Bulldog Health: Histiocytoma or Button Tumor

Roxy's histiocytoma, April 6, 2012. Notice classic button shaped appearance.
Like all bullies, Roxy plays rough. So when she suffered a small laceration on her snout from a robust French bulldog that developed into a flat, pink scar, we weren't concerned. The scar persisted for months without incidence, then suddenly, within a week, grew into a round, red, fleshy tumor. Was it cancer? An infection? But how could that be, so many months after the injury, and why did it grow so rapidly?

Our vet told us that based on the lesion's appearance and Roxy's young age (1 year), it was almost certainly a histiocytoma or button tumor. She reassured us that it was a benign growth common in young dogs that would most likely regress over the next few months. Unless it became infected, caused discomfort, bled or persisted for too long, there was little need for intervention or removal.

According to PetMD.com, histiocytomas are more common in flat-coated retrievers, bull terriers, boxers, dachshunds, cocker spaniels, Great Danes, and Shetland sheepdogs. Symptoms are:
  • Small, firm, dome or button-shaped masses on the skin surface
  • Rare autoimmune blistering (dermoepithelial) masses, which may be ulcerated
  • Fast growing, nonpainful, usually solitary
  • Common sites are the head, ear edges, and limbs
  • Occasionally multiple skin nodules or plaques
Our vet couldn't explain why Roxy's scar developed into a histiocytoma, however, upon further research I learned that histiocytomas are made of Langerhans cells, specialized cells that are an essential part of a dog's immune system. And although most sources couldn't explain why they occur in young dogs, according to Maria Hiltner (who cites Joan Rest's 2008 paper on http://www.vetcancercare.com/),
"It is believed that the tumor forms when a foreign agent infiltrates the Langerhans cells and stimulates unchecked proliferation. These tumor promoting agents are carried by ticks and other insects from dog to dog, and facilitate spreading of the agent causing cutaneous histiocytoma."
Histiocytoma, April 17. Tumor is pinker and less pronounced.
This makes sense, since foreign material from the French bulldog's fangs may have been introduced during the injury. And anyone who's had a child in daycare is familiar with the frequent fevers and colds toddlers suffer while their developing immune system adjusts to the outside world. This explains why histiocytomas are common in young dogs under two years of age.

Although histiocytomas are benign, Ms. Hiltner goes on to emphasize that a proper diagnosis is necessary, because "problems arise when malignant tumors disguise themselves as cutaneous histiocytoma and owners delay diagnosis and treatment."

Happily, Miss Roxy's histiocytoma resolved after a month or two, and she's as happy and beautiful as ever.

Further reading:

Disclaimer: This is a chronicle of our bulldog's healthcare experiences, and is not intended to give medical advice. It is best to have all health issues evaluated by a veterinarian.

©2012 Tammy Yee