Morphologic changes in fibroadenoma of breast due to chickenpox: a case report with suspicious cytology in fine needle aspiration smears.

Background: Fibroadenomas with stromal giant cell reaction have been described in the literature, but cytologic atypia including giant cell reaction due to chickenpox giving rise to suspicious cytology has not been reported.

Case Report: A 25-year-old woman, recovering from chickenpox, presented with a 1.5 x 1.5-cm mass in the lower outer quadrant of her right breast. Fine needle aspiration smears showed sheets of benign ductal cells with overlapping myoepithelial cells and many bipolar bare nuclei. Cells showing nuclear enlargement, prominent nucleoli and multilobated or multinucleated giant cell formation occurred in separate sheets or dispersed among groups of benign ductal cells. Cytodiagnosis was suspicion for malignancy; excision biopsy was advised. Histopathologic examination showed fibroadenoma with evidence of epithelial hyperplasia, nuclear enlargement and multilobated giant cell formation. Atypical ductal cells, including the giant cells, were immunohistochemically positive for epithelial membrane antigen, estrogen receptor and progesterone receptor and negative for smooth muscle actin, indicating epithelial origin. Both cytologic and histologic specimens showed focal positive reaction with HSV-1 and HSV-2 antibodies. Ultrastructural examination of aspirated material revealed cytoplasmic viral particles with characteristic surface projections.

Conclusion: Herpes zoster virus can produce morphologic alteration mimicking a malignancy. Pathologists should be aware of these changes to avoid a false positive diagnosis.