A 27-year-old Arabian pony gelding presented for evaluation of weight loss, intermittent sheath oedema, persistent neutropenia and thrombocytopenia, and acute left hindlimb swelling and gait abnormality. Clinical findings included swelling, heat and sensitivity localised over the left greater trochanter, mild to moderate ventral and sheath oedema, a left hindlimb post-legged gait, and off-loading of weight from the left hindlimb at rest. Initially, neutropenia and thrombocytopenia were confirmed on bloodwork, but neutrophilia and thrombocytopenia persisted as the case progressed. Diagnostic imaging (radiography and percutaneous ultrasonography) of the left hindquarters revealed an aggressive, mixed proliferative and lytic bony lesion of the proximal left femur as well as associated muscle fibre disruption and a soft tissue mass. A percutaneous core biopsy of the lesion led to the diagnosis of osteoblastic osteosarcoma on histopathology. Pain and inflammation associated with the lesion was medically managed in the hospital with mild improvement. Additionally, palliative radiation was performed under general anaesthesia. Unfortunately, before a response to palliative radiation could be assessed, the patient was subjected to euthanasia due to development of acute neurological signs.

中文翻译：

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马股骨骨肉瘤

一头 27 岁的阿拉伯小马阉马因体重减轻、间歇性鞘膜水肿、持续性中性粒细胞减少症和血小板减少症以及急性左后肢肿胀和步态异常而就诊。临床发现包括左大转子局部肿胀、发热和敏感、轻度至中度腹侧和鞘水肿、左后肢后腿步态，以及在休息时从左后肢卸载重量。最初，血液检查证实了中性粒细胞减少症和血小板减少症，但随着病例的进展，中性粒细胞减少症和血小板减少症持续存在。左后躯的诊断成像（放射照相和经皮超声检查）显示左股骨近端有侵袭性、混合性增生性和溶解性骨病变，以及相关的肌纤维断裂和软组织肿块。病变的经皮核心活检导致组织病理学诊断为成骨细胞骨肉瘤。与病变相关的疼痛和炎症在医院进行了医学治疗，并有轻微改善。此外，姑息性放疗是在全身麻醉下进行的。不幸的是，在评估对姑息性辐射的反应之前，由于出现急性神经系统症状，患者被实施安乐死。