Cutaneous Mast Cell Tumour in Dog: A Case Study

Mast cell tumors (MCTs) are very common in dogs, less common in cats, and uncommon to rare in other species. The biological behavior of MCT is highly variable; some tumors are benign whereas others have aggressive growth and metastasize. Recent studies revealed the role of stem cell receptor (KIT) in the etiology of canine MCTs. KIT is normally expressed on hematopoietic cells and mast cells. Present communication describes a mast cell tumour with fast growing and recurring nature. Histopathologically tumour comprises of diffuse sheets of uniform dyscohesive round cells separated by incomplete fibrous septae. These cells have scant to moderate cytoplasm and round to oval nucleus with slightly opened up chromatin. Immunohistochemically diffuse patterns of KIT expression were seen in tumour cells with granular labeling of mast cells.