[A case of tubular adenoma of the breast preoperatively suspected to be an advanced cancer].

A very rare case of a tubular adenoma of the breast is reported. The patient, 59-year-old woman, was admitted to hospital because of a large, left breast tumor. The tumor, 11 cm in diameter, was adhered to the surface skin. Because a malignancy was suspected, an incisional biopsy was first carried out. A pathologic examination revealed it to be a tubular adenoma, and a simple mastectomy was chosen as the operative procedure because a latent malignancy was not ruled out. The removed tumor was grossly cystic and a histological examination supported the finding that it was a non-malignant tubular adenoma.