Histiocytomas are benign, fast-growing, raised, hairless skin tumors found on the extremities, head, ears, and neck. Histiocytomas account for 3 to 14% of skin tumors occurring in the dog. Typically these lesions are round and less than three cm in diameter. These tumors occur most commonly in young dogs. Boxers, Dachshunds, Cocker spaniels, Great Danes, Shetland sheepdogs and Bull terriers are especially susceptible to histiocytomas. Often these tumors will resolve spontaneously within three months and may be multiple. The clinical course may be protracted when dealing with multiple nodules, with new nodules forming while others regress. Those tumors that do not resolve, become ulcerated, infected, or puritic (itchy) and are easily removed in their entirety surgically. Metastasis to the lymph nodes has rarely been reported but has been seen most commonly in the Shar-Peis.


References:

Risbon, Rebecca VMD, Criag Clifford, DVM, MS and Katherine Skorupski DVM. “An Overview of Canine Histiocytic Disorders”. Veterinary Medicine. July 2007. pp. 464-479.