cases were included if they had ultrasonographic evidence of a small intestinal circumferential thickening , mural mass , or mesenteric mass that subsequently was surgically removed by laparotomy and resection and anastomosis surgery or mesenteric mass removal . the histopathologic findings included focal to regional lipogranulomatous lymphangitis within the serosa , mucosa , mesentery , or some combination of these . all animals were clientowned dogs living within the greater philadelphia area and were assessed at one of the following specialty and emergency clinics : veterinary specialty and emergency center in langhorne , pa ; veterinary referral center and emergency service in malvern , pa ; veterinary specialty center of delaware in new castle , de ; and the center of animal referral and emergency services in langhorne , pa . information available from the 6 cases included signalment , presenting complaint , abdominal imaging findings , and clinicians ' differential diagnoses . clinical laboratory results and longterm outcomes were available for 5 of 6 cases ; 1 case was lost to followup . tissues were fixed in 10% buffered formalin , processed , embedded in paraffin , sectioned , and stained with hematoxylin and eosin ( h&e ) . cases were included if they had ultrasonographic evidence of a small intestinal circumferential thickening , mural mass , or mesenteric mass that subsequently was surgically removed by laparotomy and resection and anastomosis surgery or mesenteric mass removal . the histopathologic findings included focal to regional lipogranulomatous lymphangitis within the serosa , mucosa , mesentery , or some combination of these . all animals were clientowned dogs living within the greater philadelphia area and were assessed at one of the following specialty and emergency clinics : veterinary specialty and emergency center in langhorne , pa ; veterinary referral center and emergency service in malvern , pa ; veterinary specialty center of delaware in new castle , de ; and the center of animal referral and emergency services in langhorne , pa . information available from the 6 cases included signalment , presenting complaint , abdominal imaging findings , and clinicians ' differential diagnoses . clinical laboratory results and longterm outcomes were available for 5 of 6 cases ; 1 case was lost to followup . tissues were fixed in 10% buffered formalin , processed , embedded in paraffin , sectioned , and stained with hematoxylin and eosin ( h&e ) . breeds represented were as follows : bichon frise ( case 1 ) , harrier ( case 2 ) , bloodhound ( case 3 ) , maltese mix ( case 4 ) , mnsterlnder ( case 5 ) , and standard poodle ( case 6 ) . the median age at the time of diagnosis was 6.9  years ( range 310  years ) . histories of all patients included at least 3  weeks of signs of intraabdominal disease , including abdominal pain , diarrhea , vomiting , and weight loss . the longest history was that of dog 5 , which had a 2year history of intermittent abdominal pain and a previous endoscopic biopsy diagnosis of inflammatory bowel disease . presumably unrelated histories included dog bite wounds in the abdominal area 1  year before presentation in dog 1 , dirofilaria immitis diagnosis and treatment at a young age in dog 2 , and intermittent anal sacculitis in dog 6 . the most frequent presenting complaint was vomiting ( 4/6 ) , followed by intermittent abdominal pain ( 3/6 ) , weight loss ( 2/6 ) , diarrhea ( 2/6 ) , hypersalivation ( 1/6 ) , decreased appetite ( 1/6 ) , and stretching with head and thorax lower to the ground and abdomen and caudal end higher ( 1/6 ) . complete blood count and serum biochemistry results were available for 5/6 dogs , and all analytes were within normal reference ranges . specifically , total protein , albumin , globulin , and cholesterol concentrations , as well as lymphocyte counts , were within the reference range at initial presentation in all cases . two of the 6 dogs had urinalyses and sediment evaluation performed and no clinically relevant findings were reported . abdominal ultrasound examination was performed in all 6 dogs ; detailed reports were available for 5/6 dogs and the other had a short , concise report . four of the 6 dogs had circumferential muscularis thickening of the jejunum or ileum with no loss of wall layering ; 1 dog had a multilobulated , 3.0    2.0  cm , hypoechoic mass within the mesentery between caudal jejunal loops ; and 1 dog had a midjejunal , nonobstructive , asymmetrical , 1.39    0.52    3.75  cm , serosal mass with 4.07  cm of inspissated , hyperechoic omentum surrounding