Historically, certain anatomical locations (e.g. inguinal, perineal, scrotal, preputial, and muzzle areas) have been associated with more malignant-acting (biologically aggressive)
tumors,1,3,5 but recent reports have challenged this dogma.6 Clinical staging (evaluation of regional lymph nodes, lymphoid organs, and bone marrow) is used to detect possible metastatic
mast cell disease.1 Information gathered from clinical staging and histologic grading is used to determine the optimal approach to treatment.
Treatment options include excision with wide surgical margins, chemotherapy, and radiation therapy, or some combination of
modalities, depending on the size, location, and malignant potential of the tumor.1
This case report was provided by Maria Vandis, DVM, and Joyce S. Knoll, VMD, PhD, DACVP, Department of Biomedical Sciences,
Cummings School of Veterinary Medicine,Tufts University, North Grafton, MA 01536.
1. Thamm DH, Vail DM. Mast cell tumors. In: Small animal clinical oncology. 3rd ed. Philadelphia, Pa: WB Saunders Co, 2001;261-266.
2. Meinkoth JH, Cowell RL. Recognition of basic cell types and criteria of malignancy. Vet Clin North Am Small Anim Pract 2002;32:1209-1235.
3. Gross TL, Ihrke PJ, Walder EJ, et al. Mast cell tumors. In: Skin diseases of the dog and cat. 2nd ed. Ames, Iowa: Blackwell Publishing, 2005:853-858.
4. Raskin RE. Skin and subcutaneous tissues. In: Atlas of canine and feline cytology. Philadelphia, Pa: WB Saunders Co, 2001;77-87.
5. Gieger TL, Theon AP, Werner JA, et al. Biologic behavior and prognostic factors for mast cell tumors of the canine muzzle:
24 cases (1990-2001). J Vet Intern Med 2003;17:687-692.
6. Sfiligoi G, Rassnick KM, Scarlett JM, et al. Outcome of dogs with mast cell tumors in the inguinal or perineal region versus
other cutaneous locations: 124 cases (1990-2001). J Am Vet Med Assoc 2005;226:1368-1374.