Erosive and annular lesions of the gastric mucosa: Not negligible signs of Treponema pallidum infection

The interesting article about gastric syphilis recently published in your journal prompted us to make some observations.¹ Several studies published in the last year have turned the spotlight on gastric syphilis.^1-3 Although stomach involvement is estimated at only 1% of syphilis patients, mainly in the secondary stage of the disease, the incidence of T. pallidum infection is increasing worldwide²; therefore, we can also expect an increase in gastrointestinal syphilis.

We agree with the authors about the importance of considering syphilis in the differential diagnoses of gastrointestinal diseases when the patient complains of non-specific symptoms (abdominal pain, nausea, diarrhea, anorexia), physical examination detects epigastric tenderness, and endoscopy shows erosions and ulcerations, especially in an annular shape.² The annular lesion morphology may raise suspicion of syphilis not only in the stomach but especially in the skin. In our experience, cutaneous lesions with annular morphology, with both widespread and localized distribution, are among the most common atypical presentations of secondary syphilis.⁴ The ancient definition of syphilis as the ‘great imitator’ based on its wide variety of manifestations is still actual since unusual manifestations can be found in up to 25% of the cases, especially in the secondary stage.⁴ As Iwamuro et al. described, the annular morphology of the lesions seems to be an early morphological pattern of gastric syphilis followed by erosions and ulcerations.² In the skin, the annular shape of the lesions is often associated with syphilis reinfection⁵; it is not known if it applies also to the mucosal lesions. Indeed, previous syphilis episodes may alter the clinical/laboratory presentations of a new T. pallidum infection, which happens with more insidious cutaneous/mucosal manifestations.⁵ However, the heterogeneity of the clinical features in syphilis may be related to the multiple circulating genovariants of T. pallidum, characterized by different virulence and tissue tropism.⁴

It would be interesting to know if the patient described by Itoh et al. has had a previous T. pallidum infection and if he was screened for other sexually transmitted diseases besides HIV that can be acquired with syphilis, such as hepatitis B and C, Chlamydia trachomatis and Neisseria gonorrhoeae.

In conclusion, gastric syphilis can clinically and histologically simulate other gastrointestinal diseases, including lymphoproliferative diseases, invasive carcinomas, tuberculosis, and Crohn's disease. Definitive diagnosis is made by PCR testing for T. pallidum in paraffin-embedded tissues or immunohistochemical staining for T. pallidum-specific antigens. The diagnostic suspicion of gastric syphilis should be considered primarily in patients with risk factors for sexually transmitted infections who present with nonspecific gastric lesions, especially in young patients having a gastric tumor incidence below 10%.³

Given the increase in syphilis incidence in recent years, clinicians should be well-trained to recognize its atypical manifestations that may occur on the skin, mucous membranes and internal organs.

Giulia Ciccarese: Conceptualization; investigation; writing – review and editing; supervision. Antonio Facciorusso: Supervision. Vanessa De Pace: Validation; supervision. Francesco Drago: Supervision; writing – review and editing.

The authors did not receive funding for this work.

The authors have stated explicitly that there are no conflicts of interest in connection with this article.

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