Qualitative and quantitative cytomorphologic features of primary anaplastic lymphoma kinase-positive lung cancer.

OBJECTIVE: Anaplastic lymphoma kinase (ALK) positive (+) lung cancers are predictive for response to crizotinib and alectinib. There are many cases of lung cancer in which surgery cannot be performed, and such cases require diagnosis by cytologic specimen or biopsy. Estimating ALK (+) lung cancer from cytomorphology would allow molecular testing to proceed without the waste of a small amount of specimen. The purpose of this study was to assess whether qualitative and quantitative cytomorphologic features are sufficient for distinguishing primary ALK (+) from ALK (-) lung cancer.

METHODS: We examined eight qualitative cytomorphologic parameters and three quantitative nuclear morphometric parameters in 17 cases of primary ALK (+) lung cancer, diagnosed by fluorescence in situ hybridization (FISH) using histologic specimens, and in 41 cases of ALK (-) lung cancer. Quantitative nuclear morphometric parameters were analyzed by a computer-assisted image analysis system.

RESULTS: In ALK (+) lung cancer three qualitative parameters (signet ring cells, nuclear grooves, and single type nucleoli) and two quantitative parameters (large nuclear area and irregular nuclear shape) were observed in significantly higher proportions. However, in ALK (-) lung cancer, one qualitative parameter (unclear and multiple type nucleoli) was seen significantly more often.

CONCLUSIONS: These results show that the cytomorphologic features of signet ring cells, nuclear grooves, and nucleoli shape can help to triage a small amount of cytologic and biopsy specimens for appropriate molecular testing of primary ALK (+) lung cancer. This article is protected by copyright. All rights reserved.