Two reports recently published by Diagnostic Cytopathology, 1,2 illustrating the cytologic features of a number of metastatic tumors to the breast, stressed the importance of preoperative fine-needle aspiration cytology (FNAC) in the management of patients, to avoid unnecessary surgery and to ensure appropriate chemo-or radiation therapy. 2 In a 12-yr period during which we performed a total number of 2,500 breast FNAC for benign and malignant mammary lesions, we observed 3 cases of metastatic cancer to the breast, originating from the colon, liver, and kidney, respectively.The first case was an FNAC of a right breast lump in a 66-yr-old female, known in our Department for a 10-yr history of colonic pT2, G2 adenocarcinoma with subsequent (6 yr later) solitary lung metastasis and late (8 yr later) thoracic skin metastasis. The cytological specimens were characterized by a necrotic background and tubular structures of neoplastic epithelial cells, with oval nuclei and finely granular elongated, mucin-free cytoplasms ( Fig. 1a,b). The cytologic diagnosis was of metastatic colonic adenocarcinoma to the breast. The patient continued chemotherapy.The second case concerned a 75-yr-old female, known to have a long-standing cirrhosis (HCVϩ), which caused, 1 yr later, a hemoperitoneum for the rupture of a superficial nodule of hepatocellular carcinoma. Cytological FNAC smears obtained from an upper-external right breast quadrant nodule contained sheets and trabeculae of epithelial cells showing polygonal, finely granular, eosinophilic cytoplasm, and large, hyperchromatic central nuclei, with eosinophilic macronucleolus/i (Fig. 2a). A diagnosis of metastatic hepatocellular carcinoma was made. The lumpectomy confirmed metastatic hepatocellular carcinoma to the breast (Fig. 2b).The specimens relating to the third patient were characterized by irregular clusters of monomorphic cells with low nuclear/cytoplasmic ratio, round nuclei, finely granular chromatin, a single prominent macronucleolus, and foamy and finely vacuolated pale cytoplasm (Fig. 3a). Dispersed single cells and many naked nuclei were present in the background. A diagnosis of malignant tumor cells, meta-static, was made, and a clear-cell carcinoma originating from the kidney was suggested. The patient, a 72-yr-old female, underwent a simple mastectomy, and histological Fig. 1. a: Tubular structure of neoplastic epithelial cells, with oval nuclei and finely granular elongated, mucin-free cytoplasm (Papanicolaou stain, ϫ400). b: Glandular structures with the same cytological appearance of the clot inclusion from FNAC (hematoxylin-eosin stain, ϫ400).Fig. 2. a: Nest of malignant epithelial cells with polygonal, finely granular, eosinophilic cytoplasm and large, hyperchromatic central nuclei, with eosinophilic macronucleoli (Papanicolaou stain, ϫ400). b: Trabecular proliferation of neoplastic hepatocytes (hematoxylin-eosin stain, ϫ400).
