Histiocytic sarcomas in flat‐coated retrievers: a summary of 37 cases (November 1998–March 2005)

Abstract

Thirty-seven cases of histiocytic-like sarcomas (HLSs) in flat-coated retriever dogs were evaluated retrospectively. This tumour accounted for 36% of the malignant tumours seen in this breed during the study period. The median age at presentation was 8.2 years. Thirty-four dogs presented with a swelling or mass in a muscle group or surrounding a joint. The remaining three presented for rib (1), cutaneous (1) or primary splenic origin (1). A high rate of metastasis to local lymph nodes (45%), thorax (20%) and abdominal organs (20% confirmed) was seen. Overall metastastic rate by the time of death was 70%. The median survival for all dogs was 123 days. The most significant prognostic indicator was presence of distant metastasis at the time of diagnosis with median survival of 68 or 200 days, with or without metastasis, respectively. Chemotherapy and radiation therapy significantly improved survival. Dogs given chemotherapy survived a median of 185 versus 34 days for dogs that were not (P = 0.0008). Dogs treated with radiation survived a median of 182 versus 60 days for those that were not (P = 0.0282). Dogs receiving only palliative therapy survived a median of 17 versus 167 days in dogs receiving any kind of radiation, chemotherapy, surgery or combinations. A set protocol of radiation and CCNU (RTCCNU) induced minimal toxicity and provided a median survival of 208 versus 68 days for all other dogs. While this tumour carries a poor long-term prognosis in flat-coated retrievers, it is reasonable to treat these dogs for palliation of signs and extension of life.

Evaluation and comparison of outcomes in dogs with periarticular and nonperiarticular histiocytic sarcoma

“…2 Despite reported metastatic rates of 70% to 91%, treatment consisting of surgery, radiation, chemotherapy, or a combination of these appears to improve outcome in dogs with HS. 3,4 In a recent study 7 of 59 dogs with gross or disseminated disease, 54% of dogs that lived longer than 7 days following the first treatment with lomustine achieved either a partial or complete response, and the patients that responded experienced an MST of 5.5 months. In a series 4 of 37 Flat-Coated Retrievers with LHS, the presence of distant metastasis at diagnosis was a strong negative predictor of survival time.…”

“…3,4 In a recent study 7 of 59 dogs with gross or disseminated disease, 54% of dogs that lived longer than 7 days following the first treatment with lomustine achieved either a partial or complete response, and the patients that responded experienced an MST of 5.5 months. In a series 4 of 37 Flat-Coated Retrievers with LHS, the presence of distant metastasis at diagnosis was a strong negative predictor of survival time. However, any form of treatment beyond pain management or corticosteroids significantly improved outcome regardless of metastatic status.…”

“…3,4 In a recent study 7 of 59 dogs with gross or disseminated disease, 54% of dogs that lived longer than 7 days following the first treatment with lomustine achieved either a partial or complete response, and…”

“…2 Localized HS appears to arise from a single site, typically Evaluation and comparison of outcomes in dogs with periarticular and nonperiarticular histiocytic sarcoma involving the lung, skin, subcutaneous tissues, bones, or joints. [2][3][4][5][6] Disseminated HS involves multiple organ systems, which could indicate metastasis and progression of the localized form. Alternatively, disseminated HS may be a primary multicentric disease, in which tumors arise simultaneously in multiple locations.…”

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

“…This has been reported before in canine HS (1,6,7,28,(33)(34)(35)(36)(37)(38)(39) and is also often seen in human HS, sometimes simultaneously with spindle cells (40,41). In addition, extramedullary hematopoiesis was seen more often in BMD than in FCR.…”