Intraoperative cytology of lymph nodes and lymphoid lesions.

Cytologic preparations from lymph nodes and lymphoid lesions in other tissues permit accurate intraoperative diagnosis of a number of lesions that are not commonly identifiable with certainty in conventional frozen sections. The clarity of cytologic detail in smears or imprints allows recognition of Hodgkin's and non-Hodgkin's lymphomas, certain metastatic tumors such as melanoma or oat cell carcinoma, and some nonneoplastic disorders, all of which must be diagnosed on the basis of cellular alterations. The characteristic cytologic features of these disorders are presented. Cytologic preparations also have proved valuable in evaluating lesions that usually can be diagnosed with frozen sections. For these lesions, the ability to see cytologic details provides greater diagnostic certainty. For some necrotic, calcified, or fatty specimens, smears or imprints are the only preparations possible. With alcohol fixation and rapid hematoxylin and eosin or Papanicolaou staining, the preparations are ready for examination within 2 minutes after the specimens are received. The cytologic presentations are essentially identical to those of aspiration biopsies. Use of each type of preparation helps develop and maintain the diagnostic skills needed for the other.