Malignant Myoepithelioma of the Breast Clinically and Histologically Masquerading as Angiosarcoma: Cytological Findings and Review of the Literature.

Background: Malignant myoepithelioma of the breast is an exceptionally rare, aggressive tumor with a diverse morphology, the cytological features of which have only occasionally been described.

Case Report: Our case comprises a 74-year-old woman who was admitted to our hospital with an erythematous, inflammatory-like mass of her left breast with nipple ulceration, and clinically fixed to the chest wall. The woman underwent fine-needle aspiration and biopsy. The aspirates consisted mainly of loose aggregates of large, highly pleomorphic, polygonal epithelioid cells as well as aggregates of spindle cells with prominent, easily detectable mitoses and single, multinucleated pleomorphic giant cells. The cytological diagnosis was consistent with high-grade malignancy. Histologically, the lesion consisted broadly of eosinophilic epithelioid cells with globoid cytoplasm in a reticulated, angiomatoid pattern and of spindle (sarcomatoid) cells in a storiform pattern, highly suspicious of angiosarcoma. A final diagnosis of malignant myoepithelioma was made.

Conclusion: We present the cytological findings in comparison with the unusual histological features of a malignant myoepithelioma of the breast. A high degree of suspicion with a keen eye for morphological details coupled with relevant immunohistochemistry will aid in arriving at the correct diagnosis.