Abstract
A study was undertaken to evaluate the significance of oil-staining in sputum cytology.We utilized Oil-red-O and Papanicolaou's methods for staining, both of which were simultaneously performed on each pair of 3, 289 specimens. The materials were obtained from 1, 503 consecutive patients managed in our hospital for 20 months, since the beginning of 1984, and were divided into 4 groups according to the number of histiocytes containing red granules within the cytoplasm in Oil-red-O staining;among these, a'strongly fat-positive' group was defined for those with numerous fat-laden histiocytes scattered in clusters observed in low-power fields. Consequently, the'strongly fat-positive'group was highly correlated with positive-cytology or clinically evident lung cancer;'strongly fat-positive'was recognized in 71.1% of positive-cytology specimens v.s.10.7% of negative-cytology and 74.0% of specimens from lung cancer patients v.s.10 to 20% of those without cancer.It is noteworthy that more than 40% of the'strongly fat-positive'but negative-cytology specimens were associated with definite evidence of lung cancer.There was no significant relationship between the number of fat-laden histiocytes and histopathological type, grade of differentiation, or size and site of the neoplasm. Histological study of the surgical specimens suggested the origin of fat-laden histiocytes within the tumor tissue.Improved detection of lung cancer may be expected with the supplementary demonstration of fat-laden histiocytes with Oil-red-O staining in the practice of sputum cytology.
