small bowel cancers are very rare , accounting for only 3%-6% of all gastrointestinal neoplasms.12 because small bowel cancers lack specific clinical manifestations , and the entire small intestine is not easy to access , it is very difficult to diagnose cancers in this region . the development of balloon - assisted enteroscopy ( bae ) and capsule endoscopy has initiated a new era in small bowel lesion diagnosis . bae is a relatively noninvasive method compared to surgical resection , with a diagnostic yield of approximately 43%-80% for small bowel diseases.3 bae has advantages over other diagnostic modalities such as capsule endoscopy , not only in terms of access to the entire small bowel with real - time observation , but also in facilitating endoscopic intervention , tissue confirmation with biopsy , and procedures such as stenting and balloon dilatation.456 here , we report a case of small bowel metastatic carcinoma observed with double balloon enteroscopy ( dbe ) in a patient with a history of multiple cancers . a 69-year - old woman was referred to our clinic complaining of cramping abdominal pain that had persisted for 10 days and had been aggravated for one day before admission due to a small bowel obstruction . she had a history of multiple cancers including ovarian cancer ( treated by total abdominal hysterectomy and bilateral salpingo - oophorectomy 12 years prior ) , bladder cancer ( treated by transurethral resection of the bladder tumor 5 years prior ) , and breast cancer ( treated by left modified radical mastectomy followed by adjuvant chemotherapy 6 years prior ) . on admission , her blood pressure was 110/70 mmhg , heart rate was 92 beats / min , body temperature was 36.4 , and respiratory rate was 20 breaths / min . laboratory data revealed anemia ( white blood cells , 8,100/mm ; hemoglobin , 8.0 g / dl ; platelets 297,000/mm ) , and biochemical tests revealed no abnormal findings ( crp , 4.18 mg / l ; glucose 162 mg / dl ; bun , 11.6 mg / dl ; creatinine , 0.73 mg / dl ; ast , 20 iu / l ; alt , 13 iu / l ; total bilirubin , 0.48 mg / dl ; protein , 7.2 g / dl ; albumin , 4.0 g / dl ; pt , 13.3 seconds [ international normalized ratio 1.0 ] , and aptt , 29.7 seconds ) . conventional abdominal ct scans revealed a circumferential wall - thickening lesion in the proximal to mid jejunum , and because the patient had a history of multiple cancers , this lesion was treated as suspicious and assumed to represent metastatic small bowel cancer or ( less likely ) adenocarcinoma ( fig . a fluoroscopic small bowel follow - through revealed a 2-cm circumferential wall - thickening lesion appearing as an " apple core sign " in the mid jejunum ( fig . 1c ) . for pathological confirmation , antegrade dbe ( en450t5 , fujinon , saitama , japan ) an approximately 2-cm long encircling ulcero - infiltrative lesion was noted at the mid jejunum ( depth of insertion approximately 100 cm ) with partial luminal obstruction ( fig . two pieces of tissue were biopsied , and histological examination revealed atypical epithelial nests with nuclear pleomorphism and frequent mitosis ( fig . the patient underwent small bowel resection for her continuing abdominal pain , and the final pathological diagnosis was small bowel metastatic carcinoma originating from the breast ( fig . 4 ) . the patient underwent chemotherapy in the oncology department , and we administered docetaxel monotherapy , the most common drug for the treatment of breast cancer ( 75 mg / m on day 1 , 21 days for 1 cycle ) . following 6 cycles of chemotherapy , new metastatic lesions in the brain were observed , and brain radiotherapy was performed 1 year after diagnosis . no remnant lesions or new lesions have been found , and the patients visited the hospital every 3 months for follow - up investigations under good conditions . since the introduction of dbe , small bowel tumors can be easily diagnosed without surgical resection , and several studies have reported the characteristics of diagnosing small bowel tumors using dbe . recent studies concerning small bowel tumors using dbe have shown that the most common type of small bowel carcinoma is metastatic small bowel cancer followed by adenocarcinoma , carcinoid tumors , and lymphoma.13 metastatic small bowel cancer is more frequent than primary small bowel cancer . however , the overall incidence of metastatic small bowel cancer is very low . the most common symptoms are abdominal pain , nausea , vomiting , and overt gastrointestinal tract bleeding . the most frequent endoscopic findings of small bowel cancer are stenosis or ulceration , followed by submucosal tumors and multiple white nodules.4 in addition , the most frequent