Histiocytoma in dogs is usually treated by surgical removal of the tumor. These benign tumors often disappear on their own in a few weeks, though scratching and biting may cause the tumor to become infected, necessitating the decision to remove the tumor.
A histiocytoma originates in the immune cells of a dog's skin tissue. A histiocytoma is indicated by the presence of a small, round growth on the surface of the skin. Young dogs are most often affected by histiocytoma. These tumors are often found on the edges of the ears, the head or the limbs. Histiocytomas grow rapidly in the early stages. This rapid growth may result in the tumor becoming ulcerated and infected.
Due to their similarity to malignant tumors, histiocytomas are regularly examined by a veterinarian. Blood tests, urinalysis, an electrolyte panel and a physical exam can rule out malignancy. Definitive diagnosis is done by a veterinary pathologist. The pathologist exams cells from a skin sample from the tumor that has been removed by needle aspiration or removal of a portion of the tumor. Examination under the microscope reveals several distinct differences in cells with histioctyoma. Although it may be possible for a dog to transmit histiocytoma to another dog, the disease cannot be passed on to humans.