the area . one dog with muscularis thickening also had a focal isoechoic to mildly hyperechoic intramural mass that caused loss of wall layering . the circumferential thickening ranged from 0.7  cm to 1.0  cm and the distinct intestinal to mesenteric masses adjacent to the small intestine ranged in size from 3    2  cm to 4.07  cm in diameter . other areas examined were considered normal other than a small , singular hypoechoic nodule in the spleen of 2/6 dogs . based on ultrasonography , preoperative , 3view , thoracic radiographs were performed in 3/6 dogs ; no evidence of metastastic disease was present . preoperative thoracic radiographs and postoperative thoracic radiographs were performed in dog 5 : the preoperative radiographs were within normal limits and postoperative radiographs were performed after development of a cough and displayed a progressive , alveolar pattern in the left cranial lung lobe , right middle lung lobe , and right cranial lung lobe , which was interpreted to be bronchopneumonia presumably caused by postoperative aspiration . two dogs had abdominal radiographs performed before the ultrasound examination and both had gasfilled dilated loops of small intestine and dog 2 had an area of increased soft tissue or fluid opacity in the mesentery . no gastrointestinal lesions , including masses or dilated lymphatic vessels , were macroscopically evident other than in the section removed . all dogs recovered from anesthesia without complications other than dog 5 that developed and recovered from aforementioned aspiration pneumonia . histopathologic lesions were similar in all 6 dogs and affected the distal jejunum or ileum . the wall of the small intestine was markedly expanded by inflammation , dilated lymphatics , and fibrosis . the inflammation within and surrounding lymphatic vessels of the submucosa , muscularis , and serosa consisted of epithelioid and foamy macrophages , variable numbers of multinucleated giant cells , neutrophils , and lymphoplasmacytic infiltrates . most dogs ( 5/6 ) also exhibited lacteals dilated within the villi ( fig  1a ) , regions of necrosis ( 4/6 ) , and acicular cholesterol clefts within the granulomas ( 4/6 ) , some of which were phagocytized by macrophages ( fig  1b ) . dogs 1 , 2 , 4 , and 5 did not have any lesions within the marginal sections of the mass ; dog 5 also had stomach and duodenal fullthickness biopsies without any clinically relevant lesions . dog 3 had lymphatic lesions extending to the distal margin of the jejunal mass ; however , the proximal margin did not have any lesions . ( a ) the wall of the small intestine is markedly thickened by inflammation , fibrosis , lymphatic dilatation , and necrosis . the lacteals ( star ) in affected regions and lymphatic vessels within the submucosa and muscularis ( arrow ) are ectatic . the inflammation consists of a mixture of neutrophils , lymphocytes , and plasma cells , as well as numerous epithelioid macrophages and multinucleated giant cells ( arrow ) , which surround and engulf cholesterol clefts ( star ) . h & e. 200 ; bar  =  50  m . all dogs were discharged from the hospitals where surgery was performed , and clinical outcome was available for 5 of the 6 dogs ; case 3 was lost to followup . three of the 5 dogs ( dogs 1 , 2 , and 5 ) had longterm remission , defined as at least 11  months , of clinical signs with surgical intervention only . two episodes of abnormal behavior , interpreted as abdominal pain by the owner ( telephone communication ) , were reported but not confirmed by the veterinarian . dog 2 had an acute episode of vomiting 11  months after surgery , recovered with treatment consisting of fluids administered sc and famotidine , and then was lost to followup . it remains uncertain if the single vomiting episode was associated with recurrence of lipogranulomatous lymphangitis . dog 5 was doing well for more than 1  year after surgery with several repeated normal abdominal ultrasound examinations . however , 3  years after surgery , the dog developed severe abdominal pain , and an abdominal ultrasound examination showed thickening of the small intestinal , cecal and colonic walls , a focal intestinal wall mass ( 1.8    3.4  cm ) at the ileocecocolic junction , and mild peritoneal effusion . the dog 's serum albumin concentration at that time ranged from 1.7 to 2.2  g / dl ( reference range , 2.34.0  g / dl ) . the owner elected to not pursue surgery and the dog showed improvement with orally administered prednisolone for 8  months , at which time its appetite decreased . an additional ultrasound examination