Immunohistochemical and Clinicopathological Characteristics of Invasive Breast Carcinoma in Nigeria.

ABSTRACT

Objectives: We aimed to study the immunohistochemical and clinicopathological characteristics of invasive breast carcinoma among Nigerian women. Methods: We conducted a retrospective assessment of female patients diagnosed with breast carcinoma at a tertiary hospital in Nigeria between 2012 and 2019. Archived pathology request forms and processed specimens (tissue blocks and slides) were used as source data in addition to the patients' demographic and other relevant data. Results: Reports pertaining to 113 patients were assessed. Their age range was 30 to 80 years (mean = 52.1±12.1 years). Breast carcinoma was most common in patients aged 40 to 49 years (32.7%), closely followed by those aged 50 to 59 years (30.1%). Invasive ductal carcinoma was the most common histopathological subtype (94.7%). Nottingham grade III and grade II breast carcinoma accounted for 41.6% and 40.7% of the cases, respectively. Mastectomy specimens formed 68.1% of the samples. The most common tumor size (75.9%) was > 5cm (mean = 6.8±3.2cm), consistent with the most common staging of T3 (46.0%). The most common lymph node involvement was N1 (56.6%). Immunohistochemical assessment of these tumors with estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2 (HER-2) biomarkers expressed positivity of 36.3%, 28.3%, and 41.6%, respectively. These tumors were immunohistochemically classified into luminal A (16.8%), luminal B (20.4%), HER-2 enriched (20.4%), and triple-negative (42.5%) subtypes. Conclusions: The most common immunohistochemical subtype of invasive breast carcinoma among this sample of Nigerian women was the triple-negative subtype, similar to the finding among African Americans.