Cysts are sac-like structures that contain a liquid or semi-solid substance in their center. Cutaneous and subcutaneous cysts are non-cancerous masses of variable sizes that are located within or just beneath layers of the skin. Dermoid cysts, more specifically, are tumors that have a fibrous wall lined with skin - specifically, with stratified epithelium. They contain exfoliated skin, hair, hair follicles, sweat gland secretions, sebaceous gland secretions, nerve remnants and glandular debris. Dermoid cysts are developmental in origin. They originate from the dermis, which is the principal layer of skin lying between the epidermis and the subcutaneous tissue. The dermis is mostly made of a network of collagen fibers. However, it also contains blood vessels, cells, nerves and other fibers. Dermoid cysts primarily develop along the top of the back, which in medical lingo is called the dorsal midline. Occular dermoid cysts can occur in the eyelid, cornea or conjunctiva. Ovarian dermoid cysts have also been reported in domestic dogs. Most cysts, including dermoid cysts, are harmless (benign). However, sometimes they can transition into malignant masses. Cysts also can rupture and become infected and painful to affected dogs.
Dermoid cysts are typically congenital (present at birth) and have a strong suspected hereditary component. They are fairly common in domestic dogs and rare in domestic cats. Dermoid cysts are considered to be developmental in origin, meaning that they develop in utero while the puppy’s cells, tissues and organs are being formed. The underlying cause is thought to be the failure of complete separation of the neural tube from the epidermis during embryogenesis. The neural
Most dogs with dermoid cysts or other forms of cutaneous (skin) or subcutaneous (beneath the skin) cysts are asymptomatic, meaning that they show no outward signs of discomfort, distress, unusual behavior or pain. If a cyst ruptures, it can become quite painful for the animal. They frequently are extremely itchy (pruritic), as well.Owners of a dog with dermoid cysts often bring their dog to the veterinarian for evaluation of soft, fluctuant to semi-solid, non-painful
There are several distinct types of cutaneous (skin) and subcutaneous (beneath the skin) cysts that can be seen in domestic dogs. Typically, cysts are identifiable visually and by physically feeling them on palpation. Dermoid cysts can be distinguished from follicular and infundibular cysts in several ways. A procedure called a fine-needle aspirate can be performed to obtain a tiny sample of the internal cyst material. This involves inserting a sterile needle into the center of
The goals of treating dermoid cysts are to remove them and, hopefully, to prevent their recurrence. Surgical excision is the treatment of choice. Depending upon the size and location of the cysts, removal may be done under sedation and local anesthesia, or it may require general anesthesia. Usually, the surgical procedure is quite simple. Occasionally, however, the site of the cysts may become inflamed and infected postoperatively. If that happens, oral antibiotics and topical medicated