Unusual presentation of granulocytic sarcoma in the breast: A case report and review of the literature

This is a case of granulocytic sarcoma presenting as bilateral breast masse s in a 40-yr-old woman with concurrent unsuspected chronic myeloid leukemia diagnosed by fine-needle aspiration. The granulocytic differentiation was recognized on Diff-Quik-stained cytology smears and confirmed rapidly on fl ow cytometry on the same day. The breast has been reported to be an uncommo n site for granulocytic sarcoma. We Sound that 38.8% of granulocytic sarcom as diagnosed by fine-needle aspiration in the English-language literature o ccurred in the breast. In the absence of clinical history or hematological abnormality, granulocytic sarcoma may be misdiagnosed, depending on the deg ree of myeloid differentiation present within the tumor. The differential d iagnosis includes large-cell non-Hodgkin's lymphoma, lobular carcinoma of t he breast, undifferentiated carcinoma, malignant melanoma, extramedullary h emopoeisis and inflammation. The key morphological features and useful anci llary tests are discussed. (C) 2001 Wiley-Liss,Inc.