Pathological assessment of microinvasive carcinoma of the breast

Background Microinvasive breast cancer (T1mi) is considered as a precursor of invasive cancer developing from ductal carcinoma in situ (DCIS). This study discussed the clinicopathological and immunohistochemical features of T1mi by comparing those of ductal carcinoma in situ (Tis) and T1a to assess the nature and causes of the progression of Tis into invasive cancer.