Histopathologic Patterns of Triple-Negative Breast Cancer in Makurdi, North-Central Nigeria

Abstract: - Background: Triple-negative breast cancer (TNBC), defined by the absence of estrogen receptor (ER), progesterone receptor (PR), and HER2 expression, is an aggressive breast cancer subtype associated with poor prognosis and limited targeted therapy. TNBC prevalence is disproportionately high among women of African ancestry, yet regional histopathologic data remain limited in North-Central Nigeria. Objective: To determine the histopathologic patterns and immunohistochemical profiles of TNBC in Makurdi, North-Central Nigeria. Methods: A retrospective descriptive study of invasive ductal carcinoma (IDC) cases diagnosed between 2021–2024 at Benue State University Teaching Hospital. Only histologically confirmed TNBC cases with complete ER, PR, and HER2 status were included. Tumours were classified and graded using WHO 2019 criteria and Nottingham grading. Data on patient demographics, histologic subtype, and tumour grade were analysed using descriptive statistics. Results: Among 290 IDC cases, 179 (61.6%) were TNBC. Patients’ ages ranged 20–89 years, with peak incidence in the 50–59 years’ group (32.1%). TNBC predominated in middle-aged women (40–59 years). Most tumours were high-grade invasive ductal carcinoma of no special type (NST), with a minority showing special histologic subtypes. Immunohistochemistry revealed ER negativity in 58.3%, PR negativity in 60.3%, and HER2 negativity in 66.2% of cases. Conclusion: TNBC constitutes a substantial proportion of breast cancer in Makurdi, affecting predominantly middle-aged women, with high-grade invasive ductal carcinoma as the dominant histologic pattern. These findings underscore the need for region-specific diagnostic strategies, early detection programs, and tailored management protocols to address the high burden of TNBC in North-Central Nigeria