Equine placental mixed germ cell tumor with metastasis to the foal.

This research article discusses a unique case in which a placental tumor in a mare also resulted in the development of a metastatic germ cell tumor in the foal the mare carried. The foal was eventually euthanized due to poor prognosis.

Inspection of Placenta and Foal

• The research begins with the examination of a placenta from an embryo transfer-recipient mare and its live foal. The placenta was found to be covered in multifocal masses ranging from less than 1cm to 14cm in diameter.
• The foal, previously carried by the mare, displayed symptoms of lethargy, ataxia (lack of muscle control), and urination problems at 52 days of age. Due to the grim prognosis, the foal was euthanized.
• Upon performing a necropsy on the euthanized foal, it was discovered that its liver was covered in irregular pale nodules. Its lumbar vertebrae and other bones had several lytic lesions, which are areas of bone damage or destruction.

Cell Examination and Diagnosis

• On examining the placenta and the foal’s liver, four distinct populations of neoplastic (cancerous) cells were identified. These included a variety of cells such as spindle cells, tall columnar and transitional epithelial cell populations, and an undifferentiated polygonal cell population.
• Interestingly, similar populations and patterns of these cells were found both in the placenta and the foal’s liver, suggesting the foal’s condition might have resulted from the placental condition.
• The observation concluded that the abnormality observed in the placenta was a mixed germ cell tumor. In the foal, the masses were diagnosed as a metastatic mixed germ cell tumor, indicating that the tumor cells in the placenta had spread to the foal causing it to develop similar tumors.