the prevalence of syphilis in the normal population has decreased significantly since 1977 in korea ( 1 , 2 ) . however , in western countries the incidence of syphilis has risen , mainly in the 20 - 24 age group and its clinical manifestations have been various ( 3 ) . sexual activity has become more acceptable in our culture recently , initiating various forms of sex , and as a result , many different clinical conditions of sexually transmitted disease ( std ) have appeared . it is usually asymptomatic and less frequently presents as proctitis , ulcer and pseudotumors ( 3 , 4 ) . therefore , it is difficult to diagnose and physicians occasionally might prescribe inappropriate treatments ( 5 , 6 ) . in this paper we describe a case of primary rectal syphilis which was suspected to be rectal cancer . he complained of bowel habit change with tenesmus , mucous discharge , anal pain and intermittent presence of blood in stool . he had a 2 cm sized , firm , non - tender and indurated nodule on the left side of the inguinal area and multiple condyloma acuminatum around the anus . sigmoidoscopy in our gastrointestinal endoscopy unit showed two indurated masses of 1.5 to 2 cm on the posterior wall of the middle and lower rectum ( fig . the masses had a coin like appearance , and each of them had a slightly depressed and ulcerated surface . the vdrl quantitative test was 1:64 and the fta - abs igm and igg test was positive . a human immunodeficiency virus ( hiv ) the patient was treated with intramuscular penicillin g benzathine ( 2,400,000 iu im/1 week , thrice ) . follow - up sigmoidoscopy after 1 month showed nearly complete regression of the chancre ( fig . a repeat biopsy was done and the histologic result showed focal lymphoid hyperplasia . a vdrl quantitative test after 3 months was 1:1 . most physicians have a tendency to consider rectal ulceration as a neoplasm ( 7 , 8) . similarly in our case symptoms and signs suggested rectal neoplasia and the clinical history did not reveal homosexuality . however , after the vdrl test the patient confessed that he had been raped by a homosexual male . therefore , when rectal syphilis is suspected ( i.e. , perianal condyloma acuminatum associated with inguinal lymphadenopathy ) the history of sexual intercourse , especially rectal intercourse , has to be taken . a dark - field examination is recommended by many studies ( 3 ) . in our case , however , a dark - field examination was not performed , because rectal chancre was highly suggested by the clinical history , anorectal lesions , pathologic findings and positive serologic test . additionally , like other syphilis cases benzathine penicillin therapy induced a rapid regression of the rectal lesions . we believe when a positive serologic syphilis test is associated with ulcerative lesion , additional laboratory tests are not necessary . inguinal lymphadenopathy need not require an initial biopsy when evidence of regional infection is present . usually after antibiotic therapy of at least 4 weeks , most physicians might decide whether a biopsy is necessary . in this case , however , the physician did not have experience recognizing rectal syphilis , so he immediately obtained a biopsy specimen from the inguinal lesion . . in western countries the incidence of rectal syphilis is rising , especially in groups of active homosexual males . bassi et al . emphasized in his case report that endoscopists should keep in mind the rising incidence of syphilis ( 3 ) . therefore an initial physician should encourage his / her patient to inform him / her of the patient 's sexual history .
a 30-yr - old man was referred for suspicious rectal cancer because of ulcerated lesions in the rectum and a palpable mass in left inguinal area . 
 sigmoidoscopy showed two indurated masses and histologic evaluation of biopsy revealed obliterative endarteritis with heavy plasma cell infiltration . both venereal disease research laboratories ( vdrl ) and 
 fluorescent treponemal antibody absorption ( fta - abs ) tests were positive . 
 after injection of penicillin g benzathine for 3 weeks , the rectal chancre and the palpable mass disappeared .