did not identify the previous ileocecocolic mass , but the dog was euthanized based on progressive nonspecific gastrointestinal signs and poor quality of life . the remaining 2 dogs ( dogs 4 and 6 ) did not have longterm remissions from their clinical signs . both dogs were started on dietary management , medical management , or both within 2  weeks of surgery . surgery was not performed , and medical and nutritional management was initiated : royal canin veterinary diet canine gastrointestinal low fat lf dry dog food,1 prednisolone , azathioprine , and psyllium . dog 6 has been maintained since surgery on a diet of boiled chicken , lowfat cottage cheese , pasta , and a variety of vegetables . the dog continues to have abdominal ultrasound examinations performed biannually with no recurrence of disease for 3  years postoperatively . four of the 6 affected dogs are known to be alive at the time of writing . breeds represented were as follows : bichon frise ( case 1 ) , harrier ( case 2 ) , bloodhound ( case 3 ) , maltese mix ( case 4 ) , mnsterlnder ( case 5 ) , and standard poodle ( case 6 ) . the median age at the time of diagnosis was 6.9  years ( range 310  years ) . histories of all patients included at least 3  weeks of signs of intraabdominal disease , including abdominal pain , diarrhea , vomiting , and weight loss . the longest history was that of dog 5 , which had a 2year history of intermittent abdominal pain and a previous endoscopic biopsy diagnosis of inflammatory bowel disease . presumably unrelated histories included dog bite wounds in the abdominal area 1  year before presentation in dog 1 , dirofilaria immitis diagnosis and treatment at a young age in dog 2 , and intermittent anal sacculitis in dog 6 . the most frequent presenting complaint was vomiting ( 4/6 ) , followed by intermittent abdominal pain ( 3/6 ) , weight loss ( 2/6 ) , diarrhea ( 2/6 ) , hypersalivation ( 1/6 ) , decreased appetite ( 1/6 ) , and stretching with head and thorax lower to the ground and abdomen and caudal end higher ( 1/6 ) . complete blood count and serum biochemistry results were available for 5/6 dogs , and all analytes were within normal reference ranges . specifically , total protein , albumin , globulin , and cholesterol concentrations , as well as lymphocyte counts , were within the reference range at initial presentation in all cases . two of the 6 dogs had urinalyses and sediment evaluation performed and no clinically relevant findings were reported . abdominal ultrasound examination was performed in all 6 dogs ; detailed reports were available for 5/6 dogs and the other had a short , concise report . four of the 6 dogs had circumferential muscularis thickening of the jejunum or ileum with no loss of wall layering ; 1 dog had a multilobulated , 3.0    2.0  cm , hypoechoic mass within the mesentery between caudal jejunal loops ; and 1 dog had a midjejunal , nonobstructive , asymmetrical , 1.39    0.52    3.75  cm , serosal mass with 4.07  cm of inspissated , hyperechoic omentum surrounding the area . one dog with muscularis thickening also had a focal isoechoic to mildly hyperechoic intramural mass that caused loss of wall layering . the circumferential thickening ranged from 0.7  cm to 1.0  cm and the distinct intestinal to mesenteric masses adjacent to the small intestine ranged in size from 3    2  cm to 4.07  cm in diameter . other areas examined were considered normal other than a small , singular hypoechoic nodule in the spleen of 2/6 dogs . based on ultrasonography , preoperative , 3view , thoracic radiographs were performed in 3/6 dogs ; no evidence of metastastic disease was present . preoperative thoracic radiographs and postoperative thoracic radiographs were performed in dog 5 : the preoperative radiographs were within normal limits and postoperative radiographs were performed after development of a cough and displayed a progressive , alveolar pattern in the left cranial lung lobe , right middle lung lobe , and right cranial lung lobe , which was interpreted to be bronchopneumonia presumably caused by postoperative aspiration . two dogs had abdominal radiographs performed before the ultrasound examination and both had gasfilled dilated loops of small intestine and dog 2 had an area of increased soft tissue or fluid opacity in the mesentery . no gastrointestinal lesions , including masses or dilated lymphatic vessels , were macroscopically evident other than in the section removed . all dogs recovered from anesthesia without complications other than dog 5 that developed and recovered from aforementioned aspiration pneumonia . histopathologic lesions were similar in all 6 dogs and affected the distal jejunum or ileum . the wall of the small intestine was markedly expanded by inflammation , dilated lymphatics , and fibrosis . the inflammation within and surrounding lymphatic vessels of the submucosa , muscularis , and serosa consisted of epithelioid and foamy macrophages , variable numbers of multinucleated giant cells , neutrophils , and lymphoplasmacytic infiltrates . most dogs ( 5/6 ) also exhibited lacteals dilated within the villi ( fig  1a ) , regions of necrosis ( 4/6 ) , and acicular cholesterol clefts within the granulomas ( 4/6 ) , some of which were phagocytized by macrophages ( fig  1b ) . dogs 1 , 2 , 4 , and 5 did not have any lesions within the marginal sections of the mass ; dog 5 also had stomach and duodenal fullthickness biopsies without any clinically relevant lesions . dog 3 had lymphatic lesions extending to the distal margin of the jejunal mass ; however , the proximal margin did not have any lesions . ( a ) the wall of the small intestine is markedly thickened by inflammation , fibrosis , lymphatic dilatation , and necrosis . the lacteals ( star ) in affected regions and lymphatic vessels within the submucosa and muscularis ( arrow ) are ectatic . the inflammation consists of a mixture of neutrophils , lymphocytes , and plasma cells , as well as numerous epithelioid macrophages and multinucleated giant cells ( arrow ) , which surround and engulf cholesterol clefts ( star ) . all dogs were discharged from the hospitals where surgery was performed , and clinical outcome was available for 5 of the 6 dogs ; case 3 was lost to followup . three of the 5 dogs ( dogs 1 , 2 , and 5 ) had longterm remission , defined as at least 11  months , of clinical signs with surgical intervention only . two episodes of abnormal behavior , interpreted as abdominal pain by the owner ( telephone communication ) , were reported but not confirmed by the veterinarian . dog 2 had an acute episode of vomiting 11  months after surgery , recovered with treatment consisting of fluids administered sc and famotidine , and then was lost to followup . it remains uncertain if the single vomiting episode was associated with recurrence of lipogranulomatous lymphangitis . dog 5 was doing well for more than 1  year after surgery with several repeated normal abdominal ultrasound examinations . however , 3  years after surgery , the dog developed severe abdominal pain , and an abdominal ultrasound examination showed thickening of the small intestinal , cecal and colonic walls , a focal intestinal wall mass ( 1.8    3.4  cm ) at the ileocecocolic junction , and mild peritoneal effusion . the dog 's serum albumin concentration at that time ranged from 1.7 to 2.2  g / dl ( reference range , 2.34.0  g / dl ) . the owner elected to not pursue surgery and the dog showed improvement with orally administered prednisolone for 8  months , at which time its appetite decreased . an additional ultrasound examination did not identify the previous ileocecocolic mass , but the dog was euthanized based on progressive nonspecific gastrointestinal signs and poor quality of life . the remaining 2 dogs ( dogs 4 and 6 ) did not have longterm remissions from their clinical signs . both dogs were started on dietary management , medical management , or both within 2  weeks of surgery . surgery was not performed , and medical and nutritional management was initiated : royal canin veterinary diet canine gastrointestinal low fat lf dry dog food,1 prednisolone , azathioprine , and psyllium . dog 6 has been maintained since surgery on a diet of boiled chicken , lowfat cottage cheese , pasta , and a variety of vegetables . the dog continues to have abdominal ultrasound examinations performed biannually with no recurrence of disease for 3  years postoperatively . four of the 6 affected dogs are known to be alive at the time of writing . this case series describes a focal manifestation of intestinal lipogranulomatous lymphangitis as a differential diagnosis in dogs with abdominal mass and normal hematology and serum biochemistry findings . there are several key differences in the clinical characteristics of these cases compared with previously reported cases of intestinal lymphangiectasia and lipogranulomatous lymphangitis . we report lesions that are focal to regional and form localized masses as opposed to disseminated small nodules . there was no laboratory evidence of ple on serum biochemistry at presentation , and no medical management was needed for months to years after surgical removal of the masses in most cases . some