Invasive breast carcinoma of no special type with medullary pattern: A case report at a tertiary facility in Tanzania

Key Clinical Message Describes a rare form of invasive breast cancer of no special type. Not a distinct morphological subtype. Characterized by dense lymphoid infiltrate, syncytial growth, pushing borders, and cells with high‐grade nuclei. Clinically aggressive but carries a better prognosis than other more frequent invasive breast carcinomas. Invasive breast carcinoma of no special type with medullary pattern (BCNST‐MP) is a rare form of breast tumor, accounting for less than 5% of all invasive breast carcinomas. Its diagnosis is based on histologic criteria. Historically, this tumor was known as medullary carcinoma. Poor morphological reproducibility led to re‐classification. Despite having an aggressive biological behavior, these tumors usually carry a better prognosis compared with other more frequent forms of invasive breast carcinomas. Herein, we present a case of BCNST‐MP in a 58‐year‐old African female, successfully treated in our institution through chemo‐radiation, hormonal therapy and surgery. A: Photograph showing a gross specimen of invasive breast carcinoma, NST with medullary pattern demonstrating well circumscribed margins and greyish‐white cut surface resembling benign breast lesion. B: Histopathology of the tumour made up of a syncytial sheets of large pleomorphic cells without glandular formation, the adjacent stroma demonstrate prominent tumour infiltrating lymphocytes.