Spontaneous occurrence of multiple trichoepithelioma in a Jin-do dog

진도개에서 자연 발생한 다발성 모낭 상피종

A 10-year-old Korean native female Jin-do dog revealed two growing subcutaneous masses measuring 7.0 ${\times}$ 7.0 ${\times}$ 2.5 cm and 5.0 ${\times}$ 4.0 ${\times}$ 2.0 cm in the left shoulder and lower part of chest, respectively. Grossly tumor masses were well-circumscribed and exhibited ulcerated surface and purulent exudate on the cut surface. Histologically tumor masses were characterized by cystic structures some of which were fused together. Although the cells of cyst wall differentiated to those similar to infundibulum, isthmus, inferior segment of hair follicles, respectively, the most cyst wall consisted of cells similar to infundibulum The luminal content of cysts depended on the cells of cysts; infundibulum-like cyst contained lamellar keratin, isthmus-like cyst was amorphous keratin, and inferior segment-like cyst had shadow cells. From these results, these tumor masses were diagnosed as multiple trichoepithelioma. To our knowledge, this is the first report of canine multiple trichoepthelioma in a dog in Korea.