A Review of Histiocytic Diseases of Dogs and Cats

Abstract

Histiocytic proliferative disorders are commonly observed in dogs and less often cats. Histiocytic disorders occur in most of the dendritic cell (DC) lineages. Canine cutaneous histiocytoma originates from Langerhans cells (LCs) indicated by expression of CD1a, CD11c/CD18, and E-cadherin. When histiocytomas occur as multiple lesions in skin with optional metastasis to lymph nodes and internal organs, the disease resembles cutaneous Langerhans cell histiocytosis of humans. Langerhans cell disorders do not occur in feline skin. Feline pulmonary LCH has been recognized as a cause of respiratory failure due to diffuse pulmonary infiltration by histiocytes, which express CD18 and E-cadherin and contain Birbeck's granules. In dogs and cats, histiocytic sarcomas (HS) arise from interstitial DCs that occur in most tissues of the body. Histiocytic sarcomas begin as localized lesions, which rapidly disseminate to many organs. Primary sites include spleen, lung, skin, brain (meninges), lymph node, bone marrow, and synovial tissues of limbs. An indolent form of localized HS, progressive histiocytosis, originates in the skin of cats. Hemophagocytic HS originates in splenic red pulp and bone marrow macrophages in dogs and cats. In dogs, histiocytes in hemophagocytic HS express CD11d/CD18, which is a leuko-integrin highly expressed by macrophages in splenic red pulp and bone marrow. Canine reactive histiocytic diseases, systemic histiocytosis (SH) and cutaneous histiocytosis, are complex inflammatory diseases with underlying immune dysregulation. The lesions are dominated by activated interstitial DCs and lymphocytes, which invade vessel walls and extend as vasocentric infiltrates in skin, lymph nodes, and internal organs (SH).

Histiocytic Sarcoma with Central Nervous System Involvement in Dogs: 19 Cases (2006–2012)

“…These breed discrepancies are intriguing and suggest the possibility of discrete mechanisms of tumorigenesis or multiple cells of origin within different organ systems that are influenced strongly by genetic factors. Aside from the splenic hemophagocytic variant, HS in dogs is believed to arise primarily from interstitial dendritic cells 1. Within the CNS, these cells are considered to be restricted to the meninges and choroid plexus 19.…”

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

“…Multinucleated giant cells are common in canine HS (15,33), especially in the disseminated form. 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.…”

“…HHS represents a distinct entity in the dog with distinctive clinicopathological features (15). Clinical and pathological findings which can indicate HHS are phagocytosing histiocytes, a diffuse pattern of tissue involvement, with preferably intra-sinusoidal (liver or lymph nodes) and intravascular spread and involvement of splenic red pulp, while encroaching on the white pulp with only sparse (T-cell) lymphocytic infiltration, extramedullary hematopoiesis, especially when the phagocytosis is prominent.…”

“…granulomatous inflammation, and reactive and systemic histiocytosis; benign tumors, i.e. histiocytoma, and malignant tumors, the histiocytic sarcomas (15). This latter group is subdivided into localized and systemic histiocytic sarcomas and the splenic hemophagocytic sarcoma (HHS).…”

Sarcoma Histiocítico Com Múltiplas Localizações Em Um Cão

“…Dentre essas proliferações podemos destacar três classificações principais, que podem ser divididas de acordo com seu comportamento biológico, obtendo assim a histiocitose reativa, histiocitoma cutâneo e o complexo sarcoma histiocítico (HENDRICK, 2017) As células de origem das proliferações histiocíticas no cão ainda não foram completamente elucidadas, porém estudos feitos com marcadores imunohistoquímicos indicaram haver uma relação dessas células com células da linhagem de células dendríticas e macrófagos (MOORE, 2014).…”