Event Abstract Back to Event Diffuse oral ulcerations as the only presentation of secondary syphilis: a case report Marco Cabras1*, Alessio Gambino1, Luigi Chiusa1, Dora Karimi1, Roberto Broccoletti1 and Paolo Giacomo Arduino1 1 University of Turin, Department of Surgical Sciences, Oral Medicine Section, Italy Aim. Syphilis is a sexually transmitted disease caused by an anaerobic helical bacterial species, Treponema pallidum. It is classified into four stages: primary, secondary, latent, and tertiary. Oral lesions are mainly correlated to secondary syphilis, even though oral signs can appear at any stage. Due to the large variety of clinical appearance, for whom it is usually defined as “the great imitator”, diagnosis can be delayed, especially if no skin or genital involvement is detected. Aim of this study is to present a peculiar case of a male patient with just diffuse oral ulcerations, without cutaneous or genital involvement, leading to a conclusive diagnosis of secondary syphilis. Materials and Methods. In July 2018, a 43-year-old patient was referred to the Oral Medicine Section of CIR-Dental School, University of Turin, for painful diffuse oral ulcers, arisen four months before on the lower lip and tongue, for which he was treated with antifungal and antiviral therapy to no avail. Anamnesis revealed smoke habit (10 cigarettes per day), with no history of drug intake or aphthous recurrent stomatitis. Conventional oral examination (COE) revealed a wide ulcerated lesion with fibrinous borders on top of a swollen internal surface of the lower lip; an exuberant mucous plate on the right side of the tongue, a smaller white patch on the tongue tip, and a non-homogeneous white-and-red plaque on the posterior left side of the tongue. Although aphthous and drug-related ulcers could be easily excluded through anamnesis, due to the nonspecific clinical appearance, a biopsy with direct immunofluorescence (DIF) was performed on the injured right side of the tongue, in order to assess the occurrence of an underlying bullous or granulomatous disease. Complete blood count (CBC), anti-desmoglein 1 and 3 antibodies and serum angiotensin converting enzyme (s-ACE) were also required at the time of the first investigation. Between biopsy and pathological examination, the patient was treated with systemic corticosteroids (75 mg of prednisone daily for the first five days, followed by 50 mg daily for the next seven days, and 25 mg daily for the last ten days), and chlorhexidine 0.20% mouthrinse (Curasept® three times a day for three weeks). Three weeks later, the patient reported a mild improvement of symptoms, whereas COE still showed no complete remission nor blatant decrease in diameter of lips and tongue lesions. Moreover, the specimen analysis did not display morphological elements suggestive of bullous or granulomatous disease: DIF was negative, whereas hematoxylin and eosin staining revealed hyperkeratosis, acanthosis and spongiosis with a mild lymphoplasmacellular infiltrate and exocytosis of neutrophil granulocytes. PAS and GROCOTT stainings highlighted sporadic fungal ifae within the epithelium. CBC showed mild neutrophilia (10.61^10.9/L; range 1.50-1.80) and monocytosis (1.45 ^10.9/L; range 0.20-1.00), with normal s-ACE (26.1; range 8-53 µl) and no anti-desmoglein 1 and 3 antibodies (<5U/ml for both). The clinical hypothesis of an underlying autoimmune disease was then put aside, and a new recollection of anamnestic data was carried out, suspecting an infectious etiology for such unusual lesions: questioned on risky behaviors, the patient admitted to having unprotected sex with his male partner in the last year. Treponema Pallidum, HCV and HIV tests were immediately required: no HCV and HIV antibodies were detected, whereas VDRL was suggestive of active disease (1:16), with highly positive TPPA (>1:10240; range <1:80) and CLIA for Treponema Antibodies (>70.00; range <0.9). Results. Although the patient does not recollect a genital or oral chancre-like lesion in the previous months or years, nor displays any skin or genital concurrent signs, a diagnosis of oral secondary syphilis was formulated. He has been referred to the Infectious Diseases Unit of the “Ospedale Amedeo di Savoia”, Turin, for proper evaluation and treatment. Discussion. The diagnosis of syphilis is based on a combination of full sexual history, clinical examination, serological tests and histological examination, if carried out with special stains. In our case, anamnesis played a key role in correcting the algorithm of differential diagnosis. Questions regarding risky behaviors such as unprotected sex should always be included in the recollection of anamnestic data, bearing in mind that patients will provide an honest and reliable answer to such intimate queries only if they perceive to be engaged in a trusting relationship with their oral health providers. In light of the most recent epidemiological evidences, which show an increasing incidence of syphilis in Europe, it is important for dental practitioners and oral physicians to consider syphilis in patients with atypical oral lesions/ulcerations, especially on those otherwise healthy individuals who appear to be unresponsive to topical or systemic corticosteroids.