Feulgen staining applied to nuclear histomorphometry with ImageJ in canine mammary carcinoma subtypes

Abstract

Histomorphometry is an important tool in the diagnosis and prognosis of breast cancer, enabling the quantification of microscopic features related to tumor aggressiveness. This study aimed to standardize the Feulgen staining method for nuclear morphometric analysis and to compare nuclear measurements among different subtypes of canine mammary carcinoma. Histological slides with tissue microarray (TMA) sections from tubulopapillary carcinoma (TPC), complex carcinoma (CC), and solid carcinoma (SC) diagnoses were stained using the Feulgen method. Five random fields per TMA sample were photographed at 400× magnification, and nuclear morphometry was performed using ImageJ software with the Threshold tool. The SC subtype showed significantly larger nuclear area (85.40 µm² ± 0.3159) and nuclear perimeter (48.33 µm ± 0.1217) compared to the TPC and CC subtypes (P < 0.0001). These results indicate that SC, a high-grade malignant neoplasm, presents greater nuclear dimensions. Nuclear area and perimeter proved to be more reliable parameters for comparisons between different subtypes, while circularity was useful in differentiating malignancy grades within the same subtype. Feulgen staining demonstrated high efficiency for nuclear histomorphometry, allowing precise nuclear delimitation and reducing subjectivity in quantitative evaluation. Keywords: dog; histochemical staining; malignancy grade; neoplasm; nuclear morphometry. Keywords: Carcinoma, dog, neoplasms, nuclear morphology.