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EQUINE VETERINARY EDUCATION / AE / OCTOBER 2014
Case Report
Severe hindlimb lameness and pathological femur fracture in a horse secondary to haemangiosarcoma
A. T. Mahne*,H.J. Marais,L.M. Rubio-Martinez and J. H. Williams† Department of Companion Animal Clinical Studies, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa; and †Department of Pathology, Faculty of Veterinary Science, University of Pretoria, Onderstepoort, South Africa. *Corresponding author email:
arnold.mahne@
up.ac.za
Keywords: horse; haemangiosarcoma; femur; lameness; fracture; histopathology
Summary An 18-year-oldWarmblood stallion was presented for an acute onset nonweightbearing right hindlimb lameness following a mild lameness of 2 weeks’ duration. Severe swelling was present in the right femoral area. Despite extensive diagnostic procedures, no definitive diagnosis could be made. Packed red cell volume was persistently low. The horse improved with supportive treatment and was discharged at the owner’s request. The horse presented 4 days later for bleeding from a previously made incision on the lateral femoral area. Due to deterioration of his condition, the stallion was subjected to euthanasia. Diagnosis of disseminated haemangiosarcoma, affecting primarily the hindlimb musculature and leading to pathological fracture of the femur was made at necropsy and subsequent histopathology.
Introduction
Haemangiosarcoma is a malignant tumour of vascular endothelial origin (Cottle et al. 2008) that rarely affects horses: it occurred in 0.01% (Braun 2007) and 0.05% (Johns et al. 2005) of cases admitted to equine hospitals in 2 large retrospective studies. Two different age-related manifestations of haemangiosarcoma have been reported in horses (Johns et al. 2005). Younger horses often present with cutaneous masses, leg swelling or joint effusion and have a variable prognosis for survival (Johns et al. 2005), whereas middle aged and older horses typically have multiple organ involvement and show rapid clinical deterioration. In the latter disseminated manifestation the respiratory and musculoskeletal systems are most commonly affected (Southwood et al. 2000). This disseminated form poses a diagnostic challenge to the clinician and a diagnosis is often only reached after a detailed post mortem examination. Lameness and muscular or subcutaneous swelling
accounted for up to 36% of the primary complaints in 35 cases with disseminated haemangiosarcoma (Southwood et al. 2000). Other isolated cases of haemangiosarcoma leading to lameness have also been described (Pelt et al. 1972; Waugh et al. 1977; Kiupel et al. 2000; Knottenbelt and Clegg 2004; Pille et al. 2004; Cottle et al. 2008). This report describes the clinical, diagnostic and post
mortem findings of a primary periosteal or skeletal muscular haemangiosarcoma causing severe hindlimb lameness and leading to pathological femur fracture in a horse. To the authors’ knowledge this is the first equine report of this kind.
© 2012 EVJ Ltd Case details
History An 18-year-old European Warmblood breeding stallion was referred to Onderstepoort Veterinary Academic Hospital (OVAH) for evaluation of severe right hindlimb lameness. The stallion had a history of mild right hindlimb lameness of 2 weeks’ duration, which acutely progressed to nonweightbearing. The horse had been active as a breeding stallion for 2 months prior to the onset of lameness. The referring veterinarian had performed physical and radiographic examinations of the distal limb up to the tarsus with reported absence of significant findings and the horse was referred for a suspected pelvic fracture. The horse had received phenylbutazone (8.8 mg/kg bwt i.v.) before referral.
Clinical findings The stallion was in good overall body condition. There was atrophy of the right gluteal muscles and severe right hindlimb swelling extending from the proximal femoral area to the distal aspect of the tarsus (Fig 1). The stallion had a dull demeanour, rectal temperature of 37.5°C, tachycardia (80 beats/min), tachypnoea (40 breaths/min), pale pink mucous membranes and showed sweating. Grade 5/5 lameness (Anon 1991) was present in the right hindlimb. The right metatarso-phalangeal joint was held in flexion resulting in weightbearing on the dorsum of the digit. No abnormalities were detected on rectal examination. Evaluation of a peripheral blood smear was unremarkable with blood packed cell volume (PCV) 34% (reference range [rr] 24–44%) and total serum protein (TSP) 64 g/l (rr 66–83 g/l).
Diagnostic imaging The horse was sedated with romifidine (Sedivet, 0.04 mg/kg bwt i.v.)1 and ultrasonographic examination of the right hemi-pelvis, right femur and surrounding soft tissues was performed. This revealed severe soft tissue swelling and multiple irregular, poorly marginated hyper- to hypoechoic areas at the caudo-lateral aspect of the mid-femur. To obtain proximal femur and pelvis radiographs
the horse was sedated with butorphanol (Torbugesic, 0.02 mg/kg bwt i.v.)2 and romifidine (0.08 mg/kg bwt i.v.) and induced into general anaesthesia with ketamine (Ketamine-Fresenius, 2 mg/kg bwt i.v.)3. Anaesthesia was maintained with halothane (Halothane M and B)4, oxygen inhalation and a constant rate infusion of ketamine (2 mg/kg bwt/h i.v.) and metdetomidine (Domitor, 1 mg/kg bwt/h i.v.)5.
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