Histomorphological and Immunohistochemical Profile of Malignant Breast Lesions in a Tertiary Care Center of Central India: A Cross-Sectional Study.

INTRODUCTION: Breast carcinoma is a heterogeneous malignancy with variable histomorphological patterns and immunohistochemical profiles. Evaluation of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2/neu) expression provides important prognostic and predictive information for treatment planning. Ki-67 was not evaluated in the present study; therefore, the reported immunohistochemical subgroups were based only on ER, PR, and HER2/neu expression. This study aimed to assess the histomorphological and immunohistochemical profile of malignant breast lesions in a tertiary care center in Central India. METHODS: This cross-sectional observational study included 84 patients with histopathologically confirmed malignant breast lesions. Tumors were classified according to standard histopathological criteria and graded using the Nottingham modification of the Bloom-Richardson system. Immunohistochemistry was performed for ER, PR, and HER2/neu. Molecular subtypes were assigned based on ER, PR, and HER2/neu expression. RESULTS: The most common age group was 41-50 years (n = 39, 46.4%). Invasive ductal carcinoma, not otherwise specified, accounted for 95.2% (80/84) of cases. Grade III tumors were observed in 58.3% (49/84), and lymph node metastasis was present in 58.3% (49/84). ER, PR, and HER2/neu positivity were observed in 59.5%, 53.6%, and 29.8% of cases, respectively. The hormone receptor (HR)-positive/HER2-negative subgroup was the most common (59.5%), followed by HR-positive/HER2-positive (17.9%), HR-negative/HER2-positive (11.9%), and triple-negative (10.7%) subgroups. On descriptive analysis, HR positivity decreased with increasing tumor grade and nodal positivity, whereas HER2/neu positivity increased. CONCLUSION: Histopathological evaluation combined with ER, PR, and HER2/neu immunohistochemistry provides important information for tumor classification, prognostic assessment, and therapeutic decision-making in breast carcinoma. Routine integrated reporting is essential for individualized management of malignant breast lesions.