ABSTRACT
We describe the cytological features of a malignant phyllodes tumor, in a 40-yr-old female, that metastasized to the forearm, and we correlate these findings with the criteria suggested by other authors for predicting the clinical and metastatic behavior of this tumor. The diagnosis of metastasis was based on fine-needle aspiration (FNA) cytology. One year prior, the patient had undergone mastectomy of the left breast for malignant phyllodes tumor, as proven by histopathology. The patient then presented with right forearm swelling, 1 yr later. FNA cytology was performed, and the diagnosis was metastatic malignant phyllodes tumor. Histologic review of the breast tumor revealed stromal overgrowth, which is the most important histologic criterion for predicting the metastatic behavior of malignant phyllodes tumor as reported by some authors.
