Croatia’s First Experiences in Cytological Diagnosis of High-Grade Ductal Carcinoma in Situ of the Breast: Case Reports and a Review of Literature

Cases here presented are also first Croatia’s experiences in the cytological diagnosis of breast ductal carcinoma in situ (DCIS). The first patient was a 64-year-old woman, by imaging methods with a wide area of suspect microcalcifications in the left breast lower medial quadrant and abundant, dense, yellow-greyish discharge of the same mammilla and second was a 65-year-old woman with an equivocal lesion in left breast lower lateral quadrant. Morphological findings of both aspirates and nipple discharge from the first patient were practically the same - moderately to highly cellular, with 3D solid aggregates, monolayer sheets and many scattered single clearly malignant cells of large - mainly >5x the diameter of an erythrocyte, round-to-ovaloid, manifestly irregular nuclei, dark blue, polymorphous, often multiple (macro)nucleoli, irregular nuclear outlines and dense, more basophilic, mostly scant cytoplasms arranged in syncytium–like structures. “Dirty” background was overfull of comedo necrosis and dark grayish, sharp, irregular microcalcifications. Cytological diagnosis in both cases was DCIS, high-grade, comedo type. Histopathologically first tumor was big, 6 cm large, estimated as comedo carcinoma with microinvasion focuses not bigger than 1 mm, but without signs of angioinvasion, while the second tumor was smaller, 0.6 cm with wide ducts fully with large polymorphic malignant epithelial cells, central comedo necrosis, cancerisation of some lobules but with the intact basement membrane. It was pure high-grade DCIS, comedo type. Presented cases completely reflect to date knowledge about cytological diagnostic of high-grade DCIS; include necessary morphological criteria - highgrade nuclear atypia, an abundance of comedo necrosis and microcalcifications, confirm our limitation in the presumption of invasion status with large lesion extent, but also prove that cytology is the unquestionably reliable in breast morphological diagnostic, even in such sophisticated and demanding pathological issue like DCIS.