Dermoid Sinus
By: Diane Jacobsen
| Dermoids after they have been removed. |
| Removed dermoids. |
Dermoid Sinus (for pictures see the Vet article)
Dermoid Sinus in the Rhodesian Ridgeback Puppy
The dermoid sinus (D.S.) has been known by many names, a
few of which are dermoid cyst, hair cyst, and African cyst. It is
a sinus, in that it is tube like and does drain, and dermoid
because it is skin like. It may or may not contain hair follicles
or be lined with hair. As the hair sheds on the outer coat of the
pup, so does the hair inside this tube. The body's natural
response to dead material is to flush it out and thus the
serum builds up and expels the debris. Not all of the dermoid
sinuses are true tubes. Some are not hollow and the serum
and debris cannot drain. In these cases an abscess forms
and the resulting swelling that accompanies can rupture the
skin. This results in a very painful situation for the pup. At its
worst it is life threatening.
The D.S. is generally found on the mid-line of the neck, back,
and tail along the spinal column. Although rarely found in the
ridge there have been several cases noted. Dermoid sinuses
have also been noted on ridgeless puppies.
The D.S. is a congenital condition, meaning that it is present
at birth. It can be palpated on the newborn pups, and the
affected pups identified. The affected pups should be put to
sleep or if they are to be kept, surgery to remove the D.S.
should be performed before sending them to their new
homes. The affected pups are pet stock only and should not
be considered as breeding material.
To find the D.S. you must palpate along the mid-line of the
spine, starting at the top of the head close to the occiput
(bump) bone. To do this you may pick the pup up and hold it
in the cup of your hand or palpate as the pup is sleeping.
Take the other hand and envision yourself picking up a
baby kitten by the scruff of the neck with your thumb and
forefinger. Exert enough pressure to feel, but not enough to
bruise. 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 D.S., being attached on the top
to the skin and at the base to the spinal cartilage, will slip
through your fingers. A large D.S. will feel like a wet noodle
and a finer D.S., like a small 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 tail.
At the tail it is very difficult to raise enough skin to palpate
effectively. It is best to use your thumb in this area. With
fingers underneath the pup supporting it, place the flat of your
thumb over the spinal column at the pelvic area. Push skin
first to one side and then back to the other side. Again,
remember that the D.S. is attached and will slip under your
thumb. This will feel like a squiggly noodle on a larger, longer
D.S., or just an area that simply will not move at all on a
shorter D.S. If you do not feel anything by sliding the skin from
side to side, try sliding the skin toward the nose and then
back to 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 D.S. is easily traced from the muscle to the top of
the skin and feels round.The D.S. can be visually detected by
looking for a group of hairs that protrude straight up out of the
hair coat of the pup. When you see this, the pup should be
palpated for a D.S. The hair can also be shaved at this site
and upon examination, a small dimple will be revealed. By
moving the skin back and forth, the dimple will become more
apparent as the anchor of the D.S. will pull the skin down
more.
The D.S. can be surgically removed. It is advised that a vet be
contacted that is familiar with this condition and has
performed this operation before. Dermoid sinuses are not
alike in their makeup and it is impossible to tell which ones
are easily removed or which ones go to the spine. They can
wrap around or enter the area of the spinal cord, which
makes them almost, if not impossible, to remove. In cases
such as this some success has been achieved by folding the
D.S. over and tying it off, but some have had regrowth. Since
there is no way to detect which type of D.S. that the pup has,
instructions to the vet should include that if the D.S. is not
completely removable, the pup be put to sleep. D.S. pups
should not be promised to a new home until after the surgery.
The healing process can be as traumatic as the operation
itself. In the simple cases that remove easily, there will be
little or no serum build-up in the surgical area. In the more
complicated surgeries, where the tissue damage has been
more severe, the serum 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. This requires aspiration
with a large gauge needle and syringe, sometimes three or
four times daily, to remove the serum build-up. This can last
for three to 10 days after surgery.
Pups that have had surgery must be removed from the litter to
prevent damage to the surgical site. As puppies play, they
grab and shake areas of skin on the other pups. If they were
to grab and shake over or near the surgical site, damage
would occur and the serum buildup would become a bigger
problem.
Dermoid sinuses have been detected on other parts of the
body, but are not as commonly seen as on the mid-line of the
spine. A few have been noted on the head, attaching to the
skull or the base of the ear. Another area of note is on the
neck under the ear or on the front of the neck. Sometimes
these can be dermoid sinuses and sometimes they are skin
tabs.
The exact mode of the inheritance of the D.S. is not known. It
is thought to be polygenic (multiple genes), rather than
simple dominant or recessive. It has been noted that there
can be carriers, or individuals that produce more dermoid
sinuses than their litter mates. Some lines are relatively D.S.
free. Dogs that are subjects of D.S. are not candidates for a
breeding program. The surgery removes the visual defect but
not the genetic one. Pups having had surgery to remove a
D.S. are eliminated from the conformation ring as per the AKC
rules, which clearly state that a dog that has been surgically
altered cannot compete.The ethics of breeding require you to
put the best possible representative of the breed out there. It
should not only look like a Rhodesian Ridgeback, but it
should be as healthy and sound as possible. As the D.S. is a
very serious unsoundness, much thought should be given in
your decision of the disposition of a D.S. puppy. If you decide
to keep and operate on a D.S. subject, care must be taken to
assure the pup of a home that will spay or neuter. Euthanasia
is a permanent solution.
[NOTE: Because of the D.S., avoid injections in the area of the
top of the neck and shoulders.
