Dermoid Sinuses, Dermoid Cysts
Cysts are sac-like cavities that develop within the skin and are filled with fluid, semisolid, cheesy or doughy material. Cysts come in several different varieties, including follicular or epidermoid, dermoid, apocrine and sebaceous duct cysts.
Dermoid cysts, also called dermoid sinuses, are rare developmental abnormalities that may occur as single or multiple lesions resembling follicular cysts. They are identical to human lesions with the same name. They often develop along the back (as in Rhodesian Ridgebacks) but may be found in other areas. Boxers and Kerry Blue Terriers are reported to have an increased incidence. Dermoid cysts have also been reported in cats. Because this is a congenital anomaly, affected animals are usually young. The condition is thought to be inherited via a simple recessive gene.
Dermoid cysts are similar to epidermoid cysts but are more complex in structure and are also found in ovaries and testicles.
Nasal dermoid sinus is not common in dogs. This sinus resembles a small fistula in the midline of the bridge of the nose, intermittently producing discharge.
Signs of Dermoid Sinuses
A small pore usually connects the cyst to the skin surface, and hair may protrude through the pore. In some cases, the cysts may extend deep into the dog's back to the level of the meninges and need to be evaluated radiographically.
Treatment of Dermoid Sinuses
Therapy consists in surgical removal of the cyst and the prognosis is usually good. Attempted manual expulsion of the cyst content using finger pressure should not be performed under any circumstances since rupture of the cysts may result in intense local skin irritation and inflammation. The nasal dermoid cysts need to be removed completely.
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