Clinical Outcomes in Dogs with Localized Splenic Histiocytic Sarcoma

Sandra Bechtel, DVM, DACVIM, University of Florida

ArticleLast Updated November 20212 min read
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In the Literature

Latifi M, Tuohy JL, Coutermarsh-Ott SL, Klahn SL, Leeper H, Dervisis N. Clinical outcomes in dogs with localized splenic histiocytic sarcoma treated with splenectomy with or without adjuvant chemotherapy. J Vet Intern Med. 2020;34(6):2645-2650.


The Research …

Histiocytic sarcoma in dogs can be localized, disseminated, or hemophagocytic; these subtypes and the location of the localized histiocytic sarcoma affect treatment recommendations and prognosis. For example, localized treatment for periarticular, cutaneous, and pulmonary histiocytic sarcoma can lead to prolonged survival times (ie, one year or longer).1-3 Localized histiocytic sarcoma of the spleen in dogs is uncommon, and prognosis after splenectomy with or without chemotherapy has not been clearly characterized. 

The objectives of this retrospective, multi-institutional study were to describe the prognostic clinical factors and patient outcomes of splenectomy with and without adjuvant chemotherapy in dogs diagnosed with localized splenic histiocytic sarcoma. Fourteen dogs were identified for inclusion, and all dogs had splenectomy performed. Two dogs had lymph node metastasis at the time of surgery, and 12 dogs were administered adjuvant chemotherapy that included either lomustine (n = 10) or alternating lomustine and doxorubicin (n = 2). Five dogs developed suspected or confirmed metastatic disease following splenectomy. 

Overall median survival time was 427 days. The median progression-free interval was 205 days. None of the studied clinical variables were predictive of survival; however, this study’s sample size was small. The role of chemotherapy in survival could not be determined, as only 2 dogs did not receive chemotherapy.  

Although this study was retrospective (resulting in variable treatment, staging, and follow-up protocols), results suggest that localized histiocytic sarcoma of the spleen may have a favorable outcome following splenectomy and chemotherapy.


… The Takeaways

Key pearls to put into practice:

  • Histiocytic sarcoma in dogs can be disseminated or localized. The most common sites of localized histiocytic sarcoma are periarticular and pulmonary and have a favorable prognosis as compared with disseminated histiocytic sarcoma.

  • Localized splenic histiocytic sarcoma is typically a component of disseminated histiocytic sarcoma. Full staging is recommended prior to considering splenectomy and should include 3-view thoracic radiography, abdominal ultrasonography, and fine-needle aspiration and cytology of any suspicious lesions.

  • Localized splenic histiocytic sarcoma is uncommon. Splenectomy followed by chemotherapy, however, may provide a median survival time of one year.