similarities of focal lipogranulomatous lymphangitis with lymphangiectasia compared to diffuse intestinal lymphangiectasia were also noted : both diseases affect primarily older animals , presented with vomiting , weight loss , and diarrhea , and both have unclear pathogeneses.1 , 2 , 3 in this case series , some of the animals affected with a localized lesion progressed to develop clinical signs and laboratory findings consistent with ple , indicating the possibility of disease progression . of diagnostic relevance , the specificity of abdominal ultrasound examination for the diagnosis of lipogranulomatous lymphangitis remains unclear . changes in echogenicity seen with classic forms of lymphangiectasia are seen with other inflammatory diseases.4 the lesions reported here are isoechoic to mildly hyperechoic or surrounded by a rim of hyperechogenicity . these findings differ from those of intestinal neoplasms , specifically adenocarcinoma and lymphoma , which are hypoechoic.6 therefore , the imaging features may be useful in prioritizing inflammation over neoplasia . given the complexity of the pathogenesis of inflammatory bowel disease , lymphangiectasia , and lymphangitis , the underlying cause for the focal nature of the lesions described in this case series remains unclear . lymphangitis can be seen with several intestinal diseases , including crohn 's disease in humans , in which lesions are more commonly found in portions of the intestinal tract in which lymphoid follicles are most numerous , and infrequently in regions with the poorest lymphatic supply.7 , 8 the lesions seen in our case series occurred in the distal small intestine , with 5/6 in the distal jejunum and 1 in the ileum , a site of numerous peyer 's patches . interestingly , the single case report of focal lymphangiectasia described a 7yearold west highland white terrier with no laboratory abnormalities and a 10cmlong circumferential mass within the ileum.5 
  in conclusion , we report a case series of dogs with large distal small intestinal masses found during abdominal ultrasound examination , diagnosed by biopsy with focal lipogranulomatous lymphangitis , and with no evidence of ple . the limitations of this study include the relatively small sample size , incomplete followup data in some cases , and lack of biopsies from other intestinal sites . complete surgical excision of the lesion , as well as fullthickness intestinal biopsies from sites distant from the mass , should be performed to confirm the focal nature of the lesion . focal lipogranulomatous lymphangitis is uncommon in dogs , but should be included as a differential diagnosis for an intestinal mural mass or mural thickening .
backgroundlipogranulomatous lymphangitis is inflammation of the intestinal lymphatic vessels and surrounding tissues caused by chronic leakage of lipidladen chyle . 
 grossly , lipogranulomas are typically disseminated small masses on the serosa and surrounding lymphatic vessels and consist of epithelioid macrophages , multinucleated giant cells , and cholesterol . 
 lipogranulomatous lymphangitis is occasionally seen in patients with lymphangiectasia and proteinlosing enteropathy ( ple).objectivesto characterize the historical features , clinical signs , treatment , histopathology , and outcome of dogs with focal lipogranulomatous lymphangitis.animalssix dogs with ultrasonographic evidence of focal , regional small intestinal masses , often with involvement of the adjacent mesentery , and a diagnosis of focal lipogranulomatous lymphangitis based on histopathology of biopsied masses.resultsthe median age of dogs was 6.9  years ( range 310  years ) . 
 all dogs had total protein , globulin , and albumin concentrations within the reference range at initial presentation and had intestinal masses identified on abdominal ultrasound examination . 
 histopathologic evaluation of lesions identified severe mural and mesenteric lipogranulomatous lymphangitis . 
 lymphangiectasia was noted in 5 cases and only in sections within the masslike lesion ; tissue without lipogranulomas had minimal lymphangiectasia , suggesting a localized phenomenon . 
 postoperative outcomes ranged from remission of clinical signs with no subsequent treatment for 1012  months in 2 dogs , postoperative management with medical and nutritional management in 3 dogs , and no outcome for 1 case.conclusions and clinical importancethis case series describes a unique masslike manifestation of intestinal lipogranulomatous lymphangitis and should be considered as a possible differential diagnosis in dogs with an intestinal mass .