Immunohistochemical markers of sweat gland tumors

Using immunoperoxidase methods, normal sweat glands, 44 benign and 4 malignant sweat gland tumors were tested for the presence of carcinoembryonic antigen (CEA), pregnancy-specific-B1-glycoprotein (SP1) and actin (ACT). CEA and SP1 stained the secretory and duct-lining cells of normal eccrine glands. Among benign tumors, 74% were positive for CEA and 44% for SP1. The staining reaction was found mainly in luminal secretions and surrounding cells. Staining by SP1 was reduced, but not suppressed, after absorption with the purified antigen. ACT was found in myoepithelial cells of the secretory tract of normal glands and in basal cells of all cases of hidradenoma papilliferum. Only 3 sweat gland carcinomas reacted for CEA. In a malignant chondroid syringoma, no ACT-positive cells were seen in the myxochondroid stroma. The potential value of CEA, SP1 and ACT in the diagnosis of sweat gland tumors is discussed.