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tuberculosis persists as a common illness in developing countries , and western countries are experiencing a resurgence due to rising numbers of patients with acquired immunodeficiency syndrome1 , 2 ) .
intra - abdominal tuberculosis , including peritonitis , enterocolitis , and mesenteric lymphadenitis , is relatively rare among extra - intestinal tuberculosis , although it is of considerable clinical importance3 - 6 ) . in korea , although the exact incidence of intra - abdominal tuberculosis is unknown , tuberculous enterocolitis has been reported to account for 4.8% of all tuberculosis , and therefore , intra - abdominal tuberculosis is clinically relevant in korea .
intra - abdominal tuberculosis can present atypical clinicopathological features , which can make a proper diagnosis difficult8 - 10 ) .
we present here an unusual case of solitary intra - abdominal tuberculous lymphadenopathy mimicking duodenal gastrointestinal stromal tumor ( gist ) .
a 22-year - old woman presented with epigastric discomfort and intermittent dark - colored stools of two months duration .
she had no previous illness and denied constitutional symptoms such as fever , weight loss , or night sweating .
laboratory studies showed a hemoglobin of 13.9 g / dl , leukocytes of 7,580/mm , and an esr of 17 mm / hr . other biochemical tests results were within normal ranges , and anti - hiv ab was negative .
an esophagogastroduodenoscopic ( egd ) examination revealed a round mass of about 3-cm at the duodenal bulb , with normal surrounding mucosa and central ulceration ( figure 1 ) .
chest x - ray films showed inactive pulmonary tuberculosis at the left upper lobe , and abdominal computed tomography ( ct ) revealed a well - defined round mass that enhanced as gastric mucosa , at the posterior wall of the duodenal bulb suggestive of duodenal gist ( figure 2 ) .
endoscopic ultrasonography ( eus ) showed an ulcerative hypoechogenic mass at the submucosal layer of the duodenal bulb ( figure 3 ) .
exploratory laparotomy was performed to exclude the possibility of malignant gist of the duodenum . during laparotomy
, a solitary mass was detected around the hepatic artery , which penetrated the duodenal bulb .
the mass was excised and a histopathological analysis revealed lymphadenopathy with caseous granuloma ( figure 4 ) .
polymerase chain reaction of dna extracted from the node was positive for tuberculosis and acid - fast bacilli were found by ziehl - neelsen tissue staining .
the patient was diagnosed with solitary tuberculous lymphadenopathy and discharged on anti - tuberculosis medication .
abdominal mesenteric lymphadenopathy is a relatively common manifestation of intra - abdominal tuberculosis , which occurs as a regional component of primary or secondary disease
. involved mesenteric nodes may form independent masses or they may adhere to adjacent structures .
tuberculosis usually affects multiple lymph node groups simultaneously , though isolated retroperitoneal lymphadenopathy is uncommon11 , 12 ) .
most tuberculous lymphadenopathies are visualized by abdominal ct as enlarged nodes with hypodense centers and peripherally hyperdense enhancing rims11 ) as conglomerate mixed density nodal masses , or as enlarged masses with homogeneous density12 ) . in the present case ,
an exophytic oval mass was noted on an abdominal ct scan on the posterior wall of the duodenal bulb .
moreover , it presented as a submucosal mass with central ulceration and suspected bleeding foci on egd examination .
most cases of abdominal tuberculosis are complications of pulmonary tuberculosis , and thus in this patient with evidence of inactive pulmonary tuberculosis , a diagnosis of solitary mesenteric tuberculous lymphadenopathy with penetration into the duodenal wall appeared unlikely , and therefore , we suspected that the lesion was a duodenal gist .
gists are generally located in the stomach ; only 4% of cases are reported in the duodenum . however , despite their relative infrequency small bowel gists frequently manifest as gastrointestinal bleeding , abdominal pain , or as a palpable mass13 , 14 ) , and can display unpredictable malignant behavior notwithstanding their small size .
duodenal gists can thus have a poorer prognosis than gists of the stomach15 , 16 ) . because it is difficult to rule out duodenal gist and because of the likelihood of bleeding or malignancy
laparotomy revealed a solitary mesenteric lymphadenopathy penetrating the duodenal bulb , and histopathologic analysis revealed it to be a tuberculous lymphadenopathy .
eus - guided fine - needle aspiration ( fna ) has recently emerged as an important modality for diagnosing gist17 ) .
moreover , ultrasound - guided fna offers a safe method for obtaining proof of tuberculosis in patients with suspected intra - abdominal tuberculosis18 , 19 ) .
it is regrettable that we did not perform fna prior to laparotomy in the present case .
the preferred treatment of intra - abdominal tuberculosis is anti - tuberculous medication ; surgical management is normally reserved for complications or diagnostic uncertainty . in conclusion ,
intra - abdominal tuberculosis can present a variety of conditions and in areas with a high prevalence the possibility of tuberculosis must be considered .
tuberculosis is curable when a diagnosis is made sufficiently early and appropriate treatment is started .
tuberculosis remains prevalent in developing countries and has recently re - emerged in the western world . 
 intra - abdominal tuberculosis can mimic a variety of other abdominal disorders , and here we describe a patient with solitary tuberculous mesenteric lymphadenopathy mimicking duodenal gastrointestinal stromal tumor ( gist ) . 
 a 22-year - old woman complained of epigastric discomfort and was presumed to have a duodenal gist after an endoscopic examination and abdominal ct scan . 
 however , exploratory laparotomy revealed an enlarged node penetrating the duodenal bulb , which was diagnosed histopathologically as tuberculous lymphadenitis . 
 this case suggests that in regions with a high prevalence of tuberculosis , intra - abdominal tuberculosis is often mistaken as a malignant neoplasm . 
 a high index of suspicion and the accurate nonsurgical diagnosis of intra - abdominal tuberculosis continues to be a challenge .