“…In 1978, Chapel found that less than half (42.7%) of patients with PS he diagnosed presented typical single, indurated chancres with regional lymphadenopathy, suggesting that the “classic” chancre may be the “atypical” lesions [ 15 ]. However, beyond many case report [ 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ] and narrative review [ 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ] syphilis manifestations, very few studies and/or case series including more than five cases with atypical syphilis manifestations have been published in the English literature during the past 20 years [ 32 , 33 , 34 , 35 , 36 , 37 , 38 ] ( Table 4 ). Cases of atypical primary syphilis misdiagnosed as pharyngeal lymphoma, tongue cancer, and other types of oral squamous cell carcinomas have been described [ 39 , 40 , 41 ]; however, the secondary stage of the disease, given the possible involvement of the whole skin area and of other organs, is the one that is most prone to misdiagnosis like palmoplantar psoriasis, psoriasis vulgaris, erythema multiforme, cutaneous lymphoma, and granulomatous diseases of the skin (annular granuloma, sarcoidosis).…”