Primary Cystic Lymphangioma of the Spleen in an Adult Dog.

Proliferative disorders of lymphatic origin in animals are mostly congenital or occur within the first few months of life. Involvement of internal organs is extremely infrequent. A seven-year-old entire female mixed-breed dog was presented with apathy and poor appetite. Abdominal ultrasonography revealed a focally enlarged spleen with an anechoic round lesion. Splenectomy was performed and pathological examination demonstrated a sponge-like, compressible tumour composed of endothelium-lined vascular cystic spaces filled with eosinophilic proteinaceous material lacking erythrocytes. Immunohistochemical stains showed that cyst-lining cells were strongly positive for CD31 and factor VIII and focally positive for lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1). Based on these findings, the lesion was identified as splenic cystic lymphangioma. To the best of our knowledge, this is the first description of solitary lymphangioma of the spleen in animals.

Primary Verocay Body-rich Epididymal Leiomyosarcoma in a Dog.

Leiomyosarcomas arising from paratesticular structures are rare. We report a case of epididymal sarcoma in an aged male Rottweiler that had histological features suggestive of neural origin but with muscular histogenesis confirmed by immunohistochemistry. Histologically, the lesion comprised a hypercellular neoplasm that had interlacing bundles of spindloid cells, prominent nuclear palisading and many Verocay bodies. Immunohistochemically, the neoplastic cells were strongly positive for smooth muscle markers but negative for neural markers, leading to the diagnosis of leiomyosarcoma. While the presence of nuclear palisading and Verocay bodies has been regarded as strong evidence for the diagnosis of schwannomas, the present report documents the presence of true Verocay bodies in a non-neuronal tumour. It also indicates that immunophenotyping is required for an accurate diagnosis when Verocay bodies are detected in sarcomatous or spindle cell tumours and provides prognostic information on this case. To the best of our knowledge, this is the first report of the presence of true Verocay bodies in a neoplasm other than a nerve sheath tumour in animals.