Benign Histiocytoma in Dogs

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Upon petting or grooming a dog, you may discover suspicious lumps and bumps. Just as in humans, the presence of any suspicious growths on the skin should receive medical attention. It may turn out to be nothing, but it is best to practice the "better safe than sorry" protocol.

Histiocytoma in dogs, for instance, is a benign tumour that a veterinarian should see nevertheless, to rule out other other serious conditions.


Histiocytomas are small, round, hairless growths that can grow on any part of the dog's body but are most commonly found on the dog's head. A histiocytoma will generally appear rapidly as a solitary mass that will often ulcerate but then eventually get smaller and go away. These growths are benign and are not considered to be a health risk to the dog, according to the Veterinary & Aquatic Services Department of Drs. Foster & Smith in an article on Pet Education.


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While histiocytomas can appear at any time in a dog's life, they tend appear more frequently in young dogs, mostly under 2 years old. Some breeds of dogs appear to be more predisposed to developing histiocytomas, including Labrador retrievers, Staffordshire terriers, boxers and dachshunds, according to Wendy C. Brooks, DVM, educational director of Veterinary Partner.


Upon viewing the growth, most veterinarians may want to carefully examine it in depth by performing a biopsy and sending the collected specimen out to a lab for proper analysis. She will perform a skin biopsy by snipping off a small part of the growth. This procedure may require sedation depending on the location of the growth and the dog's temperament. Sometimes the use of a local anesthetic will suffice. Another option is to withdraw cells from the growth with a needle or simply collect them by pressing a microscope slide against the growth. While these procedures may be less accurate than the actual biopsy, it may be enough for the lab to come to a diagnosis, explains Dr. Brooks.


Self diagnosing a dog with a growth may be tempting but this practice is highly discourages. Some malignant growths in dogs may resemble and be confused for histiocytomas. For instance, malignant round cell tumours, such as mast cell tumours or solitary cutaneous lymphomas, can very closely mimic the appearance of benign histiocytomas. For this reason, some cautious oncologists may decide to remove the histiocytic tumours, according to Vet to the Pet, a veterinarian practice based in New York.


Owners of dogs with histiocytoma may feel relieved in knowing that often no treatment is required as the histiocytoma will go away on its own, generally within three months. At times, the growth may cause itchiness, ulcerate and undergo minor infection. In these cases, a vet may prescribe topical steroids and antibiotics for relief. In some cases, the vet may need to remove histiocytomas, depending on their location and if they are bothering the dog, according to the Veterinary & Aquatic Services Department of Drs. Foster & Smith.