celiac disease ( cd ) is a chronic systemic autoimmune disorder affecting genetically predisposed individuals , triggered and maintained by the ingestion of gluten . gluten is a protein found in wheat , rye , barley ( malt ) and oats . originally described by gee 1 , it can induce a strong immune response in sensitive patients which is both cellular ( t cells ) and humoral ( b cells ) . the disease is characterized by a variable combination of the haplotypes hla dq2 and/or hla dq8 , enteropathy and the production of autoantibodies , including tissue anti - transglutaminase antibodies ( anti - ttg ) , anti - endomysial antibodies ( ema ) and deamidated gliadin peptide antibodies ( dpg ) 2 . dicke 3 demonstrated an association between cd and certain types of cereals and was the first to propose a gluten - free diet ( gfd ) . in recent years , advances in endoscopic technology techniques such as chromoendoscopy , fujinon intelligent chromoendoscopy , narrow band imaging , optical coherence tomography , water immersion , confocal laser endomicroscopy , high - resolution magnification endoscopy , capsule endoscopy and i - scan technology have been described . these tools may be used in combination with histology , increasing the diagnostic power of endoscopy in patients with cd 4 . advances in diagnostic and screening methods have contributed to an apparent increase in the incidence of cd . most patients ( >  80  % ) diagnosed with cd upon screening are asymptomatic or oligosymptomatic . in addition to gastrointestinal changes , cd patients may present neurological problems , dermatitis herpetiformis , anemia , early osteoporosis , hypoproteinemia , hypokalemia , and raised liver enzyme concentrations 5 . persistent cd - related inflammation of the duodenal mucosa causes atrophy and deformation of the villous architecture detectable on esophagogastroduodenoscopy ( egd ) . classic endoscopic markers include loss of kerckrings folds , scalloped folds , grooves , mosaic patterns , visible submucosal vessels and micronodules 6 
 7 . these markers are readily identified on conventional egd combined with chromoendoscopy , using methyl blue or indigo carmine instilled on the duodenal mucosa . with this technique , markers are identified with 91  % accuracy , compared to 9  % without chromoendoscopy ( p  <  0.001 ) 8 . if available , devices with zoom features ( e.  g. olympus gif - q160z , capable of 115 x magnification ) should be used 9 
 10 . at this level of magnification , villous atrophy can be identified in detail with 90.7  % sensitivity and 63  % specificity 11 and the extension of the affected tissue can be quantified . cd may be diagnosed based on clinical suspicion or during routine evaluations of patients with dyspepsia , gastroesophageal reflux disease and peptic disease . the method may also be used in follow - up of cd patients receiving gfd 12 . lifelong gfd use is currently the only safe and effective therapy , although alternative therapies can help reduce the need for dieting . studies have shown that 2  % to 5  % of patients with cd develop refractory disease , a severe complication associated with intestinal lymphoma and very poor prognosis 13 . in this study , we investigated the association between endoscopic features of the duodenal mucosa and histopathological findings ( interpreted according to the marsh classification ) in a cohort of patients with cd and propose an endoscopic classification of severity for this patient population . although the relevance of duodenal mucosal changes on conventional egd to the diagnosis of cd has been demonstrated in the literature , few endoscopists seem to be aware of the advantage of adopting chromoendoscopy and zoom as a routine diagnostic procedure . in view of the scarcity of literature on the subject , we believe that a detailed endoscopic classification of such changes will help understand the development of cd and standardize findings with regard to both severity and extension . in addition , a comparison between endoscopic and histopathologic findings will allow therapists to evaluate the repercussion of gluten on the intestinal mucosa with greater accuracy and establish a more reliable diagnosis of cd . although the relevance of duodenal mucosal changes on conventional egd to the diagnosis of cd has been demonstrated in the literature , few endoscopists seem to be aware of the advantage of adopting chromoendoscopy and zoom as a routine diagnostic procedure . in view of the scarcity of literature on the subject , we believe that a detailed endoscopic classification of such changes will help understand the development of cd and standardize findings with regard to both severity and extension . in addition , a comparison between endoscopic and histopathologic findings will allow therapists to evaluate the repercussion of gluten on the intestinal mucosa with greater accuracy and establish a more reliable diagnosis of cd . the design followed puc / pr guidelines ( pontifcia universidade catlica do paran , brazil ) and was approved by the unioeste / pr human research ethics committee and filed under entry # 344  /2011 . due to the retrospective nature of the study , three modalities of egd were employed : conventional egd , conventional egd combined with chromoendoscopy ( indigo carmine ) , and conventional egd combined with chromoendoscopy and zoom . histopathologic