Evaluation of surgical margins required for complete excision of cutaneous mast cell tumors in dogs.
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.


METHODS
Prospective study.


METHODS
21 client-owned dogs with > or = 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 degrees, 90 degrees, 180 degrees, and 270 degrees. 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
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.
Simpson
Amelia M
AM
Department of Surgery, Donaldson-Atwood Cancer Clinic & Flaherty Comparative Oncology Laboratory, The Animal Medical Center, 510 E 62nd St, New York, NY 10021, USA.
Ludwig
Lori L
LL
Newman
Shelley J
SJ
Bergman
Philip J
PJ
Hottinger
Heidi A
HA
Patnaik
Amiya K
AK
D000818:Animals; D004283:Dog Diseases / Q000473:pathology / Q000601:surgery*; D004285:Dogs; D005260:Female; D008297:Male; D012515:Mast-Cell Sarcoma / Q000473:pathology / Q000601:surgery / Q000662:veterinary*; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000517:prevention & control / Q000662:veterinary; D009367:Neoplasm Staging / Q000662:veterinary; D011446:Prospective Studies; D012878:Skin Neoplasms / Q000473:pathology / Q000601:surgery / Q000662:veterinary*