Few studies on how to diagnose pulmonary neuroendocrine tumors through morphometric analysis have been reported. In this study, we measured and analyzed the characteristic parameters of pulmonary neuroendocrine tumors using an image analyzer to aid in diagnosis.

Sixteen cases of typical carcinoid tumor, 5 cases of atypical carcinoid tumor, 15 cases of small cell carcinoma, and 51 cases of large cell neuroendocrine carcinoma were analyzed. Using an image analyzer, we measured the nuclear area, perimeter, and the major and minor axes.

The mean nuclear area was 0.318±0.101 µm² in typical carcinoid tumors, 0.326±0.119 µm² in atypical carcinoid tumors, 0.314±0.107 µm² in small cell carcinomas, and 0.446±0.145 µm² in large cell neuroendocrine carcinomas. The mean nuclear circumference was 2.268±0.600 µm in typical carcinoid tumors, 2.408±0.680 µm in atypical carcinoid tumors, 2.158±0.438 µm in small cell carcinomas, and 3.247±1.276 µm in large cell neuroendocrine carcinomas. All parameters were useful in distinguishing large cell neuroendocrine carcinoma from other tumors (p=0.001) and in particular, nuclear circumference was the most effective (p=0.001).

Pulmonary neuroendocrine tumors showed nuclear morphology differences by subtype. Therefore, evaluation of quantitative nuclear parameters improves the accuracy and reliability of diagnosis.