location for small bowel tumors is the jejunum , followed by the ileum and duodenum.2 although there are some differences between the studies reported to date , the most common metastatic cancers involving the small bowel are primary tumors such as malignant melanoma , colon cancer , cervical cancer , and ovarian cancer.7 metastasis to the small bowel is usually hematogenous or due to direct invasion from intraperitoneal seeding . primary cancers of the colon , ovary , uterus , and stomach are usually spread to the small bowel by direct invasion or intraperitoneal spread , whereas primary cancers from the breast , lung , and melanoma metastasize to the small bowel by a hematogenous route.8 the overall incidence of metastatic small bowel cancer is very low , and as mentioned earlier , most metastatic cancers have neither specific symptoms nor signs until they cause small bowel obstruction . therefore , it is very difficult to detect metastatic small bowel cancer . due to the delays in diagnosis , patients with metastatic small bowel cancer are diagnosed at relatively advanced stages and usually have a poor prognosis.4 the present case involved small bowel obstructions of unknown origin in a patient with a history of multiple cancers . patients with small bowel obstruction usually require surgical resection to relieve the obstructive symptoms and diagnose the etiology . however , the preoperative assessment of small bowel obstructions by dbe enables surgeons to perform a scheduled operation by confirming the preoperative pathologic findings of the cancer 's etiology , and to prevent extensive small bowel resection by determining the extent or location of obstructive lesions . moreover , in recent years , the role of bae has expanded . besides diagnostic evaluation , deep small bowel enteroscopy enables the widening of bowel - obstructive lesions by endoscopic guided metal stent insertion.9 recurrence or metastasis of breast cancer is common , and occurs in 20%-30% of patients . the common sites for breast cancer metastasis are bone , lung , liver , and brain.710 metastasis to the gastrointestinal tract is uncommon and when it does occur , it mainly involves the stomach , colon , or rectum.1112 metastasis to the small bowel is very rare , comprising approximately 0.08% of metastatic breast cancers.13 there are very few reports of the small intestinal metastasis of breast cancer . in the present case , metastatic small bowel cancer was diagnosed 6 years after the initial diagnosis of breast cancer . the median interval for recurrence after surgical resection for breast cancer is 2 to 3 years , and recurrence is within 5 years in 90% of cases , although a 30-year interval between the initial diagnosis of breast cancer and the presentation of metastasis has been reported in the literature.711 therefore , metastatic small bowel cancer should be considered in patients with gastrointestinal symptoms or a newly identified gastrointestinal neoplasm , especially those with a history of colon cancer , ovarian cancer , lung cancer , or breast cancer , even if the patients were diagnosed with cancer a long time ago.14 in this paper , we reported small bowel obstruction due to small bowel metastasis from breast cancer diagnosed by dbe in a patient with a history of multiple cancers . to our knowledge , this is the first detailed report of the preoperative diagnosis of small intestinal metastatic breast cancer by dbe . there is no doubt that dbe is one of the most useful devices for approaching a suspected small bowel tumor , and for making a histological diagnosis before surgery .
small bowel tumors are very rare and generally malignant . as a result of the anatomical location and nonspecific manifestations of small bowel tumors , they are very difficult to diagnose . 
 balloon - assisted enteroscopy is a relatively noninvasive method compared to surgical resection , and allows for real - time observation , tissue confirmation with biopsy , and interventional procedures . here 
 , we report the case of a 69-year - old woman with a small bowel metastatic carcinoma observed with double balloon enteroscopy ( dbe ) . she had a history of multiple cancers including ovarian cancer , bladder cancer , and breast cancer . 
 the antegrade dbe procedure was performed before surgery for biopsy tissue confirmation . 
 the patient underwent small bowel resection , and the final diagnosis was the same as that determined by preoperative biopsy . 
 the final diagnosis was metastatic small bowel cancer originating from a cancer of the breast . 
 this is the first detailed report of the preoperative diagnosis of small intestinal metastatic breast cancer by dbe .