Caption |
Mammary gland: there was, at the periphery of the solid mammary carcinoma, a dilated interlobular duct that was lined by a 5-10 cells-thick epithelium that often formed small secondary lumens. Myoepithelial differentiation was not identified in this duct. This lesion may represent invasion of an interlobular duct by the solid carcinoma, or may indicate in situ carcinoma in an interlobular duct adjancent to a mammary carcinoma. The formation of a relatively large number of secondary lumens, a feature that was not detected in the solid carcinoma, supports a diagnosis of in situ carcinoma. |