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.