nonbacterial thrombotic endocarditis ( nbte ) is a disease characterized by the presence of small sterile vegetations on cardiac valve leafleats.1 ) the vegetations are composed of fibrin , platelet aggregates and red blood cells without evidence of inflammation or bacteria.2 ) nbte is a rare disease entity usually identified in patients with advanced stages of malignancy , infection or other systemic illnesses associated with hypercoagulable states.1 ) the diagnosis of nbte is difficult because there are no pathognomonic symptoms or signs , and it is usually associated with life - threatening underlying conditions.1)2 ) herein , we report a patient who was diagnosed with ntbe with an unusual clinical presentation : mesenteric venous thrombosis . a healthy 37-year - old man visited our emergency room with fever , abdominal pain and bloody diarrhea , which had all started five days ago . he was a current smoker and had a 34 pack - year of smoking history . the patient 's fever and diarrhea subsided through the use of acetaminophen and an anti - diarrheal agent , however , the abdominal pain persisted . at the initial examination , he was afebrile and his vital signs were unremarkable with a blood pressure of 147/94 mm hg , a pulse rate of 79 beats / min and a body temperature of 36.3. his abdomen was distended , and there was guarding with tenderness and rebound tenderness . inflammatory markers , including white blood cell count ( 19630/mm ) and c - reactive protein level ( 14.03 mg / dl ) , were markedly elevated . abdominal computed tomography ( ct ) scan revealed small bowel infarction associated with acute mesenteric vein thrombosis . no thrombi or emboli in the arterial system were identified on covered ct scan ( fig . 1 ) . the patient underwent an emergent surgery for bowel resection . in the operative field , the small bowel mesenteric veins were occluded with thrombi , and the mesentery was edematous . although the abdominal pain resolved after surgical resection of the ischemic bowel , the patient became febrile . his body temperature rose to 40. laboratory examinations including blood culture , anti - nuclear antibody , anti - phospholipid antibody , anti - neutrophil cytoplasmic antibody , factor v leiden mutation , homocysteine , factor xi , factor viii , protein c , protein s , and anti - thrombin iii were done , but they did not reveal any meaningful positive results . a disseminated intravascular coagulation ( dic ) profile also did not show significant analytical findings { prothrombin time was 13.1 seconds ( normal range : 10.7 - 11.9 ) , activated partial thromboplastin time was 30.8 seconds ( normal range : 19.6 - 36.0 ) , fibrinogen was 366 mg / dl ( normal range : 160 - 380 ) , fibrinogen degradation product was 16.7 ug / ml ( normal range : 0.0 - 4.9 ) , and d - dimer was 5.61 mg / l ( normal range : 0 - 0.55)}. electrocardiogram showed a normal sinus rhythm without st - t segment or t wave changes . surprisingly , three large hypermobile masses were found attached to the ventricular side of the anterior mitral valve leaflet and its chordae tendineae . tte revealed normal left ventricular size and normal systolic function with 72% of ejection fraction . malignancy evaluations with tumor markers and additional ct scans of the thorax were also unremarkable except for the masses in the left ventricle . on suspicion of infective endocarditis , serial blood cultures were performed again and empirical antibiotic therapy with ceftriaxone and gentamycin was started . however , the high fever persisted for the following 3 days . due to the patient 's poor response to antibiotics and high risk of systemic embolization , the cardiac masses were excised through an open - heart surgery . in the operative field , three masses were identified : one attached to the a2 portion of the ventricular side of the anterior mitral valve leaflet , another attached to the a2-a3 marginal chordae tendineae , and the last attached to the interventricular septum . the surgically resected masses were composed of necrotic fibrin thrombus and focal valvular tissues with fibromyxoid degeneration and minimal inflammatory reaction . no microorganism was identified in the patient 's serial blood culture studies as well . he was stable after the cardiac surgery and discharged with warfarin two weeks later . the patient has been on regular follow - up with no clinical evidence of disease for one year since the discharge . patients with nbte tend to manifest with arterial thrombosis resulting in embolism and infarction in the peripheral organs . in addition , the brain was found to be commonly affected as well in previous studies where about half of the patients diagnosed with nbte showed neurologic events caused by cerebral infarction.3)4 ) however , in this case , the small bowel was the only organ affected by thrombosis , and the small bowel infarction was caused not by arterial but by venous thrombosis . although a previous autopsy study showed that about 7% of nbte patients had mesenteric venous thrombosis,3 ) there has been no report of any ante mortem case of the condition . while the pathogenesis of nbte is not completely understood , previous studies have revealed that both endothelial damage and