Medullary Breast Carcinoma

Excerpt

Medullary carcinoma is a rare and distinct subgroup of breast carcinomas accounting for less than 5% of all invasive breast cancers.

This unique histologic subtype has very strict criteria for diagnosis, including complete circumscription, the syncytial growth pattern of at least 75% of the tumor, intermediate to high nuclear grade, an associated diffuse lymphocytic infiltrate and a lack of intraductal components or glandular differentiation.

The 2012 World Health Organization updated the classification of medullary carcinoma under an umbrella term of “carcinomas with medullary features,” which also includes atypical medullary carcinoma and invasive carcinoma of no special type with medullary features.

Medullary carcinoma has a favorable prognosis in spite of its poorly differentiated histologic features and basal-like phenotype.