Tricholemmomas are benign, rare hair follicle tumors that develop on the heads of dogs. Poodles are prone to these tumors, manifesting as hard, oval lumps, 0.4 to 2.75 inches (1 to 7 cm) wide. They may develop into funnel-shaped cysts called trichofolliculomas, though this is very rare.
Trichoepitheliomas are numerous little lumps where compressed, yellow, coarse material fills up a whole hair follicle. Whether malignant or benign, they tend to affect mostly the skin of the face. The majority of these tumors usually appear during late middle age, though they can occur at any age. Majority of susceptible breeds include Golden Retrievers, Basset Hounds, Standard Poodles, Irish Setters, Bull Mastiffs, and English Springer Spaniels. Trichoepitheliomas can form anywhere on the body, especially on the trunk. Benign tumors manifest as cysts under or in the skin. Self-trauma or development of the cysts may result in skin ulcers. Surgical removal is the usual mode of treatment. On the other hand, dogs that have one such tumor are likely to develop new ones at other locations, especially English Springer Spaniels and Basset Hounds.
Malignant Trichoepitheliomas are not as common as the benign variety. Once they extend to the surface of the skin, they cause severe inflammation, fibrosis, and tissue death. These tumors don’t usually spread to other organs. During the usual surgical treatment, your veterinarian will take out tissue around the tumor to lessen the likelihood of it returning.
Histiocytic Cell Tumors
Histiocytic Cell Tumors develop a cluster of weakly defined skin diseases all regarded as a production of cells called histiocytes (tissue macrophages), whose cause is not known.
Malignant histiocytosis affects mostly Bernese Mountain dogs. This variant initial appears in the inner organs and lungs, resulting in pain, illness, and eventually death.
Systemic histiocytosis is an aggressive skin disease that leads to numerous skin lesions that wax and wane. It mostly affects Bernese Mountain dogs, and ultimately becomes progressive.
Histiocytomas are ordinary skin tumors typically seen in younger dogs that are less than 3½ years old, though they can crop up in dogs of any age. Scottish Terriers, English Bulldogs, Greyhounds, Boston Terriers, Boxers and Chinese Shar-Peis are most at risk. The tumors appear as solitary, raised, generally ulcerated lumps that are freely movable. The head, ears, and limbs are the most common sites affected. Canine histiocytomas are generally considered benign tumors; most resolve suddenly and with no treatment within 2 to 3 months. Diagnosis is through microscopic inspection of samples of the tumor cells from fine needle aspiration or biopsy. Surgical removal is not obligatory and usually performed only if the dog undergoes severe problems.
Keratinized Skin Cysts
There are dogs that develop cysts which are filled with a skin protein called keratin. These cysts have a firm core, and may be the same colour as the hair. There are a number of keratinized skin cysts. Some types seen in dogs include dermoid cysts (hereditary), isthmus catagen cysts, hybrid cysts (panfollicular cysts), and matrix cysts. Keratinized Skin Cystsare frequently found in Boxers, Rhodesian Ridgebacks, and Kerry Blue Terriers. Dermoid cysts are genetic, compound, and include hair shafts that are completely formed. Diagnosing the condition involves confirming the presence of cysts on the dog, with treatment often being surgical removal. Do not try to remove the cysts by pressing them as this can spread the contents of the cyst into the adjacent tissues, causing your dog’s body to develop serious inflammation.