Histiocytic sarcoma

Histiocytic sarcoma in a Labrador Retriever crossbreed. A large, irregular and lardaceous mass, with extensive necrotic areas can be seen occupying the mediastinum. This mass was associated with abundant hydrothorax and bilateral lung collapse. The tumour had already metastasized to the liver and spleen. Several, small, pale, umbilicated metastatic nodules can also be seen in the parietal pleura.