Periarticular histiocytic sarcoma in a French Bulldog

Abstract

Histiocytic sarcoma is a neoplasm originating from the dendritic cell lineage and presents an aggressive biological behavior and poor prognosis due to its increased metastatic rate. It can be localized, such as the articular and periarticular forms, or disseminated to several organs. Histopathological examination associated with immunohistochemistry can lead to a definitive diagnosis. The treatment of choice is surgical excision, chemotherapy, radiotherapy, or combination. Here, we report a case of periarticular histiocytic sarcoma involving the left knee joint in a female French Bulldog. The animal showed signs of lameness, a mass in the left pelvic limb, and radiographic findings suggestive of neoplasia. After cytological examination suggesting malignant mesenchymal neoplasia, the limb was amputated, and histiocytic sarcoma was diagnosed by histopathological examination and positive immunohistochemistry for CD18 and IBA1. After amputation, multimodal chemotherapy was instituted, and the animal survived for nine months from the start of chemotherapy treatment. However, the patient presented metastasis to the lungs, right pelvic limb, and superficial inguinal and popliteal lymph nodes.