Dermoid sinus is thought to be a genetic skin condition in dogs. It is also known as ''pilonidal sinus''. However, unlike
pilonidal sinus
Pilonidal disease is a type of skin infection which typically occurs as a cyst between the cheeks of the buttocks and often at the upper end. Symptoms may include pain, swelling, and redness. There may also be drainage of fluid, but rarely a fev ...
in humans, the dermoid sinus in dogs is a
neural tube defect
Neural tube defects (NTDs) are a group of birth defects in which an opening in the spine or cranium remains from early in human development. In the third week of pregnancy called gastrulation, specialized cells on the dorsal side of the embryo ...
. Dermoid sinus is sometimes also confused with
dermoid cyst
A dermoid cyst is a teratoma of a cystic nature that contains an array of developmentally mature, solid tissues. It frequently consists of skin, hair follicles, and sweat glands, while other commonly found components include clumps of long hair, ...
(a
teratoma
A teratoma is a tumor made up of several different types of tissue, such as hair, muscle, teeth, or bone. Teratomata typically form in the ovary, testicle, or coccyx.
Symptoms
Symptoms may be minimal if the tumor is small. A testicular terato ...
).
A dermoid sinus is rare in dogs and cats. It can appear as single or multiple lumps on the
dorsal
Dorsal (from Latin ''dorsum'' ‘back’) may refer to:
* Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism
* Dorsal, positioned on top of an aircraft's fuselage
* Dorsal co ...
midline. The sinus is caused in the embryonic stage of development. In normal development, the neural tube from which the spine develops separates from the skin. In the case of a dermoid sinus, this separation has not fully taken place. The result is that in some cases, the dermoid sinus remains connected to the animal's spinal cord; in other cases, the sinus terminates in a "blind sac" that is less dangerous to remove.
Histologically
Histology,
also known as microscopic anatomy or microanatomy, is the branch of biology
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single ...
, the dermoid sinus contains
hair follicle
The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction between h ...
s,
sebaceous gland
A sebaceous gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur in the greatest number ...
s, and
sweat gland
Sweat glands, also known as sudoriferous or sudoriparous glands, , are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial sur ...
s. If the sinus becomes infected, it can result in
meningitis
Meningitis is acute or chronic inflammation of the protective membranes covering the brain and spinal cord, collectively called the meninges. The most common symptoms are fever, headache, and neck stiffness. Other symptoms include confusion or ...
and
myelitis
Myelitis is inflammation of the spinal cord which can disrupt the normal responses from the brain to the rest of the body, and from the rest of the body to the brain. Inflammation in the spinal cord, can cause the myelin and axon to be damaged re ...
, symptoms of which are spinal pain, rigidity, and fever. In serious cases, the condition can be life-threatening.
The dermoid sinus gene is believed by some to be recessive, meaning that the animal must receive one defective gene from each parent in order to develop the condition. Where one parent carries the gene and the other does not, the offspring remain carriers and can continue to pass the defective gene on to their offspring in turn. Others believe that the dermoid sinus condition is more appropriately characterized as
polygenic
A polygene is a member of a group of non-epistatic genes that interact additively to influence a phenotypic trait, thus contributing to multiple-gene inheritance (polygenic inheritance, multigenic inheritance, quantitative inheritance), a type of ...
, involving multiple genes.
[See Jacobsen, supra. http://rrcus.org/assets/html/breedinfo/dermoid/dermoid.htm ] In any case, because of the genetic nature of this potentially dangerous condition, most breeders and veterinarians advise against breeding animals that have a dermoid sinus, or have a parent that is known to carry the gene.
Surgical excision is the only remedy for this condition, with veterinary surgeons removing abnormal tissue and closing any connections to the spine, In some cases, regrowth of the sinus occurs. A variety of tests, such as a
myelogram
Myelography is a type of radiographic examination that uses a contrast medium to detect pathology of the spinal cord, including the location of a spinal cord injury, cysts, and tumors. Historically the procedure involved the injection of a radioco ...
or a
fistulogram may be undertaken to determine how deep the sinus goes. Other, more basic tests, such as a
complete blood count
A complete blood count (CBC), also known as a full blood count (FBC), is a set of medical laboratory tests that provide cytometry, information about the cells in a person's blood. The CBC indicates the counts of white blood cells, red blood cell ...
,
biochemical profile
Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology and ...
, and
urinalysis
Urinalysis, a portmanteau of the words ''urine'' and ''analysis'', is a panel of medical tests that includes physical (macroscopic) examination of the urine, chemical evaluation using urine test strips, and microscopic examination. Macroscopic e ...
can be performed to determine if infection or other problems exist.
Computed tomography
A computed tomography scan (CT scan; formerly called computed axial tomography scan or CAT scan) is a medical imaging technique used to obtain detailed internal images of the body. The personnel that perform CT scans are called radiographers ...
scans and
magnetic resonance imaging
Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to form pictures of the anatomy and the physiological processes of the body. MRI scanners use strong magnetic fields, magnetic field gradients, and radio wave ...
may be undertaken to determine if neurological signs exist as a result of the sinus.
[See Spielman, supra. http://www.petplace.com/dogs/dermoid-sinus/page1.aspx]
Breeds known to be affected include
Rhodesian Ridgeback
The Rhodesian Ridgeback is a large dog breed bred in the Southern Africa region. Its forebears can be traced to the semi-domesticated ridged hunting and guardian dogs of the Khoikhoi. These were interbred with European dogs by the early colonist ...
,
Phu Quoc Ridgeback
The Phu Quoc Ridgeback (Vietnamese: ''Chó Phú Quốc'') is a rare breed of dog from the island of Phú Quốc in Kiên Giang Province in southern Vietnam. It is one of three ridgeback breeds, the others being the Rhodesian Ridgeback and the ...
, and
Thai Ridgeback
The Thai Ridgeback ( th, ไทยหลังอาน, ) is a dog from Thailand. The Thai Ridgeback is one of only three breeds that has a ridge of hair that runs along its back in the opposite direction to the rest of the coat. The other tw ...
, in which it is hereditary,
Kerry Blue Terrier
The Kerry Blue Terrier (also known as the Irish Blue Terrier) ( gle, An Brocaire Gorm) is a breed of dog. Originally bred to control vermin including rats, rabbits, badgers, foxes, otters and hares, over time the Kerry became a general working d ...
s,
Shih Tzu
The Shih Tzu (, ; literally " Hsi Shih dog") is a toy dog breed originating from Tibet and was bred from the Pekingese and the Lhasa Apso.
Shih Tzus are known for their short snouts and large round eyes, as well as their long coat, floppy ear ...
s and
Boxer Boxer most commonly refers to:
* Boxer (boxing), a competitor in the sport of boxing
*Boxer (dog), a breed of dog
Boxer or boxers may also refer to:
Animal kingdom
* Boxer crab
* Boxer shrimp, a small group of decapod crustaceans
* Boxer snipe ee ...
s.
[{{cite book, last=Griffin, first=Craig E., author2=Miller, William H. , author3=Scott, Danny W. , year=2001, title=Small Animal Dermatology, edition=6th, publisher=W.B. Saunders Company, isbn=0-7216-7618-9 See also Spielman, supra. http://www.petplace.com/dogs/dermoid-sinus/page1.aspx]
References
External links
Folic acid study
Dog diseases