Cytologic diagnosis and grading of ductal carcinoma in situ

BACKGROUND. Fine-needle aspiration cytology plays an important role in the preoperative diagnosis of palpable masses as well as impalpable lesions tha t can only be sampled by stereotactic or ultrasound techniques. A further r efinement of cytologic diagnosis would be the ability to distinguish among the different types of ductal carcinoma in situ (DCIS) also between in situ and invasive malignant disease. METHODS. Sixty-six cases of histologically proven, pure DCIS (39 high grade , 12 cribriform, and 15 low/intermediate grade) with a preoperative cytolog y report of carcinoma were retrieved from our files. All the cytology (wet- fixed and air-dried smears) was reviewed by G.M., and the histology section s were reviewed by G.T. Seven cytologic features, including cellularity, ce ll dissociation, nuclear size, cell uniformity, nucleoli, nuclear margins, and chromatin pattern, were assigned scores from 1 to 3. The presence of ca lcium, necrosis, and foamy macrophages was recorded. Cell clusters were exa mined for evidence of a cribriform pattern. Fat and stromal fragments were closely checked for infiltration by tumor cells. RESULTS. The cell type was predominantly large and pleomorphic in high grad e DCIS, whereas it was mainly small and well differentiated in the cribrifo rm and low grade types. Calcium and necrosis were seen in most high grade l esions and less frequently in the cribriform and low grade ones. Macrophage s were more common in high grade and cribriform DCIS than in low/intermedia te grade DCIS. Cribriform spaces were noted only in cribriform DCIS. Stroma l and fat infiltration by tumor cells was not present in any of the aspirat es. Myoepithelial cells were rarely seen. CONCLUSIONS. The presence of pleomorphic carcinoma cells, calcium, necrosis , and macrophages in the aspirate accompanied by "casting" calcification on the mammogram is virtually diagnostic of high grade (comedo) DCIS. Cribrif orm DCIS shows features of low grade carcinoma with a typical cribriform pa ttern of punched-out holes in the cell clusters. Low/intermediate grade DCI S has no particular distinguishing features. (C) 1999 American Cancer Socie ty.