Solid Tumour Section

Classification Invasive ductal carcinoma is a heterogeneous group with many different subtypes, some of them extremely rare. Each of these variants is associated with another pathological presentation and with a different prognosis compared to invasive ductal carcinoma of no special type (NST). As shown in Figure 1, some of the most important subclassifications are: Medullary carcinoma: younger age, association with BRCA1 mutation, 1-5% of breast carcinomas, rarely lymph node metastases, bad prognosis Metaplastic carcinoma: <1% of breast carcinomas, association with BRCA1 mutation, bad prognosis Mucinous/colloid carcinoma: older age, 1-6% of breast carcinomas, better prognosis Inverted papillary carcinoma: 1% of all breast carcinomas, better prognosis, striking lymphovascular invasion Tubular carcinoma: younger age, about 5% of breast carcinomas, excellent prognosis Cribriform carcinoma: younger age, good prognosis.