What type of lesions are caused by Feline Infectious Peritonitis (FIP)?

Feline Infectious Peritonitis (FIP) is characterized by a complex pathological process, primarily involving immune-mediated responses to the feline coronavirus. The disease typically results in a form of vasculitis that leads to the presence of effusive (wet) or noneffusive (dry) forms of FIP, both of which display specific types of lesions.

In the case of effusive FIP, the resultant lesions often consist of suppurative and granulomatous inflammation, combined with the accumulation of modified transudate in body cavities. Granulomas are aggregates of macrophages and are typically surrounded by a rim of lymphocytes, which signifies a chronic immune response. This immune-mediated reaction contributes to the characteristic fluid accumulation and necrotic tissue that can be observed in affected animals.

In contrast, the other types of lesions described in the other options do not accurately represent the pathology observed with FIP. For instance, necrotizing lesions may be associated with other infectious diseases but not specifically FIP. Hemorrhagic lesions are not typical of FIP pathology; instead, they are more indicative of other conditions such as trauma or certain viral infections. Cystic lesions similarly do not have a connection with FIP and suggest different underlying processes