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Paper text:
actinomycosis is an infrequent invasive chronic inflammatory disease caused mainly by actinomyces israelii , gram - positive , filamentous , anaerobic bacteria .
actinomycosis occurring primarily in urachal remnants is rare and may mislead the clinicians to diagnose urachal carcinoma .
we report one such case of urachal actinomycosis in a 50-year - old male with lower abdominal pain and mass palpable mimicking a urachal tumor .
a 50-year - old man , hailing from south india , came to the urology outpatient department with complaints of lower abdominal pain , dysuria , and dribbling of urine for 2 months duration .
clinically , he was afebrile and per - abdomen examination revealed a vague mass of 7 cm palpable at the suprapubic region .
computed tomography scan of the abdomen revealed an irregular mass seen superior to fundus of urinary bladder appearing adherent to mesentery and bowel loops and suggested an urachal remnant associated lesion with infiltration figure 1 .
excision of the mass with partial cystectomy and resection of involved ileal segments was done figure 2 .
the specimen was sent for histopathological examination . computed tomography of the abdomen showing an irregular mass seen superior to fundus of urinary bladder appearing adherent to mesentery and bowel loops
grossly , we received an irregular soft tissue mass measuring 12 cm  15 cm  4 cm with umbilicus on the one side and dome of the bladder on the other side .
we also received two loops of intestine with attached serosal mass measuring 4 cm  3 cm  2 cm .
after adequate sampling , sections from the urachal remnant revealed actinomycotic colonies surrounded by microabscesses and dense inflammatory fibrotic lesion figure 3 .
small intestinal segments showed a similar lesion in the serosa but not in the mucosa , confirming it to be a primary urachal actinomycosis .
photomicrograph showing high power view of h and e section of actinomycotic colonies surrounded by microabscesses the patient was started on intravenous penicillin and recovered without complications .
the most common risk factor includes use of intrauterine contraceptive devices in female , and others include history of bowel surgery such as perforated acute appendicitis , perforated colonic diverticulitis , penetrating trauma to the abdomen , and persistent urachal remnant .
our patient showed two of the risk factors of persistent urachal remnant and an earlier appendicectomy .
the infiltrative nature of the bacteria into the surrounding organs can be explained by production of proteolytic enzyme .
there are no specific radiological signs to distinguish actinomycotic lesions from malignancy due to its infiltrative nature .
definite diagnosis before surgery is difficult unless patient had discharging sinuses in the lower abdomen .
demonstration of the colonies of actinomycosis by histopathological examination is the definitive diagnosis , and hence , adequate sampling and extensive scanning must be done . in a study of 33 patients with pelvic actinomycosis by marella et al .
, 19 patients had intrauterine contraceptive devices and only four of them had urachal remnants .
exploratory laparotomy was done in most of them , and definite diagnosis was made by histopathological examination after excision of the mass .
it has a good prognosis and is curable with antibiotics such as penicillin and amoxicillin .
it is important to consider it in the differential diagnosis of patients presenting with lower abdominal pain and hard suprapubic mass with or without discharging sinuses . to the best of our knowledge ,
primary actinomycosis occurring in urachal remnants is rarely documented in literature and may mislead the clinicians to diagnose urachal carcinoma . 
 a 50-year - old man came with complaints of lower abdominal pain , dysuria , and dribbling of urine for 2 months . 
 a vague mass of 7 cm was palpable in the suprapubic region . 
 imaging of the abdomen revealed an irregular mass seen superior to fundus of the urinary bladder appearing adherent to mesentery and bowel loops , suggesting an urachal remnant associated lesion with infiltration . 
 provisional diagnosis of urachal carcinoma was considered . 
 excision of the mass with partial cystectomy and resection of involved ileal segments were done . 
 microscopic examination revealed actinomycotic colonies surrounded by microabscesses and dense inflammatory fibrotic lesion . 
 small intestinal segments showed a similar lesion in the serosa .