A case of nodular fasciitis occurring in the left breast region in a middle-aged woman is reported. Fine-needle aspiration cytology showed pleomorphic spindle cells with occasional multinucleated giant cells, superficially mimicking sarcomatous neoplasms. The diagnosis of nodular fasciitis was established by core needle biopsy. In order to obviate unnecessary surgical resection of this benign self-limited lesion, the initial cytologic evaluation is essential to rule out malignant mesenchymal tumors arising from the breast.
