Clinical evaluation of cytological diagnosis of nasopharyngeal malignancies.

Between 1970 and 1975 cytological examination was applied to the diagnosis of nasopharyngeal malignancies in a series of 216 consecutive patients who had either a tumour in the nasopharynx or clinical signs of nasopharyngeal carcinoma, or who were locally asymptomatic but had enlarged cervical lymph nodes. Smears were taken by introducing a small rough pad of compressed gauze through the mouth into the nasopharynx with an upward-angled forceps. In each case the cytological smear was taken immediately before biopsy; often, a lymph node was removed subsequently. When morphological diagnoses were doubtful and histological findings were at variance with positive cytological findings, the patients were reexamined clinically, and diagnosis was postponed. The case material was made up of 90 nasopharyngeal carcinomas, 24 lymphomas, one malignant melanoma, one adenoid cystic carcinoma and 100 patients without malignancies. Cytological findings from the first smear were positive in 77.8% of nasopharyngeal carcinomas, in 66.6% of lymphomas and in the cases of melanoma and adenoid cystic carcinoma. There were no false-positive results. When the nasopharyngeal carcinomas were subdivided into undifferentiated carcinomas of the nasopharyngeal type and squamous-cell carcinomas, cytological findings were positive in ,0% and 73%, respectively. Positivity of histological findings was distributed as follows: 91.7% for malignant lymphomas, 86.6% for undifferentiated carcinomas and 86.6% for squamous-cell carcinomas. With respect to clinical suspicion of malignancy, positive cytological findings were obtained in 50% of clinically occult cases and in 84.6% of patients with obvious malignancies; intermediate figures were found for clinically doubtful (64.3%) and for highly suspicious (77.8%) cases. Cyto-histological concordance was shown in 70% of cases; false-negative histological results were obtained in 7.8% and false-negative cytological results in 16.6% of cases. Combined cyto-histological positive results allowed diagnostic accuracy from the first samples in 94.4% of cases. Undifferentiated carcinoma appeared to be the malignancy most accessible to cytological diagnosis, with positive results ranging from 65% in clinically negative or doubtful cases to 84.5% in those with obvious tumours. Assessment of the cytology of the nasopharynx, using the new sampling method described herein, may be a useful diagnostic tool in nasopharyngeal maliganancies.