Primary Rectal Syphilis Mimicking Lymphoma: A Case Report and Literature Review.

Primary rectal syphilis is a rare disease that can be misdiagnosed as lymphoma or other rectal cancers on sigmoidoscopy or CT. Here, we report a case of primary rectal syphilis mimicking rectal malignancy in a 23-year-old male who presented with a rectal mass and multiple lymphadenopathies. In this case report and literature review, we focused on the CT findings and endoscopic observations of primary rectal syphilis. Infectious diseases, such as rectal syphilis, should be considered in the differential diagnosis of young patients with unusual rectal lesions and disproportionately extensive lymphadenopathies.