A challenging diagnosis of syphilis in a patient with a testicular lump: a case report.

Authors

Francesca Pennati, Elisabetta Pedruzzi, Paolo Botti, Carla Scolari, Paola Zanotti, Maurizio Gulletta, Laert Zeneli, Deborha Pezzola, Alberto Matteelli

Published in

BMC infectious diseases. Jul 17, 2026. Epub Jul 17, 2026.

Abstract

Syphilis is a re-emerging sexually transmitted infection known for its heterogeneous clinical manifestations and ability to mimic neoplastic, inflammatory, and infectious diseases. Testicular involvement is rare and may radiologically resemble testicular cancer, frequently leading to unnecessary orchiectomy. We report a case of syphilitic orchitis initially suspected to be a testicular malignancy, highlighting the importance of including syphilis in the differential diagnosis of atypical testicular lesions.
A previously healthy 36-year-old man presented with a two-day history of dull right testicular pain associated with a palpable lump and a faint skin rash present for approximately two weeks. Ultrasound and contrast-enhanced ultrasound identified a 9-12 mm hypoechoic hypovascular intratesticular lesion suspicious for malignancy. Computed tomography showed no metastatic lesions, and serum tumor markers (LDH, HCG, AFP) were within normal ranges. A right orchifunicolectomy was performed. Histopathological examination revealed dense interstitial inflammatory infiltrates rich in plasma cells and lymphocytes without evidence of neoplasia. Immunohistochemical staining demonstrated numerous Treponema pallidum spirochetes within the lesion and epididymis, establishing the diagnosis of syphilitic orchitis. Serologic tests confirmed syphilis infection (TPHA positive; VDRL 1:128). Screening test for human immunodeficiency virus and other sexually transmitted infections was negative. Based on pathological findings and the concomitant skin rash, secondary syphilis with testicular involvement was diagnosed. The patient was treated with intramuscular benzathine penicillin G, achieving complete serologic response, with no recurrence after two years of follow-up.
Syphilitic orchitis is an uncommon but clinically relevant differential diagnosis of testicular masses. In the context of increasing syphilis incidence, particularly among high-risk populations, clinicians should consider serologic screening for Treponema pallidum in patients with atypical testicular lesions and negative tumor markers. Early recognition may support a conservative management approach, preventing unnecessary surgical procedures and ensuring prompt treatment.
Not applicable.

PMID:
42469661
Bibliographic data and abstract were imported from PubMed on 18 Jul 2026.

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