Rapid frozen section diagnosis of pituitary tumors.

From 751 patients with suspected pituitary tumor, 2,354 frozen sections were prepared for histological identification of the tissue and determination of the resection margins after selective adenoma removal. The accuracy of the method was determined by comparison of the frozen section diagnoses with the diagnoses of permanent sections of the same tissue. The overall accuracy was 83. I%. The reasons for incorrect diagnoses in frozen section were analyzed retrospectively. Prevailing causes were spurious lesions resulting from problems in processing the extremely small specimens, and regressive transformations of the tissue leading to alterations of the tissue structure. Despite the rather low accuracy rate, we would consider frozen section diagnosis of pituitary tumors as a valuable aid for the surgeon. Other morphological methods are not as accurate in the determination of the resection margins in selective microsurgery. If applied by an experienced team, the method can be recommended.