data from the time of diagnosis of cd were reviewed at citopar ( center of cytology and pathology , paran , brazil ) . patients of both genders aged >  14 years diagnosed with cd according to the criteria of the world gastroenterology organization 14 were eligible . the diagnosis of cd was based on serum positivity for ema iga 15 and/or anti - ttg 16 and on histopathological findings for the intestinal mucosa 17 . the medical records ( clinical data and egd images ) were retrieved from the electronic database ( sisclnica 2000 ) of a referral center in southern brazil ( gastroclnica cascavel ) covering the period from january 2000 to march 2010 . the initial sample was drawn from a universe of 34,540 egds of male and female patients older than 14 years of age ( with no repetition of egds ) and consisted of 109 patients presenting classic endoscopic markers 6 
 7 on conventional egd with chromoendoscopy ( indigo carmine ) , zoom at 115x ( olympus gifq-160z ) and biopsy of intestinal mucosa for histopathological analysis . the inclusion criteria were met by 85 of these 109 patients , of whom 64 ( 75.30  % ) were women ( mean age : 35 years ) and 21 ( 24.70  % ) were men ( average age : 34 years ) . the egd images of the final sample of 85 patients , representing the moment of diagnosis , were selected . the algorithm shown in fig .  1 was applied to each case . the biopsy specimens of the 85 patients were sent to citopar in the form of slides or paraffin blocks . the original block was used to prepare new slides in order to review each case at the moment of diagnosis and during follow - up on gfd . all specimens were reviewed by the same pathologist and interpreted according to the marsh classification system 17 . spearmans correlation coefficient was calculated and evaluated for statistical significance at the level of 5  % ( p  <  0.05 ) . sensitivity , specificity and positive likelihood ratios were estimated to evaluate egd accuracy , considering the histologic pattern ( marsh ) as the gold standard for the evaluation of cd . spearmans correlation coefficient was calculated and evaluated for statistical significance at the level of 5  % ( p  <  0.05 ) . sensitivity , specificity and positive likelihood ratios were estimated to evaluate egd accuracy , considering the histologic pattern ( marsh ) as the gold standard for the evaluation of cd . careful examination of the endoscopic images in the database supported establishment of a macroscopic correspondence between the severity of atrophy on egd and marsh grade ( 1992 ) (  supplementary fig .  1 ) . thus : 
 endoscopic association with histopathology the marsh ( 1992 ) egd type 0 ( regular , continuous , digitiform and occasionally foliaceous villi ) corresponds to marsh grade 0 ( pre - infiltrative ) . egd type i ( mostly regular villi , with some foci , but no mosaic pattern ) corresponds to marsh grade 1 ( infiltrative ) . egd type ii ( agglutinated but visible villi , mosaic patterns ) corresponds to marsh grade 2 ( hyperplastic infiltrative ) . egd type iii ( absence of villi , mosaic patterns ) corresponds to marsh grade 3 ( flat , destructive ) and 4 ( hyperplastic atrophic ) ( the appearance of the duodenal surface on egd was the same for the two histologic grades ) . regular , continuous , digitiform and occasionally foliaceous villi , corresponding to marsh grade 0 . b conventional egd  +  chromoendoscopy ( 0.5  % indigo carmine ) : continuous and regular mucosa . c conventional egd  +  chromoendoscopy  +  zoom ( 115x ) during follow - up of patient on gluten - free diet : normal , regular villi with no atrophic foci . regular , continuous , digitiform and occasionally foliaceous villi , corresponding to marsh grade 0 . b ) convencional egd  +  chromoendoscopy ( 0.5  % indigo carmine ) : continuous and regular mucosa . c ) conventional egd  +  chromoendoscopy  +  zoom ( 115   ) during follow - up of patient on gluten - free diet : normal , regular villi with no atrophic foci . egd type i. mostly regular villi , with some foci , but no mosaic pattern , corresponding to marsh grade 1 . a conventional egd : continuous and regular mucosa with minor atrophic foci but no mosaic patterns . b conventional egd  +  chromoendoscopy ( 0.5  % indigo carmine ) : minor atrophic foci , no mosaic patterns . c conventional egd  +  chromoendoscopy  +  zoom ( 115x ) : minor atrophic foci , no mosaic patterns . d slide stained with he ( 40x ) : duodenal mucosa with some shortened villi minor atrophic foci ( epithelial lymphocytosis ) . mostly regular villi , with some foci , but no mosaic pattern , corresponding to marsh grade 1 . a ) conventional egd : continuous and regular mucosa with minor atrophic foci but no mosaic patterns . b ) conventional egd  +  chromoendoscopy ( 0.5  % indigo carmine ) : minor atrophic foci , no mosaic patterns . c ) conventional egd  +  chromoendoscopy + zoom ( 115   ) : minor atrophic foci , no mosaic patterns . a conventional egd : continuous and regular mucosa with minor atrophic foci but no mosaic patterns . b conventional egd  +  chromoendoscopy ( 0.5  % indigo carmine ) : atrophic foci and mosaic patterns . c conventional egd  +  chromoendoscopy  +  zoom ( 115x ) : atrophic foci and mosaic patterns . d slide stained with he ( 40x ) : duodenal mucosa with poorly distinguishable villi , crypt hyperplasia and lymphocytosis . example below . 
