also were not observed . Cytologically, the cells did resemble those in bone marrow from a dog with dendritic cell leukemia …”

A Review of Histiocytic Diseases of Dogs and Cats

“…There have been 2 reports of DC leukemia in dogs; in both instances, large numbers of atypical histiocytes were observed in peripheral blood (30,000 -60,000 per ml). 6,68 In both dogs, the DC lineage (CD1þ CD11cþ CD11d-MHCIIþ) was confirmed by extensive immunophenotyping of cell smears or by flow cytometry. Diffuse infiltration of affected organs (bone marrow, spleen, lung, and liver) without mass formation was characteristic of a leukemic infiltrate.…”

“…Diffuse infiltration of affected organs (bone marrow, spleen, lung, and liver) without mass formation was characteristic of a leukemic infiltrate. 6 This is also the pattern of infiltration exhibited by hemophagocytic HS. However, this latter disease does not involve peripheral blood and is associated with a responsive extravascular hemolytic anemia and marked erythrophagocytosis by neoplastic histiocytes, which express CD11d.…”

“…51 CD11d was not expressed by neoplastic histiocytes in either dog. 6,68 Feline Progressive Histiocytosis. Feline progressive histiocytosis (FPH) is a disease of middle-aged to older cats (age range, 7-17 years).…”

Morphological Distinction of Histiocytic Sarcoma from Other Tumor Types in Bernese Mountain Dogs and Flatcoated Retrievers

“…In humans, multinucleated giant cells are less frequently present in HS (43), as well as in IDCS (13), FDCS (44) and indeterminate DCS (45), which may imply a more malignant nature of HS in canines. The characteristic kidney-shaped nuclei have also been reported before in canine HS (33,39,46) and in human HS (47) and IDCS (14). Indentations of the nucleus have been reported in the canine literature (1,7,24,26,28) as well as in human HS (41) and IDCS (48), and a combination of indentations, grooves or folds in human HS (43,49), IDCS (14) and LCH (50).…”