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 that can only be sampled by stereotactic or ultrasound techniques. A further refinement 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 cytology 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 sections were reviewed by G.T. Seven cytologic features, including cellularity, cell dissociation, nuclear size, cell uniformity, nucleoli, nuclear margins, and chromatin pattern, were assigned scores from 1 to 3. The presence of calcium, necrosis, and foamy macrophages was recorded. Cell clusters were examined 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 grade DCIS, whereas it was mainly small and well differentiated in the cribriform and low grade types. Calcium and necrosis were seen in most high grade lesions and less frequently in the cribriform and low grade ones. Macrophages were more common in high grade and cribriform DCIS than in low/intermediate grade DCIS. Cribriform spaces were noted only in cribriform DCIS. Stromal and fat infiltration by tumor cells was not present in any of the aspirates. 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. Cribriform DCIS shows features of low grade carcinoma with a typical cribriform pattern of punched-out holes in the cell clusters. Low/intermediate grade DCIS has no particular distinguishing features. Cancer (Cancer Cytopathol) Copyright 1999 American Cancer Society.