Cytochemistry of imprints from breast biopsies.

In order to investigate the cytoplasmic features of cells from benign and malignant breast lesions, a series of cytochemical reactions was applied to 117 sets of imprints made from breast biopsies. Alkaline phosphatase was present in all benign lesions except one but absent in 56% of the carcinomas. Lipids detected by the oil red O method were significantly more common in carcinomas but also present in a substantial number of benign lesions, making this difference of minor importance in diagnostic cytology. Carcinomas with a cytoplasmic lipid content stainable with oil red O and with moderate or marked sudanophilia had a significantly higher rate of axillary lymph node metastases, illustrating the prognostic value of the lipid-staining methods. Intracytoplasmic inclusions (ICI) detected by the periodic acid Schiff (PAS) method were found in 62% of the carcinomas and in only one benign lesion, making their presence of great diagnostic value. It is concluded that the application of certain cytochemical methods may improve the diagnostic accuracy of breast cytology.