ラットにおける自然発生腹腔内血管肉腫の肺転移

This short communication describes a spontaneous hemangiosarcoma within the abdomen, which appeared to have originated from the prostate gland area with infiltration, and that metastasized to the lungs in a 46-week-old male Sprague-Dawley rat. At necropsy, a 90 mm × 60 mm × 50 mm dark cystic neoplastic mass was present in the abdomen and the lung lobes had multiple dark cystic neoplastic structures. The abdominal mass was necrotic with a few peripheral areas of plump oval cells and frond-like structures lined by spindle-shaped cells. The lung neoplastic cysts were filled with blood and there were foci of plump oval cells within and peripheral to the cysts, as well as multiple small clusters throughout the lung parenchyma. Neoplastic cells of the abdominal mass and lung cysts stained positively for von Willebrand Factor by immunohistochemistry, indicating a vascular endothelial cell origin and consistent with a diagnosis of hemangiosarcoma. The lung hemangiosarcomas were considered metastases from the abdominal hemangiosarcoma based on their similar cellular morphology and multiple foci throughout the lung lobes.