Innovative advances in cryosurgery offer safe and effective treatment options with unlimited potential in the hands of the veterinarian.
Canine and feline dermatologic problems make up a substantial part of any small and/or mixed animal practice. Lesions ranging from small nodules to lumps and bumps are included in the daily questions clients ask practitioners during routine annual examinations and preanesthetic screenings of their animals. A large percentage of these masses can be benign proliferations of various gland tissues, or accumulations of abnormal but benign cell growths, while others are neoplastic tissues with invasive and metastatic potential. Traditionally, these masses have been excised with a scalpel and/or surgical laser, requiring the use of sedation or general anesthesia. While this has been an industry standard for many years, many patients presenting with skin lesions often have other problems, leading to safety concerns with chemical immobilization. Cryosurgery offers an attractive option for these patients, since it can be utilized with minimal or no sedation, collateral tissue damage and post-operative care.
Advances in cryosurgery
While cryosurgery is not a new modality, the tools used to deliver the required temperature change are evolving, making the target areas very precise. This enhanced precision reduces collateral tissue damage, leading to faster healing and less scarring. The capacity to achieve this precision is also what makes the biggest difference in treating smaller lesions. The specific unit I use in my practice is the CryoProbe X+, which runs at about -127°F. This specific model includes five separate tip sizes that can be used to match the lesion being treated, and can be operated with available 8g and 16g cartridges. (While treatment is often done without sedation or general anesthesia, the locations of some lesions will still require chemical immobilization to achieve desired results). Thanks to the precision of the micro-applicator tips, there is no collateral damage to healthy tissue, resulting in no discomfort to the patient. As such, treatments are very controlled and can be longer in duration if necessary. There is no required post-operative care; there is no bleeding, and sutures and cones are unnecessary, a wonderful benefit for both patients and caregivers. The following discussion identifies common lesions the author has treated with cryotherapy, but the modality’s use is certainly not limited to these.
- Sebaceous adenomas: One of the most common skin ailments of aging and geriatric patients is the sebaceous adenoma. Also known as nodular sebaceous hyperplasia, this lesion is characterized as a benign non-haired soft tissue proliferation with an oily to crusted surface. The depth of abnormal tissue is often very superficial although the tissue can extend deep into the epidermis in some lesions. Cryosurgery is very effective for these, and one treatment is typically curative with very little follow-up required.
- Cutaneous histiocytomas: Cryosurgery is very useful in the treatment of cutaneous histiocytomas. These benign and often solitary tumors often appear in places wheresurgical excision can be difficult. When they appear on the head, digits and ears, there is little room for excising while obtaining adequate margins without cosmetically affecting the closure. While these lesions can be deep and relatively dense, I have experienced successful outcomes with cryotherapy in completely resolving lesions as large as 1cm in diameter and ½cm in height. Larger masses may require an additional treatment or two to achieve complete resolution
- Mast cell tumors: Mast cell tumors are often highly invasive and metastatic masses that can lead to very debilitating disease; higher grades and stages often result in diffuse systemic involvement. While cryosurgery is not my first line of choice in treating the masses that develop, it can be used as an additional modality to treat smaller nodules within the skin in areas where removal would be difficult. I have successfully treated smaller solitary Grade 1 nodules less than 1cm in diameter, with minimal to no recurrence. When treating these masses, I have found it beneficial to treat the nodule itself, along with 2mm to 4mm margins, and re-treating the same area after thawing has occurred.
- Acral lick granulomas: Cryotherapy can also be used on chronic inflammatory lesions, such as acral lick granulomas, as an additional treatment modality. I have found it useful to intermittently freeze portions of the granulomas, along with using traditional therapies.
- Epidermal and follicular inclusion cysts: These commonly-encountered nodular masses can respond well to cryosurgery. If possible, the author recommends either expressing or draining the lesions of any fluid or material prior to freezing with cryotherapy. This dramatically reduces the time required to freeze the area, permitting more effort to be directed at the tissue responsible for producing the material. If deep tissue nodules are being treated, or if draining of the lesions requires a scalpel or hypodermic needle, heavy sedation or general anesthesia is recommended for patient comfort.
- Meibomian gland adenomas: For meibomian gland adenomas measuring 1mm or less, my preferred initial treatment option is cryosurgery over surgical excision. These common eyelid masses are full thickness proliferations often filled with a material that can be expressed with gentle pressure. I would suggest treating the tissue with cryotherapy from both palpebral and ocular sides to ensure all abnormal tissue is treated. There is little to no cosmetic change after healing.
- Eosinophilic granuloma complex, ulcerative paradental stomatitis and oral neoplasia: Oral lesions such as eosinophilic granuloma complex, ulcerative paradental stomatitis and oral neoplasia that don’t involve bony tissue can be treated with cryotherapy when conventional medical and surgical techniques are not feasible. The lack of excess tissue for closure, despite efforts to elevate from the bone, can make it difficult to surgically close these lesions, leaving some cases to heal by second intention alone. I have used cryosurgery to debulk the main mass or lesions with promising results. I will reassess the areas on a regular basis and elect to refreeze the tissue as often as needed to suppress new growth formation.
Prior to cryosurgery implementation, it is imperative that current standards of care be followed, with appropriate cytological and histopathological diagnostic steps performed as indicated. If a mass is deemed malignant with metastatic potential, addressing the mass with aggressive surgical intervention, radiation and chemotherapy would be indicated based on oncologist recommendations should the patient’s owner elect to pursue that line of treatment. Once a mass has been diagnosed, the use of cryosurgery can be employed for nearly any lesion on the skin, as well as some mucus membrane tissues.
Veterinary practices today are filled with innovative technological advancements that assist us in effectively treating patients in an ethical and compassionate manner. While traditional surgical and medical practices will always provide the foundation for our therapies, additional modalities such as cryosurgery also have their place.
By adding a cryosurgical unit to my treatment toolbox, I have been able to offer another option for commonly-seen dermatological lesions that is quick, effective, less invasive, and requires little to no anesthesia. Cryosurgery has been readily accepted by my clientele and well tolerated by my patients, making it a great fit for my practice.
Disclosure: The work expressed in this article is from Dr. Walrath’s direct clinical experience of using CryoProbe in his private practice since 2016. He is not a paid consultant or remunerated in any way.