Cytomorphometry of large cell carcinoma of the lung

A computerized morphometry system was used to evaluate criteria for the cytologic diagnosis of large cell carcinoma (LCC) and poorly differentiated adenocarcinoma of the lung. There were 143 cells measured in six cases of LCC (five sputums and one bronchial washing) and 61 cells in four cases of adenocarcinoma (all sputum samples). Cellular and nuclear areas were significantly larger in adenocarcinoma whereas nucleolar area was greater in LCC, producing a higher nucleolar/nuclear area ratio in LCC. Cellular and nuclear form factors were smaller in LCC while the minor axis was longer in adenocarcinoma, resulting in a smaller axial ratio in adenocarcinoma. These data indicate that adenocarcinoma cells are larger and have a more rounded shape and less nucleolar material, as compared to the smaller, more ellipsoid and convoluted cells of LCC, which have more nucleolar area. A logistic regression identified cellular area, nucleolar/nuclear area ratio and cellular and nuclear form factors as significant contributors to the discrimination of LCC from adenocarcinoma, with a positive predictive value of 92%. Morphometry may therefore be helpful in the differential cytologic diagnosis of adenocarcinoma and LCC.