Adenomyoepithelioma of the breast: report of a case initially examined by fine-needle aspiration.

This report describes the morphologic features of an adenomyoepithelioma of the breast that was first examined by fine-needle aspiration. On retrospective review of the cytology, the stromal elements of this adenomyoepithelioma showed extensive metachromasia on Diff-Quik stain, had elongated nuclei, and on Papanicolaou stain showed elongated, pale, wispy cytoplasm. Clusters of stromal cells were usually intimately associated with epithelial elements. While the main differential consideration, cystosarcoma phylloides, can show similar features, it may be possible to distinguish the two lesions in some instances.