Fibrosarcoma

Fibrosarcoma (fibroblastic sarcoma) is a malignant tumor derived from fibrous connective tissue and characterized by immature proliferating fibroblasts or undifferentiated anaplastic spindle cells.Usually in males ages 30 to 40. Originates in fibrous tissues of the bone. Invades long or flat bones such as femur, tibia, and mandible. It also involves periosteum and overlying muscle.

Pathology
The tumor may present different degrees of differentiation: low grade (differentiated), intermediate malignancy and high malignancy (anaplastic). Depending on this differentiation, tumor cells may resemble mature fibroblasts (spindle-shaped), secreting collagen, with rare mitoses. These cells are arranged in short fascicles which split and merge, giving the appearance of "fish bone" known as a herringbone pattern. Poorly differentiated tumors consist in more atypical cells, pleomorphic, giant cells, multinucleated, numerous atypical mitoses and reduced collagen production. Presence of immature blood vessels (sarcomatous vessels lacking endothelial cells) favors the bloodstream metastasizing.

Fibrosarcoma in dogs and cats
Fibrosarcoma occurs most frequently in the mouth in dogs. The tumor is locally invasive, and recurs often following surgery. Radiation therapy and chemotherapy are also used in treatment. Fibrosarcoma is also a rare bone tumor in dogs.

In cats, fibrosarcoma occurs on the skin. It is also the most common vaccine-associated sarcoma.

Experimental Laser Procedure
Autologous patient specific tumor antigen response: apSTAR Veterinary Cancer Laser: The use of a laser combined with a polymer has been shown to enhance tumor immunity and improve the rate of primary and metastatic tumor regression in laboratory models of tumors. Veterinary Cancer Therapeutics, LLC, a division of IMULAN BioTherapeutics, LLC, has recently started examining the use of this laser device, termed apSTAR, for dogs and cats with fibrosarcoma and other tumor types