不规则块状病变是乳腺浸润性导管癌。中央坚硬（硬癌）且因纤维结缔增生呈白色。肿瘤淡黄*色坏死区向周围乳腺组织浸润。这种肿瘤通常坚硬不活动。 The irregular mass lesion seen here is an infiltrating ductal carcinoma of breast. The center is very firm (scirrhous) and white because of the desmoplasia. There are areas of yellowish necrosis in the portions of neoplasm infiltrating into the surrounding breast. Such tumors appear very firm and non-mobile on physical exam.