Sarcoid Tumor in a Horse

A middle-aged gelding presented to PHD Veterinary services for the removal of a large tumor from the base of the right ear (Figures 1 and 2). Two years prior, a smaller tumor was surgically removed from the same ear. The histological report was consistent with a sarcoid tumor. At the time of the original surgery, several sarcoids were removed from different areas including the pectoral region and groin area. The recurring sarcoids were treated with intra-lesional chemotherapy, cryotherapy, topical medications and systemic herbal remedies. At presentation, a large, lobulated tumor was "hanging" from the base of the right ear. There was mild hemorrhage and evidence of moderate necrosis of the tumor. The gelding was resistant to manipulation of the tumor however gentle palpation of the ear noted that the tumor was NOT attached to the cartilage portion of the ear but only the skin and immediate subcutaneous tissues.

Figure 1

Figure 2

The gelding was rendered unconscious via injectable anesthetics and the tumor was removed through a large incision (Figure 3 and 4). Moderate hemorrhage was encountered confirming that the tumor was highly vascular. The incision was partially closed with sutures and the horse was recovered from anesthesia. Examination of the tumor after removal noted it consisted of 3 individual masses and weighed more than one pound (Figure 5).

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This case represents an extreme example of recurrent sarcoids in a horse. Per the owner, the previous management of the sarcoids were initially effective however in time the tumors returned. The removal or de-bulking of the ear-based tumor will most likely not be sufficient in keeping the sarcoid tumor from removal. Aggressive therapy involving intra-lesional chemotherapy agents and cryotherapy will be employed to keep these tumors from continuing the develop!!

Figure 6

 Fast forward 6 weeks and the surgical wound is in the process of healing nicely (Figure 6), however there are several small sarcoids along the tip of the ear and also within the surgical site that are inflamed and beginning to grow. Follow-up treatment included the injection of cisplatin directly into the small sarcoids. Unlike the initial procedure which was done under anesthesia, the cisplatin injection was performed with sedation and a local "block" of the ear. Two weeks after the cisplatin injection, the small sarcoids along the tip of the ear are shrinking however the sarcoids within the surgical site remain inflamed  (Figure 7).

Figure 7

 Hence, the small sarcoids were treated with cryotherapy and the picture in Figure 8 was approximately 2 weeks post cryotherapy. The initial surgical site is a scar and all of the small sarcoids are regressing nicely. This horse will be monitored very carefully to make sure that any new sarcoid growth is treated aggressively!! This case represents an excellent example of the need for early, aggressive and multi-drug treatment of sarcoids in horses.

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Atrial Fibrillation in a Horse

 An 18 year-old gelding presented for a pre-lease exam. The horse was sound and displayed no clinical abnormalities. However, when the heart was auscultated the heart rhythm was abnormal. Normally, a horse's heart sounds like two distinct sounds, otherwise known as the "lub-dub". These two sounds correspond to the opening and closing of specific heart valves during contraction and filling of the heart's chambers . There are actually 4 heart sounds but typically we only describe the "lub-dub". In a normal horse, the number of lub-dubs that are counted in a minutes range between 28-40 lub-dubs or beats per minute and they should be equally spaced in time. The electrocardiogram (EKG) in Figure 1 is that of a normal horse. The red arrows correspond to the contraction of the ventricles and the green arrows correspond to the contraction of the atrial. Normally, the atria contract first followed by the contraction of the ventricle. The blue arrow corresponds to the time between ventricle contractions which should equal the heart rate or number of lub-dubs auscultated in a period of time. Notice that the blue arrows are equal in length between heart beats AND that there is one green arrow for every red arrow!!

Figure 1

The lub-dubs for this particular horse were irregular and there was no predictability of their irregularity hence the heart rhythm was described as "irregularly, irregular". This type of heart arrhythmia is consistent with a condition known as atrial fibrillation. In Figures 2 and 3 notice that the blue arrows which correspond to the time between heart beats vary significantly. Equally important, there appears to be many more green arrows (Figure 3) than red arrows. This would suggest that the atria is contracting more often than the ventricles, hence the term atrial fibrillation!!

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 Atrial fibrillation in horses is not uncommon and young horses with this condition are often asymptomatic. Thoroughbreds are diagnosed most often and when it is diagnosed in younger horses, the cause for the arrhythmia is often not determined. However, in older horses underlying heart disease is often associated with atrial fibrillation.  The most common clinical complaint would be exercise intolerance and decline in performance. In addition, an elevated resting heart rate may be indicative of early congestive heart failure as well as persistently distended jugular veins (Figure 4). Diagnosis of atrial fibrillation requires an EKG and a cardiac ultrasound is recommended to determine if there is underlying heart disease. Often a 24 hr halter monitor (Figure 5) may be used to better describe the horse's 24 hr cardiac cycle. There are several methods available to try and "convert" a horse with atrial fibrillation. However, it is important to first determine that cardiac disease nor electrolyte disturbances are the root of the problem. The methods include various medications and electrical cardi-conversion.  Prognosis for horses with atrial fibrillation depends on whether the horse has underlying cardiac disease. In the case of cardiac disease, the prognosis is poor; however, in young horses with idiopathic atrial fibrillation, the prognosis can be good for full return to work as a sport horse!! This case re-inforces the need for a solid physical exam on a regular basis to make sure this type of disease does not go undetected!!
  

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Superficial Flexor Tendonitis in a Horse

A middle-aged gelding presented to PHD veterinary services for tendonitis of the superficial flexor tendon (SDF). The tendonitis was a result of an tendon-sheath penetrating injury and was associated with a severe tendon sheath infection. The tendon sheath infection was treated aggressively and effectively by an equine surgeon. An ultrasound exam was performed along the plantar aspect of the hind fetlock and a large, core-like lesion was identified (Figure 1, black area within red circle). The lesion consisted of disrupted tendon fiber and edema. Several options were considered to help the "healing process" involving the SDF tendonitis. These included extra corporeal shock wave treatment, platelet rich plasma (PRP) injection, stem cell injection, and/or concentrated bone marrow injection. The decision was made to treat the lesion by injecting a mixture of concentrated bone marrow mixed with PRP product. The bone marrow was collected from the horse's sternum and concentrated on site (Figure2). In addtion, a blood sample was collected from the horse and PRP was harvested on site. The PRP was mixed with the concentrated bone marrow and then injected into the lesion via ultra-sound guided technique.

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In addition to the PRP+bone marrow injection, the horse was fitted with a corrective shoe that provided significant heel extension (Figure 3 and 4). This type of shoe is also known as a "fish tail" show and will reduce the "load" across the fetlock joint by supporting the lower limb. Horses recovering from tendon sheath infections and SDF tendonitis tend to avoid fully loading the back of the foot which may result in lower limb contracture. The fish tail shoe allows the horse to fully load the foot in a more comfortable fashion. The horse was walked daily and otherwise kept in stall confinement. In addition, the leg was treated daily with cold compresses.

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Approximately 30 days after the PRP+bone marrow injection, the horse's limb was re-ultrasounded. There has been significant "filling in" of the lesion (Figure 5). Although the area that was the lesion (red circle) remains identifiable, there has been a significant improvement in tendon fiber alignment and the edema (black) has nearly completely resolved! Although this represents a tremendous amount of improvement in just 30 days, there remains a significant period of rehabilitation before the ultimate out come of this case can be reported.  This case provides an example of a regenerative therapy that combines PRP and progenitor stem cells (bone marrow) for the treatment of tendonitis! The advantages of this approach versus stem cell treatment include reduced cost, on site harvesting and same-day treatment.

Figure 5