Important Note for Vets/Breeders/Owners about the Dermoid Sinus Cyst
Reputable breeders should palpate their puppies for the dermoid sinus cysts regularly right up to the time they are ready to go to their new homes.
It is recommended also that new owners get their puppy checked by a vet that is familiar with and has experience of the condition. New owners are advised to continue to check their puppy regularly themselves for the first few months.
The Dermoid sinus is a congenital defect meaning it is present from birth. This condition is very similar to a pilonidal sinus/cyst in humans. As in the human’s pilonidal sinus, the dermoid sinus cyst will become repeatedly infected if not surgically removed. Some dermoids however, are difficult to detect such as those on or near the tail. Unfortunately, many unethical or inexperienced breeders do not screen their puppies for DS, and may not even know how to correctly.
Most dermoid sinuses are relatively easy to remove by a qualified veterinary surgeon, but some can be surgically challenging. We strongly recommend consultation with a Veterinarian experienced in Dermoid sinus surgery.
Additionally, veterinarians should be aware that some DS, particularly those on or near the tail, can consist of a closed sac where you do not feel the “noodle-like” presentation of the “classic” neck DS.
A dermoid sinus in the tail is the hardest to detect and can be missed by even the most experienced of breeders. Which is why it is important that new owners continue to check their pups when they get them home for the first couple of months.
And your puppy is sold with a health guarantee.
The noodle shape of this Dermoid Sinus cyst is seen by picking up the skin.
Removal of a Dermoid Sinus Cyst in Thailand
WARNING Very Graphic
Dermoid Sinus Cyst in the Thai Ridgeback
The dermoid sinus (DS) is known by several names, dermoid sinus cyst, hair cyst, and African cyst. It is called a sinus as in it is a cavity that results within a tube, formed by improper separation during development of the canine embryo, and dermoid because it is made of skin. These tubes may or may not contain hair follicles. If they do, as the hair sheds on the outer coat of the dog so does the hair inside these tubes. The body's natural response to dead material is to flush it out, thus serum and matter builds up resulting in a painful 'cyst' that tries to expel this debris. Not all dermoid sinuses are tubelike or have openings in the outer skin. Some are sealed off and the body cannot drain the serum and debris. In these cases an abscess forms and the resulting buildup of matter built over time, can rupture the (sinus) if not removed. Allowing the matter and bacteria to spread into surrounding areas of the body. This can result in a meningitis like infection of the brain in those DS attached to the spine. Ending in a very painful, very dangerous and possibly life threatening situation for your dog.
The Dermoid sinus cyst (DS) affects the midline of the neck, back, and tail, along the spinal column of the dog. They may or may not be attached to the spine. Although rare there have been cases found in the ridge area too. Dermoid sinuses can also been found in ridgeless puppies and other species of mammals. The DS is a congenital condition, meaning that it is present at birth. It can be palpated (felt) for on puppies from around two weeks of age, and the breeder should be able to detect those pups affected. Any affected pups should have surgery performed to remove the DS by the breeder, before selling them to any new homes. The affected pups are pet stock only and should not be considered as breeding material. And therefore it is recommended that these pups be spayed or neutered and removed from the gene pool.
To find a Dermoid Sinus you must palpate along the midline of the spine, starting at the top of the head close to the occiput (bump) bone on the head. To do this pick the pup up and place it in your lap and check once the pup is sleeping. Take one hand and envision yourself picking up a baby kitten by the scruff of the neck with your thumb and forefinger on the other hand. Exert enough pressure to feel, and slide the skin between your fingers. Use your whole hand as one unit, pulling first up toward the nose and then down toward the tail. The skin will stretch quite a bit in both directions. Do not roll the skin through your fingers. The fingers remain exactly where you placed them on the skin. The DS, being attached to the top of the skin and at the base to spinal cartilage, will slip through your fingers. A large DS will feel like a wet noodle and a finer DS, like a thin string. Reposition your fingers on the neck just below the starting spot and repeat this process. Continue to work your way down the neck and back to the tip of the tail.
It is very difficult to raise enough skin on the tail to palpate this area effectively. It is best to use your thumb in this region with your hand underneath the pup supporting it. Then place the flat of your thumb on top of the tail, starting at the base of it. Push the skin first to one side, then back to the other side. Again, remember that the DS is attached and you should feel it slip under your thumb. This will feel like a squiggly noodle on a larger, longer DS, or just an area that simply will not move on a shorter DS. If you do not feel anything by sliding the skin from side to side, then try sliding the skin forwards and backwards on the tail, taking care to slide the skin... not your thumb!
