Endometrial polyps in the cat. Retrospective study

Introduction and aim - Endometrial polyps (PE) are tumor-like lesions frequently reported in domestic carnivores. Clinical and pathological features were investigated in the cat through a retrospective study. Materials and methods - On 162 female cats, signaling, clinical history, symptoms, macroscopic and microscopic findings of the genital tract were analyzed, also using immunohistochemistry for the detection of the antigens: proliferating cell nuclear antigen (PCNA) and smooth muscle actin (SMA). Results and discussions - The PE was diagnosed in ten 11 +/- 4-year-old cats, confirming the prevalence of the disease in entire and elderly animals. Eight cats had a regular reproductive history. Five showed symptoms comparable to or superimposed on a picture of pyometra. The clinical diagnosis was possible only for large PEs by transabdominal palpation or ultrasound. Macroscopically, PEs measured 1-2 cm in diameter and exceptionally reached the size of 10 cm. PEs were multiple, sessile or pedunculated, usually localized in both uterine horns. The lesion was always associated with cystic endometrial hyperplasia (IEC). The microscopic structure of PE was fibroglandular with a stroma sometimes infiltrated and hemorrhagic. In two cases, there were focal precancerous areas, confirmed by the increased expression of PCNA. In two cases, there were areas of stromal smooth muscle metaplasia, as confirmed by the coexpression of SMA and PCNA.This study confirms that PE originates from IEC and, despite its hyperplastic nature, it is potentially precancerous.