 agglutinated but visible villi and mosaic patterns , corresponding to marsh grade 2 . a ) conventional egd : continuous and regular mucosa with minor atrophic foci but no mosaic patterns . b ) conventional egd  +  chromoendoscopy ( 0.5  % indigo carmine ) : atrophic foci and mosaic patterns . c ) conventional egd  +  chromoendoscopy  +  zoom ( 115   ) : atrophic foci and mosaic patterns . b conventional egd  +  chromoendoscopy ( 0.5  % indigo carmine ) : fissures , nodules , mosaic patterns , absence of villi . c conventional egd  +  chromoendoscopy  +  zoom ( 115x ) : flat , mosaic pattern , absence of villi . d slide stained with he ( 40x ) : severely atrophied duodenal mucosa without visible villi . a ) conventional egd : severe loss of kerkring s folds , nodules and fissures . b ) conventional egd  +  chromoendoscopy ( 0.5  % indigo carmine ) : fissures , nodules , mosaic patterns , absence of villi . c ) conventional egd  +  chromoendoscopy  +  zoom ( 115   ) : flat , mosaic pattern , absence of villi .   based on these correspondences , we developed an algorithm associating egd type and marsh grade in patients with cd (  fig.1 ) . our 85 patients with cd were diagnosed as follows : egd type i  =  5 patients ( 5.8  % ) of whom 4 ( 80  % ) were marsh grade 2 , and 1 ( 20  % ) was marsh grade 3 . egd type ii  =  25 patients ( 29.4  % ) of whom 4 ( 16  % ) were marsh grade 2 , and 21 ( 84  % ) were marsh grade 3 . egd type iii  =  55 patients ( 64.7  % ) of whom 4 ( 7.2  % ) were marsh grade 2 , 50 ( 90.9  % ) were marsh grade 3 , and 1 ( 1.8  % ) was marsh grade 4 . the results of the two diagnostic methods ( egd and histopathology ) were expressed as frequencies and percentages . as shown in table  1 , the estimated spearman correlation coefficient was r  =  0.33 ( p  =  0.002 ) , indicating a significant and positive association between the methods . however , despite the significant p value , the coefficient was not high . egd sensitivity was 69.9  % in relation to marsh classification , with a specificity of 66.7  % and a positive likelihood ratio of 2.1 . the spearman correlation coefficient ( r  =  0.33 ) shows a significant association between the methods ( p  =  0.002 ) . the incidence of cd in the united states has increased at least four - fold over the past decades . studies on the general population estimate an incidence of 0.8  % to 1.0  % 15 . on the other hand , many individuals with cd remain undiagnosed : the figure was 97  % in a study by 18 and , more recently , 95  % ( olmsted county ) , 90  % ( wyoming ) and 89  % ( maryland ) in a study based on a national health and nutrition survey 19 .   the large number of undiagnosed cases of cd may be explained by variations in clinical presentation , which is not restricted to patients with gastrointestinal symptoms . thus , cd may affect patients with several atypical extraintestinal or oligosymptomatic disorders accompanied by abdominal pain , anemia , weight loss , neurological changes , hypoproteinemia , hypokalemia and high liver enzyme concentrations 20 . the delay in diagnosing cd is sometimes the result of the physicians lack of familiarity with clinical manifestations 21 . relatively little attention is given to this disorder in the united states , despite an incidence comparable to that of europe 22 . however , failure to clinically detect cd exposes cd patients to the risk of developing severe gluten - related disorders , including autoimmune diseases ( thyroiditis , hepatitis , herpetiform dermatitis and alopecia ) 23 , osteoporosis , anemia , neurologic changes and intestinal lymphoma 24 . the prevalence of undiagnosed cases may be reduced by careful endoscopic examination of the duodenum combined with chromoendoscopy , as proposed in this study , since most patients with dyspeptic symptoms are routinely submitted to egd . according to the national health council ( conselho nacional de sade , 2012 ) , the global incidence of cd is estimated at 1  % , but no official estimates are available for brazil yet . a study published in 2005 by the federal university of so paulo ( unifesp ) found an incidence of 1/214 for a sample of adult blood donors in so paulo 25 
 26 . in addition to atypical clinical manifestations , groups at risk for cd such as families with a history of down syndrome 27 