As you palpate the area over the shoulders, you may feel connective tissue that holds the skin to the shoulder area. The tissue is heavier in this area than in the other areas of the spinal column. It will feel flat and you will not be able to trace it from the area close to the muscle all the way to the skin, whereas the DS is easily traced from the muscle to the top of the skin and feels round.
The DS can sometimes be visually detected by picking up the skin or looking for a group of hairs that protrude straight up out of the coat of the pup. This is usually around 3 to 5 weeks of age. When you see this, the pup should be palpated for a DS, the hair can also be shaved at this site and upon examination; a small dimple or hole will be revealed. By moving the skin back and forth, the dimple will become more apparent as the anchor of the DS will pull the skin down more in that area.
[It should also be noted puppies can be affected by more than one DS. I have personally known of as many as six DS removed from one dog]
All DS should be surgically removed from any affected puppies before the puppy is sold. It is advised that a vet who is familiar with this condition and has performed this type of surgery before, be contacted. The surgery should be done as early as 6 weeks and it is strongly advised that it be preformed prior to 5 months. This is because the DS will grow in size with the dog and becomes more invasive the longer it is left untreated. Success rates for surgical removal and recovery will go down the older the dog is.
Dermoid sinuses are not alike in their makeup and it is impossible to tell the severity of the DS and how challenging it will be to remove. The more severe cases are connected to the spine. They can also wrap around or enter the area of the spinal cord, which makes them almost, if not impossible to remove. In these cases some success has been achieved by folding the DS over and tying it off, however some cases have had regrowth. Since there is no way to know which type of DS a pup has until surgery, it is suggested that the instructions to the vet should include that if the DS is not completely removable, the pup be put to sleep. DS pups should not be promised to a new home until after they have had successful surgery to remove the Dermoid sinus.
The healing process can be as traumatic as the operation itself. In the simple cases that remove easily, there will be little or no fluid build-up in the surgical area. In the more complicated surgeries, where surgery has been more intrusive and the tissue damage has been more severe, the fluid will start building up as soon as the surgical site heals over on the top of the skin. Usually this will be on the fourth or fifth day. It is sometimes necessary to drain this fluid or put in a surgical drain, but it heals faster and better if left alone! About 5 to 8 days later the body will begin to absorb the fluid. There will be a slight swelling for a while but that too will go.
Thai ridgeback puppies, that have had surgery must be removed from its littermates to prevent damage to stitches or infection. As puppies play, they grab and shake areas of skin on the other pups. If they were to shake or bite near the surgery site, infection can occur and the serum buildup becomes a bigger problem. A pressure bandage over the site of surgery on the neck i've found helps keep the swelling down, but check it often that it is loose enough under the neck so the puppy can eat and most importantly breathe!
Dermoid sinuses have in rare case been detected in other areas of the dog. The most common site for a DS is the midline of the spine. But there have been recorded cases noted on the head, attached to the skull or the base of the ear. Other areas of note are the neck area under the ear and down the sides of the neck or at the front of the neck.
The exact mode of inheritance of the DS is unknown. It is thought to be polygenic (multiple genes), rather than simply dominant or recessive. Its been observed that there can be carriers, or individuals that produce more DS cases than their siblings. Some lines are relatively DS free, but there are no.... DS 'free' lines so beware of any breeder who says this. Dogs with a DS are not suitable for breeding. Surgery removes the visual defect but not the genetic one. Pups having had surgery to remove a DS are eliminated from the conformation ring as per the UK KC rules, which clearly state that a dog that has been surgically altered cannot compete.
The ethics of breeding requires the breeder to put the best possible representative of the breed forward. It should not only look like a thai ridgeback, but it should be as healthy and sound as possible too. As the DS is a very serious unsoundness, much thought should be given in your decision of the placement of a DS puppy. If you decide to keep and operate on a DS puppy, care must be taken to assure the pup of a pet home that will spay or neuter the puppy when old enough to remove the dog from the gene pool.
[Note to Breeders]. Because of the possibility of an undetected DS, ask the vet to avoid injections in the area of the top of the neck and shoulders. Occasionally reactions to vaccines can produce an inflammation that resembles a DS.
Warning - this page contains graphic photos & video footage which may be disturbing to viewers
Pictures A and B show examples of outward signs your puppy has a Dermoid cyst.
Picture C shows the removal of two Dermoid cysts attached together.