Syphilis is a re-emergent disease of great importance in medicine and stomatology. The polymorphic clinical and histopathologic aspects of secondary syphilis lead to biopsy. A 29-year-old man presented with a 2-week painless ulcer in the midline of the tongue, well delimited, bleeding, and rapidly evolving. The patient was a smoker and alcoholic. He denies a previous known history of comorbidities. An incisional biopsy was realized and revealed the presence of pseudoepitheliomatous hyperplasia, hyperparakeratosis, hydropic degeneration, spongiosis, blood vessels with turgid endothelium, chronic inflammatory infiltrate with predominance of plasma cells, and lymphocytic exocytosis. In addition, intense eosinophilia was observed in the amount of 38 units per field (×400). After histopathologic aspects and suspicion of syphilis, the screening test was made and revealed the titration of 1:128. Associating histopathologic, laboratory, and clinical findings, the diagnosis of secondary syphilis with presence of eosinophilia was confirmed, and the patient was referred to a reference unit for treatment.