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immunoglobulin g4-related disease ( igg4-rd ) is a very recently defined emerging entity characterized by a diffuse or mass forming inflammatory reaction rich in igg4-positive plasma cells associated with fibrosclerosis and obliterative phlebitis , and it is found to affect an increasing number of organs or systems ( 1 , 2 ) . we here report a case of diffuse pelvic peritoneal involvement by igg4-rd in a 57-year - old female presenting clinically with intestinal subocclusion . diffuse pelvic masses and nodules of various sizes were congregated in pelvic organs and showed delayed enhancement on enhanced ct .
some calcifications were also visible but the radiological differentiation from pelvic peritoneal carcinomatosis was not possible .
a 57-year - old female presented with a several - year history of unexplained dyspeptic symptoms .
numerous vague causes were suggested including oesophagitis due to a small hiatal hernia and treated with lansoprazole and dysfunction of the sphincter of oddi on the basis of a hepato - biliary scintigraphy ( data not shown ) . during the past year , the patient had experienced three acute episodes characterized by hypogastric colic pain followed colickly pain followed by alimentary - but occasionaly fecaloid - vomiting .
these episodes lasted for about 24 to 48 hours and ended by diarrheal debacle . during the last episode , the patient was admitted to the emergency room after the ending diarrheal debacle .
a new episode of abdominal pain compelled the patient to get readmitted to the emergency room .
laboratory test results indicated a mild inflammation with a crp level of 5.84 mg / l ( normal value : < 5 mg / l ) and a white blood cell count of 16200 units .
the middle and distal small bowel loops were distended along with the presence of hydroaeric levels .
the transitional level was found within the pelvic area , and the origin seemed to be related to diffuse peritoneal carcinomatosis including pelvic masses and nodules diffusely covering and encasing the gynecological structures , the terminal ileum and the pelvic folds .
some nodules were partially calcified and moderately enhanced on delayed contrast - enhanced ct scan .
an extensive surgical procedure was performed at one time including total radical hysterectomy , debulking , omentectomy , and resection of the ileo - cecal junction with resection of more than 30 centimeters of the terminal ileum .
1e , f ) showed numerous whitish nodules which extensively covered and invaded the gynecologic structures , the wall of the ileum and the mesenteric fat tissue .
the pattern of invasion was that of diffuse carcinomatosis . on sections , some of these nodules were found to deeply penetrate the entire bowel wall from the serosa to the mucosa ( fig .
1 h - k ) , these nodules showed areas of dense storiform fibrosis separated by areas of dense lymphoplasmacytic inflammatory infiltrate containing numerous normal plasma cells .
typical mild to moderate eosinophilia , germinal center formation and obliterative phlebitis were also detected .
the serum igg4 level was not assessed in the preoperative period , but it was found to be normal in the postoperative and follow - up periods .
the patient was treated by methylprednisolone with an initial dose of 32 mg per day .
this dose was reduced in a stepwise manner to 12 mg per day . due to persistent small peritoneal nodules in the right iliac fossa and in the pouch of douglas after six months ( data not shown ) , azathioprine at a dose of 100 mg daily was added .
concomitantly , the dose of methylprednisolone was gradually lowered to 2 mg per day . at one year of evolution ,
the association of igg4 with sclerosing diseases was first recognized in 2001 when hamano et al .
( 3 ) reported that patients with autoimmune pancreatitis ( aip ) had elevated serum igg4 levels . soon thereafter
, the examination of pancreatectomy specimens from patients with aip revealed the infiltration of the pancreas and surrounding tissues by increased numbers of igg4-positive plasma cells ( 1 ) .
immunoglobulin g4-related disease was recognized as a systemic disease since various extrapancreatic lesions were observed in patients with aip ( 1 , 2 , 4 - 6 ) . the real etiology and pathogenesis of igg4-rd is still not clearly understood ( 1 , 7 ) .
moreover the exact role of igg4 or igg4-positive plasma cells in this disease has not yet been elucidated . only some inconsistent biological features such as hypergammaglobulinemia or hypocomplementemia support the autoimmune nature of the disease process ( 7 ) .
