ACTH-secreting carcinoma of the breast.

We report a case of ACTH-secreting carcinoma of the breast. Membrane-bound secretory granules were seen within the cancer cells electron microscopically. Cytoplasmic granules reacting immunochemically to anti-ACTH antisera were seen on light microscopy. Breast cancers have been shown to secrete calcitonin, parathyroid hormone, human chorionic gonadotropin, and norepinephrine in addition to ACTH. This suggests either the presence of neuroendocrine cells in the breast as a source of such neoplasms, as in the lung, or genomic derepression during neoplastic transformation.