Lymphangiosarcoma with systemic metastases in a Japanese domestic cat

A 4-year-2-month-old female Japanese domestic cat was diagnosed with lymphangiosarcoma through tissue biopsy of an amputated leg. Two months later, the cat was euthanized, and postmortem findings revealed edema, and bruising at the caudal region of the trunk, pulmonary hemorrhage, pulmonary nodules and mediastinal lymphadenopathy. Microscopically, neoplastic tissues were observed in the dermis and subcutis of the trunk, lung, mediastinal lymph nodes, diaphragm, omentum and mesentery. The tumor cells were spindle to polygonal-shaped with nuclear pleomorphism aligning along pre-existing collagen bundles and forming irregular vascular channels in which the erythrocytes were rarely observed. These cells were immunopositive for vimentin, von Willebrand factor and CD31. Based on the histopathological and immunohistochemical features, the neoplasia was diagnosed as lymphangiosarcoma with systemic metastases.     

Establishment of cell line and in vivo mouse model of canine Langerhans cell histiocytosis

A cell line named FB‐LCH01, derived from a dog diagnosed with Langerhans cell histiocytosis (LCH), was established and characterized. FB‐LCH01 had C‐shaped nucleoli, characterized by modal chromosome aberrations. The original tumour cells as well as established FB‐LCH01 cells were immunopositive for human leukocyte antigen‐DR, Iba‐1 and E‐cadherin, and immunonegative for CD163 and CD204, suggesting Langerhans cell origin. Furthermore, the characteristics of FB‐LCH01 were compared with those of two canine histiocytic sarcoma cell lines (PWC‐HS01 and FCR‐HS02) established previously. Expression of E‐cadherin was detected only in FB‐LCH01, but not in PWC‐HS01 and FCR‐HS02. All (n = 9) the severe combined immunodeficiency mice inoculated with the FB‐LCH01 cells developed subcutaneous tumour masses after 3 weeks. Eight of nine mice also developed metastatic lesions in the lymph nodes (8/8; 100%), lung (5/8; 62.5%), stomach (5/8; 62.5%), heart (4/8; 50%), pancreas (4/8; 50%), kidney (3/8; 37.5%), skin (3/8; 37.5%) and bone marrow (1/8; 12.5%). Tumour cells were pleomorphic and round‐ to polygonal‐shaped with prominent anisocytosis and anisokaryosis. The xenotransplanted tumour cells maintained the immunohistochemical features of the original tumour with persistent E‐cadherin expression at injection site and some visceral organs. In conclusion, the established cell line as well as the mice xenotransplant model in this study reflect the nature of canine LCH and may serve as promising models for investigating the patho‐tumorigenesis and therapy of the disease.