By Jon Plant, DVM, DACVD For The Education Center
Originally Published In Veterinary Practice News, May 2020 – Download as a PDF
Sebaceous epitheliomas are a common neoplasm of dogs, arising from the reserve cells of sebaceous glands. They occur most often on the head, ears, and dorsum. Sebaceous epitheliomas rarely metastasize, though they may be locally aggressive and recurrent.
The patient
Oliver, a 13-year-old neutered male Dalmatian-cross dog was presented to SkinVet Clinic for a rapidly enlarging nodule between the digital and metacarpal pads of the left front limb (Figure 1). The 1.5-cm diameter mass was painful, raised, alopecic, and ulcerated. A fine-needle biopsy was inconclusive. A pre-anesthetic complete blood count and chemistry panel found mild liver enzyme elevations, which were stable compared to previous years.
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- Figure 1: Preoperative aspect of a 1.5-cm painful, raised, alopecic, and ulcerated sebaceous epithelioma between the digital and metacarpal pads of the left front limb.
Procedure prep and anesthesia
The patient was premedicated with butorphanol and acepromazine. Anesthesia was induced with alfaxalone and maintained with isoflurane. The patient was placed in lateral recumbency. A ring nerve block with lidocaine and bupivacaine was performed proximal to the carpal pad. Rimadyl was administered subcutaneously.
Surgical technique
A VetScalpel CO2 laser (by Aesculight, Bothell, Wash.) with an adjustable handpiece set to the 0.4-mm focal spot size was utilized at 10 watts (continuous mode) to make an incision around the mass (Figures 2A and 2B). An edge of the mass was then elevated with traction while carefully undermining, cutting, and cauterizing the attachment to the underlying subcutaneous tissue. Bleeding was controlled by defocusing the laser beam. Lastly, the spot size was set to 0.8 mm to ablate the remaining abnormal-appearing tissue with several cycles of “painting” the surface and removal of char with saline-soaked gauze (Figure 2C).
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- Figure 2a: Beginning an incision was made around the mass with a VetScalpel CO2 laser (adjustable handpiece is shown set to 0.4-mm focal spot size).
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- Figure 2b: Continuing the incision was made around the mass with a VetScalpel CO2 laser.
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- Figure 2c: After the epithelioma mass was excised, the laser focal spot size was increased to 0.8 mm and the remaining abnormalappearing tissue was ablated with several cycles of “painting” the surface and removal of char with saline-soaked gauze.
Wound closure and postoperative care
The skin was closed with 3-0 Promend with a continuous subcuticular pattern (Figure 3). The foot was bandaged with silver sulfadiazine-coated non-adherent dressing and a light compression wrap. Simplicef and Rimadyl were dispensed. The bandage was changed at least every three days. Histopathology of the mass found it to be a sebaceous epithelioma (such tumors have the potential to recur). Oliver’s surgical site healed uneventfully, without reoccurrence 10 weeks after the surgery (Figure 4).
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- Figure 3: Immediate postoperative view of the surgical area—the skin was closed with a continuous subcuticular pattern.
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- Figure 4: The surgical site healed uneventfully (seen here 10 weeks post-surgery.)
Summary
This case illustrates how laser surgery is used to remove cutaneous tumors that might otherwise pose more of a challenge. CO2 lasers minimize bleeding, allowing for excellent visualization of the surgical field. Further, they seal nerve endings to minimize pain and provide pinpoint precision. Tissue can readily be ablated layer by layer when needed.
Dermatological indications for CO2 laser surgery at SkinVet Clinic include, among others, skin fold intertrigo, interdigital follicular cysts, cutaneous masses, lipomas, acral lick dermatitis, pinnal masses, apocrine ear cysts, and stenotic nares.
Jon Plant, DVM, DACVD, was an early adopter of the flexible hollow waveguide CO2 laser in veterinary medicine. After 15 years of dermatology referral practice in Southern California, he taught at the Oregon State University, College of Veterinary Medicine, served as a dermatology consultant for Banfield Pet Hospitals and Dechra, founded SkinVet Clinic (skinvetclinic.com) in Oregon, and developed RESPIT allergen immunotherapy. Dr. Plant is a graduate of Reed College and Oregon State University.
This Education Center article was underwritten by Aesculight of Bothell, Wash., manufacturer of the only American-made CO2 laser.
