This pericardial metastasis from an infiltrating ductal carcinoma primary shows predominantly nested morphology, consistent with ductal differentiation. However, in the lower portion of the field, sheets and cords of signet ring cells are present, indicating lobular differentiation. Immunohistochemical labeling for E-cadherin was diminished in the lobular areas. Other distant metastases in this case were exclusively lobular and lacked E-cadherin expression. For further details, please see the article by Wu and associates on page 1938 of this issue.

[Table of Contents]