Prognosis for histiocytic sarcoma (HS) in Bernese Mountain Dogs (BMDs) is poor regardless of treatment form, with a median survival of 170 days across all dogs with HS. Subgroup analysis identifies disseminated HS and palliative treatment as statistically significant negative prognostic factors for survival. Veterinary and…

Staging is based on extent of disease at diagnosis, with HS classified as localized (confined to a single organ or local lymph nodes) or disseminated (widespread multi-organ involvement). Disseminated HS is recorded significantly more frequently in BMDs (60.8%) than in Flat-Coated Retrievers (39.4%), making disseminated disease the predominant presentation in this breed. Veterinary Scie… Common primary sites include the spleen, lymph nodes, lungs, bone marrow, CNS, skin, subcutis, and periarticular tissues; secondary dissemination frequently involves the liver, lungs, and hilar lymph nodes. Journal of the… If an internal organ is affected, disseminated disease is often already present at the time of diagnosis. Journal of the…

The staging workup should include thoracic imaging, abdominal imaging, and evaluation of bone marrow, given the typical dissemination pattern. Computed tomography detects lesions in pulmonary tissue, thoracic lymph nodes, spleen, kidney, and bone with accuracy comparable to autopsy, though hepatic nodules are difficult to detect with standard CT protocols — CT identified hepatic lesions in 2 of 7 cases confirmed at autopsy. BMC Veterinary… Cytology and histopathology with immunophenotyping are required to confirm histiocytic lineage, as HS can resemble other round cell tumors, anaplastic carcinomas, and sarcomas on morphology alone. Journal of the… CD18 positivity and pancytokeratin negativity confirm histiocytic origin. Journal of Vete…+1

Hematologic staging findings in BMDs include leukocytosis and thrombocytopenia, which occur significantly more often in BMDs than in Flat-Coated Retrievers even after correcting for HS type. Hypercalcemia was identified in 15 BMDs with HS and in none of the Flat-Coated Retrievers evaluated. Veterinary Scie… The hemophagocytic form of HS — arising from splenic red pulp and bone marrow macrophages rather than dendritic cells — presents with a distinct clinical syndrome of regenerative anemia, thrombocytopenia, hypoalbuminemia, hypocholesterolemia, and splenomegaly, and has rapid clinical progression. Journal of the…

Concurrent corticosteroid use is a statistically significant negative prognostic factor and should be avoided. Palliative treatment and disseminated disease at presentation are the other two independently confirmed negative prognostic variables. Veterinary and… Early detection and surgical removal of localized lesions offers a better prognosis; periarticular HS carries a better prognosis than nonperiarticular HS. Journal of the…+1

HS is the dominant cause of death in BMDs, with neoplasia accounting for 28.1–55.1% of deaths in this breed compared to 14.5–16.5% in the general dog population, and HS specifically is described as highly aggressive with a very poor prognosis. BMC Veterinary… A familial polygenic inheritance pattern has been proposed, and blood biomarker screening for early detection is under investigation in BMDs. Journal of the…+1

Would you like to review the chemotherapy options and response rates for disseminated HS in BMDs?