A case of ALK-positive lung cancer effectively diagnosed by cell block preparation

Background : ALK tyrosine kinase inhibitors are effective for the treatment of ALK-positive lung cancer, and should be used in personalized medicine for lung cancer. In the present study, we report a case of pulmonary adenocarcinoma diagnosed from a pleural fluid cytological sample, that was demonstrated to be positive for ALK using a cell block sample. Case : The patient was a 58-year-old woman. At about one year after the start of chemotherapy for lung adenocarcinoma, she developed brain metastasis, adrenal metastasis, and pleural effusion. Cytological and cell block samples were prepared from the pleural fluid. The rapid cytological sample showed aggregated atypical cells with enlarged eccentric nuclei containing clear nucleoli. The cell block sample also showed similar atypical cells, which were identified to be positive for ALK by immunohistochemistry and FISH. Conclusions : Cell block samples can be stored for a long time, and can also be used for genetic testing. Combined rapid cytology allows rapid and appropriate processing of residual samples and contributes to clinical diagnoses.