Fine-needle aspiration cytology diagnosis of metastatic nonhaematological neoplasms of the breast: a series of seven cases.

Metastatic neoplasms of the breast are rare. Mammary metastases as the initial presentation are even more infrequent and can simulate a primary malignancy clinically and radiologically. Recognition of metastatic tumors in the breast is important because it would prevent unnecessary mutilating surgery and would lead to appropriate treatment of the primary tumor. There is a broad variety of cytological appearances reported about primary tumors and few reports about secondary breast malignancies, specially diagnosed by FNAC. This study was carried out to examine the clinical and cytomorphologic features of metastatic breast tumors found in 12 de Octubre University Hospital during a period of 20 years. It confirms the utility of FNAC and describes findings that can help in the differential diagnosis that sometimes can be very difficult. Seven cases of nonhematological metastatic neoplasms of the breast were identified from the files of the Department of Pathology of the 12 de Octubre University Hospital from a total of 64,000 aspirates. We included only metastatic tumors from extramammary nonhematological neoplasms. There were nine cases of hematological metastatic neoplasm that were excluded. They were diagnosed with FNAC and confirmed by histopathology, with at least three years of follow up. The breast lump was the first manifestation of malignancy in one case of synovial sarcoma. The other six cases had been previously diagnosed of cancer. These included one malignant melanoma, one alveolar rhabdomyosarcoma, one mixed müllerian tumor, one medullary carcinoma of thyroid, one colonic adenocarcinoma, and one gastric adenocarcinoma. The period of time between primary tumor and metastases ranged from one month to eight years. An accurate cytologic diagnosis was made in all the cases. Immunocytochemistry was available but diagnosis could be made with cytomorphology alone in the seven cases. Fine-needle aspiration cytology is an excellent first line diagnostic modality that is particularly informative when clinical previous data are known. If metastatic disease is suspected, the material obtained by FNAC may provide a definitive diagnosis and prevent open surgical biopsy or mastectomy. We concur with previous reports that FNAC is a reliable, rapid, secure, and cost-effective approach to the diagnosis of palpable metastatic breast tumors.