An ovarian fibrosarcoma in a Rabbit

Background and Aim Fibrosarcoma is a deadly tumor rarely derived from fibrous connective tissue. This malignant tumor grows slowly, and its main characteristics are the proliferation of immature fibroblasts or undifferentiated anaplastic spindle cells. The etiology of this tumor is unknown, while rarely leads to metastasis. A 3.5-year-old rabbit was referred to the veterinary clinic due to anorexia. After the examination, an ultrasound of the abdominal area was performed, which showed evidence of a tumor. The case was subsequently referred to radiography to investigate for any metastasis. After that, surgery was performed to remove the tumor mass from the ovaries and uterus, which weighed 120 grams. After taking a tissue sample and fixating it in a 10% buffered formalin buffer solution, it was referred to the pathology laboratory. The tissue was processed, sliced into 5-micron sections, and stained with Hematoxylin and Eosin as well as Masson's trichrome stainings. Our findings showed malignant changes such as spindle-shaped cells with unusual nuclei and mitotic figures, random growth patterns, and collagen fibers in all directions, in addition to the infiltration of inflammatory cells. Finally, the sample was diagnosed as fibrosarcoma. It should be noticed that regarding this tumor type, surgery is the recommended approach. However, if surgery is not possible, radiotherapy and chemotherapy can also be used. Same as this case, even after successful surgery, the animal should be monitored due to the possibility of recurrence. It should be noted that after 7 months, the animal's condition was reported to be good.