Extraskeletal osteosarcomas (EOSs) are rare tumors that arise in various soft-tissue sites (e.g., gastrointestinal tract, subcutaneous tissue, spleen, liver, skin, kidney, urinary bladder, muscle, thyroid gland, eye, and mammary glands). Soft-tissue osteosarcomas (STOs) occur in older dogs with no sex predilection; beagles and rottweilers are at higher risk. Mammary gland osteosarcomas (MGOs) occur in older females; mixed-breed dogs, German shepherd dogs, and miniature poodles are at higher risk. The median survival time for cases with STO was 26 days, and the major cause of death was local recurrence (92%). The median survival time for cases with MGO was 90 days, and the major cause of death was pulmonary metastasis (62.5%).
A six-month-old Neopolitan mastiff presented for a rapidly growing cervical mass. Undifferentiated sarcoma was diagnosed at post mortem based on histopathology and immunohistochemistry. Metastases to mediastinum, pleura, lungs, liver, kidneys, omentum, mesentery, and multiple lymph nodes were present. Soft-tissue sarcomas are reported infrequently in children and young dogs. The cell of origin often is difficult to determine due to poor differentiation and rapid growth of these neoplasms.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.