Mast Cell Tumors: Update on Wound Healing

Cutaneous mast cell tumor (MCT) surgical sites may be at greater risk for wound healing complications; however, additional clinical studies are required. This study compared the healing of wounds from incompletely resected MCTs with those from incompletely resected cutaneous histiocytomas (CHs), which have a similar physical appearance and location to MCTs. Questionnaires were sent to veterinarians who requested information regarding cutaneous MCTs and CHs. Results from 242 dogs with CH (244 tumors) and 165 dogs with cutaneous MCT (185 tumors) showed that wound complications occurred in 20% of MCTs and 21% of CHs. Complications were more highly associated with tumors of the feet and/or those with a soft or baggy appearance, but tumor type did not matter. The sample size of high-grade MCTs was smaller than that for lower grades, but complication rates were similar to lower-grade MCTs and CHs.

Overall, the wound dehiscence rate (5.5% for MCTs; 3% for CHs) associated with these mass removals was higher than that reported for neutering studies (0.3%–2%), but a higher rate would be expected, as mass excision results in tissue deficit and damage to underlying tissue whereas a simple neutering incision does not. This paper did not support the hypothesis that incompletely resected MCTs have a higher complication rate; rather, MCT surgical wounds have similar complication rates as those for CH removal.

CommentaryMost of the MCTs in this study were grade I or II and relatively small in size (mean volume = 12 cm3, roughly 2.5 cm in diameter). However, we are most concerned about healing complications after excision of large, invasive, infiltrative MCTs, particularly when gross disease remains. These tumors were underrepresented, limiting the statistical power of the study. Therefore, while there is clear evidence that excision of routine MCTs is not associated with an increased risk for healing complications, this study cannot be used to predict the risk for healing complications in advanced-stage tumors. Presurgical treatment with histamine (H1 and H2) blockers is still recommended for all MCTs, and a discussion with the owner regarding the risk for healing complications is still advised for dogs with large, invasive MCTs.—Dennis Bailey, DVM, DACVIM (Oncology)

SourceMast cell tumor and cutaneous histiocytoma excision wound healing in general practice. Killick DR, Rowlands AM, Burrow RD, et al. J SMALL ANIM PRACT 52:469-475, 2011.