We describe four cases of feline progressive histiocytosis (FPH) including three females (one intact, two spayed) and one castrated male cat, with a mean age of 5.95 years at diagnosis. Masses were found under the skin of head, lip, neck, and vulva. Histologically, proliferative round cells had ovoid nuclei, foamy eosinophilic cytoplasm, distinct cytoplasmic processes, and mitotic figures. Immunohistochemically, all cases were positive for Iba1 and MHC II (Dako). One case showed cytoplasmic positive staining for E-cadherin. To the best of our knowledge, this is the first documented report of FPH in Korea.

Two 11-year-old cats, female Korean shorthair cat and male Siamese cat, with abdominal distention were presented to the local animal hospitals. Radiographic and ultrasonographic examinations revealed moderate to severe splenomegaly in both cats. In Korean shorthair cat, multiple masses were also existed on the anal and facial skin. Surgically excised whole spleens of two cats were requested for histopathologic examination. Histopathologically, numerous neoplastic round cells with cytoplasmic fine granules were widely infiltrated in the splenic parenchyma. The cytoplasmic granules were metachromatic on toluidine blue staining. These splenic masses were diagnosed as splenic mast cell tumors. Among them, Korean shorthair cat was remained healthy for at least 1 year after splenectomy. Because of no visiting of owner, we were only able to know the information for Siamese cat until 10 months after the splenectomy. To our best knowledge, this is the first detail case reports for splenic mast cell tumors in cats in Korea.

A 13-year-old castrated male Maltese dog was presented to a local animal hospital with an oral hemorrhage. An intraoral examination revealed an irregular proliferated lobular mass at the right side of the maxillary gingiva and hard palate. A surgically excised mass was requested for a histopathology examination. Histopathologically, the neoplastic foci were composed of biphasic morphologic patterns, such as primitive mesenchymal tissue and mature or immature cartilage tissue. Immunohistochemically, most of the neoplastic cells forming cartilaginous islands tested positive for S-100; the surrounding mesenchymal cells tested positive for vimentin. This paper describes a rare case of mesenchymal chondrosarcoma in the maxillary gingiva of a Maltese dog.

We describe 7 cases of splenic smooth muscle tumors in dogs. Histopathological and immunohistochemical analysis revealed that 6 cases were diagnosed as splenic leiomyosarcoma and 1 case as leiomyoma. All dogs underwent splenectomy without chemotherapy, and one of them was euthanized 2 months after surgery because of hepatic metastasis. Of the remaining 6 dogs, 5 died in the postoperative period and only one dog survived > 4 years. The median survival of the 6 dogs was 16.9 months. To the best of our knowledge, this is the first detailed study on splenic smooth muscle tumors in dogs in Korea.