Metastatic granulosa cell tumor in a mare.

The research article discusses the case of a Quarter Horse mare which showed non-weightbearing lameness and colic symptoms. The subsequent examinations and histologic study revealed the presence of a metastatic granulosa cell tumor, affecting several vital organs.

Clinical Presentation and Diagnosis

• The 5-year-old mare was initially brought in due to an acute non-weightbearing lameness of the left hind limb. However, no musculoskeletal abnormalities were found.
• After admission, the mare started showing signs of colic, a common digestive disorder in horses indicating abdominal pain or discomfort.
• An exploratory laparotomy was performed to identify any internal abnormalities. This procedure involves surgically opening the abdomen to visually examine the organs inside.
• During the laparotomy, the left ovary was found to be abnormally large. There were also masses discovered in the left sublumbar space, an area under the lumbar region of the spine, and a general infiltration of variably-sized masses in critical areas like the mesentery, omentum, liver, and spleen.

Post-mortem Examination and Findings

• The health condition of the mare continued to deteriorate, and it was decided to euthanatize the horse for humane reasons.
• Post-mortem examination, specifically histologic examination, was performed on several organs including the left ovary, left sublumbar and cranial thoracic lymph nodes, omentum, mesentery, liver, spleen, and lung.
• The histologic examination revealed the presence of granulosa cell tumor. Granulosa cell tumors (GCTs) are a type of ovarian tumor that originates from the granulosa cells. These cells are normally responsible for producing hormones in the ovaries.
• The distribution of the tumor in various organs confirmed that the horse had a metastatic form of granulosa cell tumor. Metastatic cancer is a type of cancer that has spread from the place where it first started (in this case, possibly the ovary) to other parts of the body.