Which clinical sign might suggest a visceral hemangiosarcoma?

A sudden collapse or weakness is a significant clinical sign that may suggest a visceral hemangiosarcoma. This particular type of cancer commonly affects the spleen and can lead to the rupture of a tumor, causing internal bleeding. When this happens, animals may experience significant blood loss, which can result in rapid onset of weakness, lethargy, or collapse due to hypovolemic shock.

The critical aspect of hemangiosarcoma is its propensity for sudden and severe clinical presentations, often without prior warning. Due to the nature of the disease and its effects on the circulatory system, the sudden onset of weakness serves as an indicator that warrants urgent evaluation and intervention.