Immunolocalization of keratin proteins in sweat gland tumours by the use of monoclonal antibody

A total of 34 cases (eccrine poroma: 2, cylindroma: 2, eccrine spiradenoma: 4, syringocystadenoma papilliferum: 1, hydroadenoma papilliferum: 1, clear cell hydroadenoma: 7, mixed tumour: 16) of sweat gland tumours of the skin were described in terms of immunohistochemical distribution of keratins using polyclonal anti-keratin antiserum (TK, detecting 41-56 KDa keratins) and monoclonal antibodies (KL1, 55-57 KDa; PKK1, 40, 45, 52.5 KDa). Keratin expression in eccrine poroma, spiradenoma and syringocystadenoma was similar to that in the ductal segment of normal sweat glands. Cylindroma showed usually slight staining for kertins. Tumour cells of hydroadenomas showed not so prominent staining for any of the keratins; however, histologically, tumour cells indicated marked variation, and the degree of keratin proteins also was different among these histological variants. Mixed tumours of the skin were strongly decorated with anti-keratin antibodies along the luminal surface cells of typical structures, while no staining occurred in outer side cells. Luminal tumour cells may be differentiated from secretory coil cells, whereas outer side cells may have a myoepithelial origin, as outer layer cells found in pleomorphic adenoma of salivary glands.