Cerebral metastasis - lung cancer
The patient went on to have a resection.
Sections of specimen B confirm metastatic carcinoma surrounded by brain tissue. The tumor cells are arranged in sheets with focal permeation into brain tissue. The tumor cells are immunoreactive for CK7. There is variable nuclear immunoreactivity for TTF1. CK20 immunoreactivity is also variable.
Final Diagnosis: metastatic carcinoma, consistent with metastatic non-small cell carcinoma of the pulmonary origin.