Granulosa Cell Tumour in a Spayed Cat With Ovarian Remnant Syndrome and Hyperestrogenaemia Without Estrus Signs

Granulosa cell tumour (GCT) is the most common primary ovarian neoplasm in cats and may arise from residual ovarian tissue following incomplete spay procedures.

To describe the surgical management of a GCT identified in the setting of Ovarian Remnant Syndrome (ORS) in a spayed cat with hyperestrogenaemia without estrus signs, and to assess the potential utility of serum estradiol as an adjunct for diagnosis and postoperative monitoring.

A 6-year-old female domestic shorthair cat, reportedly spayed, presented with a 2-week history of weight gain and abdominal distension. Diagnostic imaging and cytology suggested a large neuroendocrine tumour occupying the abdominal cavity. Exploratory laparotomy was performed, and the abdominal mass along with one hepatic nodule was resected.

Histopathology confirmed GCT in the abdominal mass with hepatic metastasis. A preoperative serum sample collected at initial presentation and assayed after receipt of the histopathology report showed markedly increased estradiol. Although clinical signs improved after surgery, the cat re-presented 4 weeks later with abdominal distension and severe anaemia; imaging revealed progression of hepatic lesions, and the patient died 5 weeks after surgery.

This case highlights that GCT can occur in the setting of ORS without estrus signs, despite marked hyperestrogenaemia. Ovarian remnants may undergo neoplastic transformation and cause life-threatening disease, even in the absence of estrus signs. Serum estradiol may be a valuable marker for diagnosis, treatment response, and recurrence monitoring in feline GCT.