What are the histological features of vaccine-induced sarcomas in cats?

Vaccine-induced sarcomas in cats are characterized by specific histological features, which help in their diagnosis and understanding the nature of these tumors. The presence of spindled cells, often accompanied by necrosis and an infiltrate of inflammatory cells, is a defining aspect of these lesions.

Spindled cells refer to elongated cell shapes typical of connective tissue neoplasms, indicating a mesenchymal origin. Necrosis within the tumor points to a rapidly growing mass that outgrows its blood supply or has undergone some form of degenerative change, which is common in malignant tumors like vaccine-induced sarcomas. Additionally, an infiltrate of inflammatory cells suggests a response to the growth of the tumor, which can occur due to the body's immune reaction to the neoplasm.

These features assist veterinarians and pathologists in distinguishing vaccine-induced sarcomas from other types of tumors, which may have different cellular characteristics and patterns unless inflammatory cells are a predominant feature in those cases as well.

In the context of the other options, while well-differentiated cells might be seen in benign tumors, fibrous tissue growth might suggest a more fibromatous type of tumor that lacks the distinctive necrotic and inflammatory features prevalent in vaccine-induced sar