Ten years of respiratory cytopathology at Duke University Medical Center. III. The significance of inconclusive cytopathologic diagnoses during the years 1970 to 1974.

This paper reports on the significance of inconclusive cytopathologic diagnoses made on cytologic specimens from the lower respiratory tract of patients seen at the Duke University Medical Center during the years 1970 to 1974. During that period, a total of 9,892 cytopathologic specimens from the lower respiratory tract were processed. Conclusive cytopathologic diagnoses of cancer were made in 363 patients. In 218 additional patients, one or more inconclusive cytopathologic diagnoses were made. In 70 patients, a cytopathologic diagnosis of atypical metaplasia was made. In 28 of these 70 patients (40% of the group), this diagnosis was followed by a tissue confirmation of cancer. In the remaining 42 patients (60%), the follow-up studies revealed the presence of a variety of nonneoplastic diseases, usually inflammatory in origin. In these patients, various types of pneumonias constituted the most frequent type of disease. Another 135 patients had originally been given a cytopathologic diagnosis of "atypical cells suspicious for malignancy." In 92 (approximately 68%) of these patients, this suspicion of cancer was confirmed by tissue. In 43 patients (approximately 32%) no cancer was found. In this latter group of patients, the most common underlying disease process was also pneumonia.