 28 , turners syndrome 29 and type i diabetes 30 
 31 , should be given more attention . the combination of egd and chromoendoscopy / zoom was first used to evaluate villous atrophy of the duodenal mucosa when badreldin et al . 11 assigned z - scores corresponding to 4 patterns of villous architecture ( from normal to absent villi ) to 58 patients . 32 submitted 27 untreated cd patients to egd with zoom , using an olympus gif - q160z device ( as in the present study ) . the authors instilled acetic acid on the intestinal villi and classified their findings into three patterns : normal areas , areas with partial atrophy , and areas with complete atrophy ( 100  % sensitivity compared to conventional egd ) , thereby potentially reducing the need for blind biopsies . in a study comparing egd +  chromoendoscopy / zoom images of 36 patients to histopathologic findings , 33 classified the observed villous patterns as normal , partially atrophied or completely atrophied , and found the spearman correlation coefficient ( 0.92 ) to be statistically significant ( p  <  0.001 ) . the studies described above inspired us to develop the endoscopic classification described in the current study . following a careful review , the classification was centered on the mosaic pattern characterizing moderately advanced forms of duodenal atrophy . interestingly , when the villous architecture is under recovery , the flat mosaic pattern reverts to a mosaic pattern with visible villi . eventually the mosaic pattern disappears , leaving only minor foci , followed by complete recovery (  fig .  2 ,  fig .  3 , fig .  4 and  fig .  5 ) . thus , the stages of atrophy observed when cd develops are observed in reversed order as the condition resolves . based on these observations , egd type 0 ( normal ) , type i ( minor atrophic foci ) and type ii ( mosaic pattern , visible villi ) were found to be equivalent to marsh grades 0 , 1 and 2 , respectively , while egd type iii ( mosaic pattern , villi not visible ) was found to be equivalent to marsh grades 3 ( destructive ) and 4 ( hyperplastic atrophic ) ( the appearance of the duodenal surface on egd is the same for marsh grades 3 and 4 ) . in view of these correspondences , an algorithm was developed associating endoscopic features and histopathological ( marsh ) findings ( fig if markers for cd are suspected , the patient is submitted to image - enhancing chromoendoscopy for confirmation , even without zoom . if necessary ( and available ) , the duodenum may subsequently be evaluated under magnification in order to determine the stage of atrophy . the use of the algorithm not only provides important data for the pathologist , but potentially increases the confidence of the physician interpreting the egd results due to the additional information on extension and macroscopic patterns . in the current study , a significant and positive association was observed between the 2 diagnostic methods ( egd vs. histopathology ) based on a cohort of 85 patients ( spearman correlation coefficient 0.33 ; p  =  0.002 ) ( table  1 ) with a sensitivity of 69.9  % , specificity of 66.7  % , and a positive likelihood ratio of 2.1 . egd combined with chromoendoscopy allowed to evaluate the entire surface of the duodenal mucosa macroscopically and detect changes , from minor foci to complete atrophy . when changes in the villous architecture were continuous ( as in severe cases ) , the association between the methods was stronger . conversely , in less severe cases ( minor foci ) , the association was weaker . this is most likely because egd evaluates a larger extension of the duodenal mucosa , providing a macroscopic view . as shown in this study , advances in endoscopic technology have made it possible to identify patterns of villous architecture during egd , making diagnosis more accurate . it is therefore reasonable to presume that egd will come to play an essential role in the diagnosis of cd , rather than simply provide a means of collecting biopsy specimens for histopathology 34 . the proposed endoscopic classification of patterns observed on egd ( combined with chromoendoscopy and zoom ) makes it possible to standardize atrophic changes in the duodenal mucosa of patients with cd . it should be stressed that