Occasional reactions to vaccines can produce an
inflammation that resembles a D.S.]
Dermoid Sinus in the Rhodesian Ridgeback Puppy
The dermoid sinus (D.S.) has been known by many names, a
few of which are dermoid cyst, hair cyst, and African cyst. It is
a sinus, in that it is tube like and does drain, and dermoid
because it is skin like. It may or may not contain hair follicles
or be lined with hair. As the hair sheds on the outer coat of the
pup, so does the hair inside this tube. The body's natural
response to dead material is to flush it out and thus the
serum builds up and expels the debris. Not all of the dermoid
sinuses are true tubes. Some are not hollow and the serum
and debris cannot drain. In these cases an abscess forms
and the resulting swelling that accompanies can rupture the
skin. This results in a very painful situation for the pup. At its
worst it is life threatening.
The D.S. is generally found on the mid-line of the neck, back,
and tail along the spinal column. Although rarely found in the
ridge there have been several cases noted. Dermoid sinuses
have also been noted on ridgeless puppies.
The D.S. is a congenital condition, meaning that it is present
at birth. It can be palpated on the newborn pups, and the
affected pups identified. The affected pups should be put to
sleep or if they are to be kept, surgery to remove the D.S.
should be performed before sending them to their new
homes. The affected pups are pet stock only and should not
be considered as breeding material.
To find the D.S. you must palpate along the mid-line of the
spine, starting at the top of the head close to the occiput
(bump) bone. To do this you may pick the pup up and hold it
in the cup of your hand or palpate as the pup is sleeping.
Take the other hand and envision yourself picking up a
baby kitten by the scruff of the neck with your thumb and
forefinger. Exert enough pressure to feel, but not enough to
bruise. 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 D.S., being attached on the top
to the skin and at the base to the spinal cartilage, will slip
through your fingers. A large D.S. will feel like a wet noodle
and a finer D.S., like a small 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 tail.
At the tail it is very difficult to raise enough skin to palpate
effectively. It is best to use your thumb in this area. With
fingers underneath the pup supporting it, place the flat of your
thumb over the spinal column at the pelvic area. Push skin
first to one side and then back to the other side. Again,
remember that the D.S. is attached and will slip under your
thumb. This will feel like a squiggly noodle on a larger, longer
D.S., or just an area that simply will not move at all on a
shorter D.S. If you do not feel anything by sliding the skin from
side to side, try sliding the skin toward the nose and then
back to 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 D.S. is easily traced from the muscle to the top of
the skin and feels round.The D.S. can be visually detected by
looking for a group of hairs that protrude straight up out of the
hair coat of the pup. When you see this, the pup should be
palpated for a D.S. The hair can also be shaved at this site
and upon examination, a small dimple will be revealed. By
moving the skin back and forth, the dimple will become more
apparent as the anchor of the D.S. will pull the skin down
more.
The D.S. can be surgically removed. It is advised that a vet be
contacted that is familiar with this condition and has
performed this operation before. Dermoid sinuses are not
alike in their makeup and it is impossible to tell which ones
are easily removed or which ones go to the spine. They can
wrap around or enter the area of the spinal cord, which
makes them almost, if not impossible, to remove. In cases
such as this some success has been achieved by folding the
D.S. over and tying it off, but some have had regrowth. Since
there is no way to detect which type of D.S. that the pup has,
instructions to the vet should include that if the D.S. is not
completely removable, the pup be put to sleep. D.S. pups
should not be promised to a new home until after the surgery.
The healing process can be as traumatic as the operation
itself. In the simple cases that remove easily, there will be
little or no serum build-up in the surgical area. In the more
complicated surgeries, where the tissue damage has been
more severe, the serum 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. This requires aspiration
with a large gauge needle and syringe, sometimes three or
four times daily, to remove the serum build-up. This can last
for three to 10 days after surgery.
Pups that have had surgery must be removed from the litter to
prevent damage to the surgical site. As puppies play, they
grab and shake areas of skin on the other pups. If they were
to grab and shake over or near the surgical site, damage
would occur and the serum buildup would become a bigger
problem.
Dermoid sinuses have been detected on other parts of the
body, but are not as commonly seen as on the mid-line of the
spine. A few have been noted on the head, attaching to the
skull or the base of the ear. Another area of note is on the
neck under the ear or on the front of the neck. Sometimes
these can be dermoid sinuses and sometimes they are skin
tabs.
The exact mode of the inheritance of the D.S. is not known. It
is thought to be polygenic (multiple genes), rather than
simple dominant or recessive. It has been noted that there
can be carriers, or individuals that produce more dermoid
sinuses than their litter mates. Some lines are relatively D.S.
free. Dogs that are subjects of D.S. are not candidates for a
breeding program. The surgery removes the visual defect but
not the genetic one. Pups having had surgery to remove a
D.S. are eliminated from the conformation ring as per the AKC
rules, which clearly state that a dog that has been surgically
altered cannot compete.The ethics of breeding require you to
put the best possible representative of the breed out there. It
should not only look like a Rhodesian Ridgeback, but it
should be as healthy and sound as possible. As the D.S. is a
very serious unsoundness, much thought should be given in
your decision of the disposition of a D.S. puppy. If you decide
to keep and operate on a D.S. subject, care must be taken to
assure the pup of a home that will spay or neuter. Euthanasia
is a permanent solution.
[NOTE: Because of the D.S., avoid injections in the area of the
top of the neck and shoulders.
Occasional reactions to vaccines can produce an
inflammation that resembles a D.S.]
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