Sarcoids in a Horse

The following images represent 3 different cases of sarcoid tumors in horses. The images in Figure 1 and 2 are that of sarcoid tumors on a horse's hind limb. The tumors had been removed several times before however they continue to re-develop. The sarcoid tumors in this case have been treated by surgical resection and a topical anti-sarcoid medication called Xxterra. This gelding will require additional surgical debulking and more aggressive post-operative treatment with cryotherapy AND chemotherapy agents. Prognosis is guarded due to the large tumor size and the location of the sarcoid tumors.
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Figure 1

Figure 2

In Figures 3,4 and 5, the sarcoid tumor in this horse is located along the sheath of the gelding and is flatter compared to the sarcoid tumors in the horse in Figures 1 and 2. This sarcoid was treated with multiple injections of a chemotherapy agent known as cisplatin. There was minimal response to the chemotherapy agent hence this sarcoid tumor will likely require surgical debulking followed by additional chemotherapy treatment.

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Figure 5

The gelding in Figure 6 and 7 was suffering from a horrible sarcoid that weighed more than 2 pounds and was dangling from his right ear. The sarcoid was removed by surgical debulking and the ear was treated with both injectable cisplatin and cryotherapy (liquid nitrogen). The image in Figure 7 is several months after the initial surgical debulking. To date, there does NOT appear to be any re-development of the sarcoid tumor.

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Figure 7

These 3 cases represent the diversity of the appearance and location of sarcoid tumors in horses!  However, what they have in common is the aggressive and persistent nature of sarcoid tumors in horses. As such, the take home message of these cases is that sarcoid tumors should be identified EARLY and treated as AGGRESSIVELY as possible. There is no ONE treatment that is typically suffice for treatment but rather a combination of surgical debulking, chemotherapy and cryotherapy!

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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Figure 5

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.

Figure 8

Squamous Cell Carcinoma in a Horse

The images below are from 3 different horses with the same disease. Squamous cell carcinoma is a type of cancer that tends to affect the lightly pigmented areas of horses. These areas include the penis (Figures 3-4), sheath (Figures 1-2), muzzle (Figures 5), anus, and the eye lids. Diagnosis should be confirmed via a biopsy and histopathology. This type of cancer does not commonly metastasize to other regions of the body but is locally aggressive. As such, early intervention is the most important component to effectively treating this cancer.

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Figure 2

Once the diagnosis of squamous cell carcinoma (SCC) has been confirmed it is my opinion that surgical resection of the tumor should be attempted. This is easier said than done and in some cases surgical removal is not a reasonable option. In some cases, if the lesion is small yet not surgical, cryotherapy with liquid nitrogen can be highly effective. Cryotherapy is recommended for carcinomas near the muzzle and on the penis.  Once the tumor has been removed or if it is not surgical, I recommend proceeding with intra-lesional chemotherapy agents to attack any remaining cancerous cells. It is common to repeat the intra-lesional chemotherapy treatment multiple times.

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Figure 4

 It is very important to aggressively treat SCC! The horse in Figure 5 was treated with only surgical resection. Within months of surgery, the tumor returned and invaded the oral cavity. There were no more options for this horse. Horses with SCC need to be treated early and repeatedly until there is no evidence of any remaining cancerous tissue!!

Figure 5