bevacizumab is a recombinant humanized monoclonal antibody that selectively blocks the activity of vascular endothelial growth factor ( vegf ) receptor .
the addition of bevacizumab to first or second line chemotherapy was associated with longer overall survival ( os ) and progression free survival ( pfs ) in metastatic colorectal patients .
the adverse events associated with bevacizumab include hypertension , proteinuria , thromboembolism , impaired wound healing , bleeding , perforation , reversible leukoencephalopathy syndrome , skin rash , and infusion - related hypersensitivity reactions .
we present here a case of fatal necrotizing fasciitis in a patient during bevacizumab treatment for colorectal cancer .
low anterior resection with ileostomy was performed for rectal mass 5 cm from anus . according to the tumor , node , metastases classification , the pathological stage of the carcinoma was t3n1m0 ( stage iiia ) .
the patient was treated with adjuvant 45 gy chemoradiotherapy with 5-fluorouracil 225 mg / m daily and then fluorouracil - leucovorin - oxaliplatin ( folfox4 ) regimen .
after two cycles of folfox4 regimen , serum carcinoembryonic antigen levels had increased . in the radiologic evaluation with chest and abdominal computed tomography , new liver metastases in both lobes
the hepatic metastases were unresectable , hence the patient shifted to regimen of 5-fluorouracil - leucovorin - irinotecan ( folfiri ) .
after 12 courses of the folfiri regimen every 2 weeks , the chemotherapy was stopped due to the stable liver metastases . because of the new metastatic lesions in the liver and pelvic recurrence , bevacizumab added to folfiri regimen . after 10 days of the third cycle of the folfiri - bevacizumab regimen , the patient was admitted with fever , weakness , abdominal pain and erythema of the proximal side of right thigh .
the laboratory evaluation revealed a white blood cell count of 22.000/l ( normal value 4,400 - 11,000/l ) with increased c - reactive protein to 160 mg / l ( normal value : 0 - 10 mg / l ) .
the magnetic resonance imaging ( mri ) of the pelvis showed widespread significant air - fluid level abscess in the tissues of right gluteus maximus , gluteus minimus and vastus muscles .
ultrasonography - guided drainage of the abscess was performed and 10f pigtail catheter was inserted to the abscess location .
the microbiological culture of the material was revealed vancomycin - resistant enterococcus ( vre ) , escherichia coli , and bacteroides fragilis .
patient responded to treatment for initial few days , but on the 7 day of the antibiotic treatment , acute renal failure and septic shock was developed .
necrotizing fasciitis is an uncommon severe soft tissue infection involving the subcutaneous fat and fascia . there are an estimated 3.5 cases of necrotizing fasciitis per 100,000 persons , with a case - fatality rate of 24% despite immediate treatment .
severe and acute onset of the pain at the infectious site is the most common clinical presentation .
the risk factors of necrotizing fasciitis are diabetes mellitus , malnutrion , trauma , operative interventions , and nonsteroidal anti - inflammatory drugs ( nsaids ) usage .
rarely , necrotizing fasciitis can develop due to all - trans - retinoic acid , bisphosphonates , and radiotherapy .
in addition , necrotizing fasciitis has also been reported in renal transplant recipient who treated with fk506 .
serious adverse events with bevacizumab treatment were hemorrhage , gastrointestinal perforation , and arterial thromboembolic events .
one of the pathophysiologic mechanism of necrotizing fasciitis is subcutaneous arteries thrombosis and tissue ischemia , bevacizumab can be the etiologic factor for this .
the naranjo probability score revealed that it was probable ( + 5 ) that bevacizumab might be responsible for necrotizing fasciitis .
we believe that in our patient , necrotizing fasciitis is due to bevacizumab treatment because there was no additional risk factor and there is temporal relationship between necrotizing fasciitis and bevacizumab treatment . in conclusion
, we presented fatal necrotizing fasciitis in a patient during bevacizumab treatment for rectal cancer .
although precise mechanism is not clear , necrotizing fasciitis is a fulminant disease and can be observed during bevacizumab treatment .
 bevacizumab is a recombinant humanized monoclonal antibody that selectively blocks the activity of vascular endothelial growth factor ( vegf ) receptor and it is used in metastatic colorectal patients . 
 we present here a case of fatal necrotizing fasciitis in a patient during bevacizumab treatment for colorectal cancer . in our review of the literature , 
 necrotizing fasciitis was not reported before or during bevacizumab treatment . 
Introduction
Case Report
Discussion