hypercoagulable states are important.1 ) cardiac stress , trauma or circulating immune complexes can cause valvular damage . when deformed or sometimes normal valves are exposed to hypercoagulable states , such as malignant neoplasm , autoimmune diseases or dic , thrombotic vegetations are formed.1)2)4 ) therefore , patients diagnosed with nbte are often associated with such conditions.1)2)3 ) in particular , malignancy is the most common underlying condition ; 78% of nbte patients were diagnosed with malignancy at autopsy,3 ) and there have been a few ante mortem case reports of nbte associated with malignancy.5)6 ) though a cause for the hypercoagulable milieu should have been identified in our nbte patient , no evidence of an underlying condition was found despite our efforts . in reaching the diagnostic conclusion of nbte , we excluded infective endocarditis . first and foremost , it was not likely to be an infective endocarditis since there was no evidence of infection by a microorganism at all ; all the blood culture results were negative . the patient did not respond to antibiotic therapies , and the pathologic specimen of the thrombi showed no evidence of infestation by microorganisms . secondly , our patient 's valves were structurally intact and functionally normal , while the valves in infective endocarditis are often destructed with or without abscess.7 ) as part of the next step , left ventricular thrombus was excluded . in terms of location , left ventricular thrombus is usually seen in regions of blood stasis or low - velocity blood flow like ventricular aneurysms , which are not usually valves.8 ) therefore , left ventricular thrombi are formed in an akinetic or a dyskinetic apex or in diffuse left ventricular dysfunction.8 ) the few reported cases of mural thrombi of the left ventricle with normal systolic function and without regional wall motion abnormality have been associated with hypercoagulable states , such as myeloproliferative disorder or eosinophilic endocarditis predisposing thrombus formation.9)10 ) in our case , one of the masses was attached to the left ventricular septum . our patient experienced no ischemic cardiac insult of any kind , and the heart function was too normal for an area of blood stasis to occur . in our case , the sizes of the cardiac masses were 1616 , 1210 , and 610 mm , respectively , which were not quite typical of nbte . previous studies have reported that , the vegetations of nbte were usually less than 10 mm1)2)3 ) and affected the atrial surfaces of the mitral valves and the ventricular surfaces of the aortic valves.1 ) however , none of these characteristics are independently diagnostic.8 ) for example , an autopsy study demonstrated vegetations of nbte whose diameters ranged between 2 and 25 mm.11 ) in addition , some case reports showed vegetations of nbte larger than 10 mm12)13 ) and a vegetation attached to a chordal structure.5 ) therefore , our case can not be ruled out of the boundaries of nbte simply because of unusual sizes and locations of the vegetations . since most of the underlying diseases of nbte are malignancies , unfractionated heparin is recommended for anticoagulation.1)4 ) however , there is no guideline regarding the duration and methods of anticoagulation therapy for nbte patients without cancer.4 ) our patient chose warfarin over heparin for the sake of convenience . given that our patient has been on follow - up without evidence of new thrombosis , a vitamin k antagonist might also be as effective as low molecular weight heparin . based upon our results , cardiac surgery should be considered in selected patients who have curable underlying diseases , severe valvular dysfunction or recurrent embolic events despite anticoagulation therapy.14 ) we described the first case of nbte without evidence of arterial thrombosis or underlying systemic illnesses . until recently , ante mortem cases of nbte have been scarcely reported . however , with the gradual progress and improvement of imaging techniques , more ante mortem cases of nbte are expected to be identified . cardiac masses that are not quite fit for being diagnosed as infected vegetations , left ventricular thrombi or tumors should be suspected of vegetations of nbte . prompt diagnosis and treatment of nbte could improve the overall outcome of the treatment and prognosis of the disease by reducing complications .
ante mortem cases of venous thrombosis in patients with nonbacterial thrombotic endocarditis ( nbte ) have not yet been reported . 
 we describe a rare case of nbte in a patient with mesenteric vein thrombosis . a healthy 37-year - old man with abdominal pain and fever underwent emergency small bowel resection due to bowel ischemia resulting from mesenteric vein thrombosis . 
 transthoracic echocardiography revealed multiple mobile masses attached to the anterior leaflet of the mitral valves and their chordae tendineae . on suspicion of infective endocarditis 
 , the cardiac masses were excised through open - heart surgery . 
 however , pathologic reviews were compatible with nbte . 
 the patient was stable after the cardiac surgery and was treated with warfarin . 
 laboratory and imaging findings regarding his hypercoagulable condition were all negative .