Neoplasms with sweat gland differentiation express various glycoproteins of the carcinoembryonic antigen (CEA) family.

Carcinoembryonic antigen (CEA) is a well-established marker for sweat gland differentiation in adnexal neoplasms. In contrast to previous assumptions, CEA does not represent a single oncofetal antigen but comprises a family of homologous glycoproteins, i.e. the classical CEA-180, biliary glycoprotein (BGP), and non-specific crossreacting antigens (NCA). The aim of the study was to evaluate the distribution of the respective glycoproteins of the CEA family in sweat gland neoplasms, as compared to normal sweat glands. A panel of mono-specific antibodies was applied to a total of 83 samples of hyperplastic and cystic alterations of sweat glands, sweat gland neoplasms, and cutaneous metastases of different origin. Within a single group of neoplasms the immunohistochemical profile was rather consistent. Staining for both CEA-180 and NCA-90 indicated ductal differentiation of both eccrine and apocrine glands. Co-expression of CEA-180, NCA-90, and BGP was consistent with differentiation towards the secretory part of eccrine glands or the transitional portion of proximal ducts. Neoplasms with signs of apocrine secretion showed a preferential immunoreactivity for NCA-90 and BGP. In conclusion, a specification of the members of the CEA family may be of some value in the differential diagnosis of adnexal neoplasms, but not in the discrimination of sweat gland carcinoma from metastatic carcinoma.