Cytologic findings of spindle cell ductal carcinoma in situ of the breast -: A case report

Background Ductal carcinoma in situ (DUS), spindle cell type, is a rare and recently recognized entity in the breast. While the histologic features have been described in detail, no cytologic descriptions exist. We describe the cytologic and corresponding histologic findings in a case of spindle cell DUS. Case A 35-year-old woman underwent fine needle aspiration (FNA) of a 1.5-cm, palpable mass. The aspirate showed predominantly clusters and a smaller population of single cells in a necrotic background. The cells were mostly spindled, with a minor population of epithelioid cells. They had a high nuclear/cytoplasmic ratio, with hyperchromatic and pleomorphic nuclei that contained prominent nucleoli, altogether diagnostic of malignancy. Given the biphasic cell composition, a diagnosis of metaplastic carcinoma was favored and excision recommended; it showed spindle cell DCIS. Conclusion The cytologic features of spindle cell DCIS and metaplastic spindle cell carcinoma are similar and almost indistinguishable. Despite its rarity, spindle cell DCIS should be considered in the differential diagnosis of biphasic and spindle cell lesions in the breast.