Evaluation of Mast Cells in Dermal versus Subcutaneous Hemangiomas and Hemangiosarcomas in Dogs

Abstract

This study investigated the role of mast cells in canine cutaneous vascular tumors, and is the first such study to distin-guish between tumors arising in the dermis versus the subcutis. Mast cell numbers in canine cutaneous hemangiomas (HA) and hemangiosarcomas (HSA) were evaluated to identify a relationship between mast cells, tumor type (HA, HSA), histologic location (dermis, subcutis) and tumor recurrence. One hundred and sixty-seven biopsies from 148 dogs were evaluated. Using only one biopsy from each dog, mast cell counts (MCC) for each tumor (n = 148) were ob-tained by averaging the number of mast cells counted in ten 400× fields. A significant difference in mean MCC was found only between tumor types, with HA having more mast cells than HSA (4.2 ± 4.2 vs. 2.2 ± 2.6; p < 0.001). No significant difference in mean MCC existed between tumors that recurred and those that did not. There was no differ-ence in recurrence rate between tumor type or histologic location. Our results indicate that benign HA contain more mast cells than malignant endothelial cell tumors, regardless of histologic location; whether this is a cause or effect re-lationship remains to be determined.