conventional egd with chromoendoscopy ( without zoom ) is often sufficient to establish the level of atrophy . the agreement between the methods increases if the pathologist is informed of the extension of the affected mucosa ( using the proposed algorithm ) and of the egd type of each biopsy specimen . in this study the endoscopic images and histology where reviewed by only 1 endoscopist and 1 pathologist . a prospective design using this method would probably have yielded higher levels of agreement between endoscopy and pathology . the classification proposed in this study may be used to increase the agreement between egd and histopathology and the accuracy of diagnosis and follow - up . in addition , it provides endoscopists with an algorithm which will allow them to make more detailed evaluations ( using chromoendoscopy in cases of suspicion ) and , over time , reduce the prevalence of undiagnosed cd . our results suggest that : 1 ) changes in the duodenal mucosa detected on egd were significantly and positively associated with histopathologic findings ; 2 ) the more severe the atrophy , the stronger the association between the methods ; 3i ) when conventional egd images arouse suspicion of cd , chromoendoscopy should be employed for confirmation ; and 4 ) the proposed endoscopic classification is practical and easily reproducible and provides valuable information regarding disease extension . macroscopic evaluation of the extension of cd - related atrophy obtained with the use of the proposed algorithm is a helpful aid in histopathology . it also alerts endoscopists to the need of chromoscopy following routine egds with suspicion of cd . most cases in the present study were diagnosed with routine egd , with no specific clinical presentation , ( some patients had several previous egds , or even surgery for gastroesophageal reflux disease ) . macroscopic evaluation of the extension of cd - related atrophy obtained with the use of the proposed algorithm is a helpful aid in histopathology . it also alerts endoscopists to the need of chromoscopy following routine egds with suspicion of cd . most cases in the present study were diagnosed with routine egd , with no specific clinical presentation , ( some patients had several previous egds , or even surgery for gastroesophageal reflux disease ) .
background and study aims : celiac disease ( cd ) is a chronic systemic autoimmune disorder affecting genetically predisposed individuals , triggered and maintained by the ingestion of gluten . triggered and maintained by the ingestion of gluten , 
 celiac disease is a chronic systemic autoimmune disorder affecting genetically predisposed individuals . 
 persistent related inflammation of the duodenal mucosa causes atrophy architecture detectable on esophagogastroduodenoscopy ( egd ) and histopathology . 
 we investigated the association between endoscopic features and histopathological findings ( marsh ) for duodenal mucosa in celiac disease patients and propose an endoscopic classification of severity . 
 patients and methods : between january 2000 and march 2010 , an electronic database containing 34,540 edgs of patients aged >  14 years was searched for cases of cd . 
 out of 109 cases , 85 met the inclusion criteria : conventional egd combined with chromoendoscopy , zoom and biopsy . 
 egd types 0 , i and ii corresponds to marsh grades 0 , 1 and 2 , respectively , while egd type iii corresponds to marsh grade 3 and 4 . 
 results : five patients ( 5.8  % ) were egd i but not marsh grade 1 ; 25 patients ( 29.4  % ) were egd ii , 4 of whom ( 16  % ) were classified as marsh grade  2 ; and 55 patients ( 64.7  % ) were egd iii , 51 ( 92.7  % ) of whom were classified as marsh grades 3 and 4 . the spearman correlation coefficient ( r  =  0.33 ) revealed a significant association between the methods ( p  =  0.002 ) . 
 conclusions : changes in the duodenal mucosa detected on egd were significantly and positively associated with histopathologic findings . 
 the use of chromoendoscopy in addition to conventional egd enhances changes in the duodenal mucosa and permits diagnosis of cd , even in routine examinations . 
 the proposed endoscopic classification is practical and easily reproducible and provides valuable information regarding disease extension .