Abstract
Objective—To determine whether neoplastic mast cells extended into tissue 1, 2, or 3 cm laterally or deeper than 1 fascial plane from the visible edge of cutaneous mast cell tumors (MCTs) in dogs.
Design—Prospective study.
Animals—21 client-owned dogs with ≥ 1 cutaneous MCT.
Procedures—After preparation for surgery, each dog's skin was marked 1, 2, and 3 cm from the tumor edge at 0°, 90°, 180°, and 270°. At each 3-cm mark, deep fascia was exposed and sutured to the skin; the tumor was excised in routine fashion and fixed in formalin. Tumors were graded; margins were examined histologically for neoplastic mast cells.
Results—23 cutaneous MCTs in 21 dogs were included in this study. Fifteen (65%) tumors were located on the trunk, 5 (22%) on the hind limbs, and 3 (13%) on the head and neck. There were 3 (13%) grade-I and 20 (87%) grade-II tumors. All grade-I tumors were completely excised at all margins. Seventy-five percent of the grade-II tumors were completely excised at the 1- cm margin, and 100% were completely excised at the 2-cm margin. Two grade-II MCTs located on the hind limbs of dogs were excised with a complete but close (within 1 mm) deep margin.
Conclusions and Clinical Relevance—Results suggest that a 2-cm lateral margin and a deep margin of 1 fascial plane appear to be adequate for complete excision of grade-I and -II MCTs in dogs. (J Am Vet Med Assoc 2004;224:236–240)