Some further features for differential diagnosis between squamous cell carcinomas and basal cell epitheliomas

Two further methods for the characterization of epidermal skin tumors are described: the antinuclear antibody (ANA) immunofluorescent test, which consists of indirect immunofluorescence with known high titer sera containing homogenous ANAs on epidermal skin tumors, and the ammoniacal-silver cytochemical method, which specifically stains nuclear histones. Squamous cell carcinomas (SCCs), basal cell epitheliomas (BCEs) as well as control specimens from normal skin and benign epidermal hyperplasias were studied. The ANA immunofluorescent test was positive for most SCCs, mixed SCC and basal cell carcinomas and metatypical BCEs. The ammoniacal-silver method gave a characteristic staining pattern shared among SCCs, mixed carcinomas and metatypical BCEs. BCEs, besides metatypical ones, were always negative by the ANA immunofluorescent test and the same applied for the control specimens. The ammoniacal-silver method gave a characteristic staining pattern for BCEs and control sections quite different from the staining pattern of the more aggressive forms of epidermal tumors. The two methods usually yielded parallel results.