The Great Mimicker Gets Caught: A Rare Case of Syphilis in the Gastrointestinal Tract.

Syphilis is a sexually transmitted disease that impacts multiple organ systems and can mimic various diseases and is an extremely rare cause of proctitis in men who have sex with men and transgender females. We present a case of a 49-year-old transgender female with a medical history significant for diabetes mellitus and hyperlipidemia who presented to the emergency department with dull abdominal pain in the left upper and lower quadrants for two days. She had non-bloody, nonbilious emesis, 10-pound weight loss over 1 month, and constipation for 2 weeks. Laboratory results showed a cholestatic pattern. Computed tomography of the abdomen showed rectal wall thickening, multiple enlarged perirectal adenopathy, and mild inflammatory infiltration around the rectum suggesting superimposed proctitis. On colonoscopy, a possible rectal mass or severe proctitis with near complete obstruction was seen with initial pathology concerning for lymphoma or a rare type of colitis. The patient was empirically started on ceftriaxone and doxycycline leading to improvement in inflammation. Special stains requested were positive for Treponema pallidum confirming the diagnosis of syphilitic proctitis and highly suggestive syphilitic hepatitis. Few cases of syphilitic proctitis imitating rectal malignancy and syphilitic hepatitis have been reported. Syphilis requires exclusion as well as confirmation of spirochetes for high-risk populations with special staining. It is important to diagnose syphilis in special populations that are at high risk of contraction.