Fine needle aspiration cytology of mammary duct ectasia - Report of a casewith novel cytologic and immunocytochemical findings

BACKGROUND: Mammary duct ectasia (MDE), or periductal mastitis, is a well-d efined clinical entity with a characteristic histopathologic appearance on breast biopsy specimens. However, the cytologic features of MDE have been d escribed only recently in the cytopathology literature, and fine needle asp iration (FNA) cytologic findings are based mainly on a small number of case reports in the English-language literature. Therefore, awareness of this e ntity and recognition of its cytomorphologic features could aid in a more a ccurate diagnosis. We report the novel cytologic and immunocytochemical fin dings on a case of MDE that was confirmed by histologic examination on a su bsequent biopsy. CASE: We report the findings of breast FNA cytology in a 50-year-old female with a mammographically and clinically suspicious lesion. Cytology display ed a paucicellular aspirate, typified by a few scattered, cohesive clusters of ductal epithelial cells with mild nuclear atypia and distinct, peripher ally located myoepithelial cells. Intermingled within the ductal elements w ere numerous polygonal cells with abundant, finely vacuolated cytoplasm tha t were immunoreactive for macrophage specific antibody, CD68. The backgroun d consisted of a variable number of foam cells and negligible amount of blo od. CONCLUSION: The current case of MDE demonstrates cytomorphologic features t hat may pose diagnostic problems, particularly as a consequence of variable cytologic atypia this entity may present on FNA cytology. This diagnostic difficulty is compounded because of the abnormal mammographic and suspiciou s clinical findings that may be associated with MDE. CD68 immunoreactivity is a useful ancillary tool to verify the histiocytic, rather than epithelia l and potentially neoplastic, nature of multivacuolated cells. To the best of our knowledge, there has been no prior reported case of MDE in the Engli sh-language literature studied utilizing CD68 antibody. This case report em phasizes that MDE is a heterogeneous entity with diverse cytomorphologic fe atures. FNA cytology in conjunction with immunocytochemistry might permit a ccurate classification in the proper clinical setting.