various names have been ascribed to this clinicopathological entity including igg4-related sclerosing disease , igg4-related systemic sclerosing disease , igg4-related disease , igg4-related autoimmune disease , hyper - igg4 disease and igg4-related systemic disease ( 1 , 8) .
nevertheless , the current internationally accepted terminology is " igg4-rd " ( 9 ) . the recent increase in the number of reported cases of igg4-rd and autoimmune pancreatitis probably indicates an increase in the awareness and diagnosis of this entity on the basis of serum markers and igg4 immunostaining at biopsy rather than a real rise in its incidence ( 6 ) .
the extrapancreatic lesions of igg4-rd also exhibit the same characteristic histologic features including dense lymphoplasmacytic infiltrate , massive storiform fibrosis , and obliterative phlebitis as seen in igg4-related pancreatitis ( 1 , 9 ) . to date , numerous extrapancreatic organs and/or systems have been found to be affected by igg4-rd , and they may be divided into various anatomical locations including abdominal organs , thoracic organs , head and neck localization and miscellaneous presentations . most of these locations are summarized in table 1 ( 1 , 4 , 6 , 10 - 12 ) .
several associations with various malignancies have been reported sporadically , but further studies are needed in this area to determine if there is any causal relationship between the malignancies and igg4-rd ( 1 ) . currently , there is no published international consensus on the diagnostic criteria for igg4-rd ( 2 ) .
a raised serum igg4 level is not mandatory for the diagnosis but may be of valuable assistance ( 1 ) .
some authors have suggested that a serum igg4 concentration that is more than twice the upper limit of normal ( 2.8
not every entity with increased igg4 + plasma cells and a high igg4/igg ratio can be considered to belong to the igg4-rd spectrum .
most authors agree that a definitive diagnosis of igg4-rd requires histologic confirmation including the presence of characteristic histopathologic features such as dense lymphoplasmacytic infiltration , storiform fibrosis , obliterative phlebitis , mild to moderate eosinophilia and germinal center formation along with immunohistochemical staining demonstrating an increased number of igg4 + cells ( 2 , 7 , 9 ) . because our patient presented with signs of intestinal obstruction , this entity
however , in our patient , intestinal obstruction was caused by encasement of the pelvic organs by numerous peritoneal masses .
this feature is significantly different from that in sclerosing mesenteritis , in which fibrosis involves the retroperitoneum along the axis of the mesenteric vessels , a process which may secondarily cause intestinal obstruction by centripetal retraction and/or ischemia of the bowel by incarceration of its vessels .
patients with igg4-rd usually show a dramatic response to corticosteroid therapy , often within a few weeks , although spontaneous resolution may also occur . to date
, there is no consensus on the steroid therapy regimen or duration of treatment in igg4-rd . however , disease recurrence is common ( occurring in 20 - 40% of patients ) after stopping steroid treatment or during the steroid tapering period .
most clinicians administer a repeat course of corticosteroids with an immunomodulator such as azathioprine ( 1 , 7 ) . to the best of our knowledge ,
no case of igg4-rd primarily involving the peritoneum and mimicking peritoneal carcinomatosis has been reported previously . in the reported case ,
the differentiation of peritoneal igg4-rd from pelvic peritoneal carcinomatosis was unfortunately not possible with imaging and the final diagnosis was made by histopathology .
we hereby report a case of diffuse pelvic peritoneal involvement by immunoglobulin g4-related disease ( igg4-rd ) . 
 numerous pelvic masses and nodules showing delayed enhancement on enhanced abdominal ct were found to congregate in the pelvic organs of a 57-year - old female presenting with intestinal subocclusion . 
 the differentiation between peritoneal igg4-rd and pelvic peritoneal carcinomatosis was only made by histopathology and immunohistochemistry performed after surgical resection . 
 autoimmune pancreatitis represents the historical prototype of igg4-rd , but the spectrum of manifestations involving various organs has expanded during the last decade . in this report , we shortly review this clinical entity .