[Value of cytokeratin 7 and 20 for the diagnosis of cerebral metastases of adenocarcinoma: study of 78 cases].

OBJECTIVE: histological features of metastasis are not always specific of the origin. The usefulness of cytokeratin 7 and 20 (CK7 and CK20) in cerebral metastases from an adenocarcinoma was studied in a series of 78 patients. RESULTS: metastases from lung adenocarcinoma showed a CK7+/CK20- pattern in 79% of cases, CK7+/CK20+ in 19% and CK7-/CK20- in 2%. When observed, positivity for cytokeratin 20 was generally focal or weak. Breast adenocarcinoma metastases were CK7+/CK20- in 71% of cases and CK7-/CK20- in 29%. Less differentiated tumours were usually negative for both cytokeratins. Metastases by colonic adenocarcinoma were CK7-/CK20+ in 100% of cases. Cytokeratins 7 and 20 are useful to distinguish lung from colonic metastatic carcinoma. In case of double positivity, a more intense CK7 expression is rather suggestive of a lung origin. CONCLUSION: these results might modify paraclinic investigations in search of the primitive tumor.