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Year : 2022  |  Volume : 65  |  Issue : 3  |  Page : 683-685
IgG4 related sclerosing encapsulating peritonitis with cocoon formation: An unusual and undescribed presentation

1 Department of Histopathology, Sir Gangaram Hospital, New Delhi, India
2 Department of Surgical Gastroenterology and Liver Transplantation, Sir Gangaram Hospital, New Delhi, India

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Date of Submission20-Jun-2021
Date of Decision20-Nov-2021
Date of Acceptance22-Feb-2022
Date of Web Publication21-Jul-2022


IgG4-related sclerosing mesenteritis is a rare disease of mesentery of an unknown etiology which shows a constellation of histopathologic findings of lymphoplasmacytic inflammation with IgG4-positive plasma cells and marked fibrosis. This chronic inflammatory condition of mesentery forming an abdominal cocoon has never been described before to the best of our knowledge. Here, we report a patient with a history of subacute small bowel obstruction who was found to have an intra-abdominal encapsulating mass in the right iliac fossa and was finally diagnosed as IgG4-related sclerosing encapsulating peritonitis (abdominal cocoon) based on peroperative findings, histology and immunohistochemistry.

Keywords: Abdominal cocoon, IgG4-related disease, sclerosing encapsulating peritonitis

How to cite this article:
Osama MA, Roy S, Rawat S, Rao S. IgG4 related sclerosing encapsulating peritonitis with cocoon formation: An unusual and undescribed presentation. Indian J Pathol Microbiol 2022;65:683-5

How to cite this URL:
Osama MA, Roy S, Rawat S, Rao S. IgG4 related sclerosing encapsulating peritonitis with cocoon formation: An unusual and undescribed presentation. Indian J Pathol Microbiol [serial online] 2022 [cited 2022 Aug 15];65:683-5. Available from: https://www.ijpmonline.org/text.asp?2022/65/3/683/351610

   Introduction Top

IgG4-related disease (IgG4-RD) is an idiopathic multiorgan inflammatory disorder that is characterized by elevated serum IgG4 concentrations in majority of cases.[1] This condition predominantly affects men between 50 and 70 years of age. The most commonly affected organs include the pancreas, retroperitoneum, parotid and lacrimal glands with few cases involving the kidneys, gastrointestinal tract and spleen.[2] IgG4 related sclerosing mesenteritis/peritonitis (IgG4-SM/SP) is a rare presentation in IgG4-RD spectrum and primarily involves the small-bowel mesentery/peritoneum. It is characterized by chronic inflammation, fibrosis and fat necrosis. Sclerosing encapsulating peritonitis (SEP) occurs when loops of the bowel are encased within the peritoneal cavity by a membrane, leading to intestinal obstruction. Although cocooning of the abdomen is secondarily seen with multiple causes including abdominal tuberculosis, malignancy, peritoneal dialysis, trauma related, recurrent peritonitis etc.; however, IgG4 related cocoon formation has not been described in the literature.

   Case History Top

A 53-year-old man presented with abdominal pain and vomiting. He had a history of umbilical hernioplasty. CT scan revealed adhered ileal loops with thickened peritoneum forming a cocoon [Figure 1]a. Proximal jejunal loops were dilated suggesting subacute intestinal obstruction [Figure 1]b. Clinico-radiological differentials included dermoid tumor, gastrointestinal stromal tumor and bezoar. Following which, laparotomy with adhesiolysis and excision of cocoon was done [Figure 1]c. Cocoon wall was sent for histopathological examination. Grossly, we received multiple flattened whitish tissue pieces together measuring 10 × 10 cm. The wall thickness of these pieces varied from 0.2 to 0.5 cm. Microscopic examination revealed wall-like tissue pieces composed of dense fibrocollagenous tissue without any epithelial lining [Figure 2]a. Moderately dense chronic inflammatory cell infiltrate, comprising of lymphocytes and plasma cells, was arranged in a linear fashion along one surface of the pieces with few scattered lymphoid follicles [Figure 2]a and [Figure 2]b. Focal fat necrosis with calcification was noted [Figure 2]c. On immunonhistochemistry (IHC), IgG4 positive plasma cells were 30-40/HPF [Figure 3] and IgG4/IgG ratio was >30%. No vascular changes were observed. Based on these features, possibility of IgG4-related SEP (with cocooning) was suggested and correlation with clinical and biochemical findings was advised. Biochemical tests done thereafter showed IgE levels of 265.8 IU/mL (normal <150 mg/dL); IgG levels of 1382 mg/dL (normal 540–1822 mg/dL); IgG4 levels of >250 mg/dL (normal 10–120 mg/dL), thus confirming the diagnosis of IgG4-SEP. Further postoperative examination showed no evidence of IgG4-RD of other organs. The patient was started on long-term steroids and immunomodulators and during a follow-up of 1.5 years, there has been no evidence of disease recurrence or symptom relapse.
Figure 1: (a) Oral contrast-enhanced abdominal CT scan. Coronal image showing clumping of ileal loops with thickened peritoneum surrounding it (cocoon formation); (b) Oral contrast-enhanced abdominal CT scan. Axial image showing dilated bowel loops and thickened mesentery; (c) Intraoperative picture of the abdominal cocoon

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Figure 2: (a) Dense fibrocollagenous tissue showing plasma cells and lymphocytes arranged in a linear fashion along one surface (HE 200×); (b) Scattered lymphoid follicle with diffuse lymphoplasmacytic infiltrate in sclerotic tissue (HE 200×); (c) Focal fat necrosis with dystrophic calcification (marked by arrow) (HE 100×)

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Figure 3: IHC staining showing numerous IgG4-positive plasma cells (>30/HPF) (400×)

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   Discussion Top

Sclerosing mesenteritis is a rare disease and was first described by Sulla in 1924 as “retractile mesenteritis”.[3] The prevalence of SM varies from 0.16% to 7.8%;[4] however, the incidence of SM related to IgG4-RD has not been determined. This condition can lead to a variety of nonspecific symptoms including abdominal pain, nausea, vomiting, weight loss and fever. Our patient had similar complaints of recurrent abdominal pain and vomiting. Emory et al.[5] in their review of 84 cases of SM, showed 4 cases with a history of previous trauma or surgery. Our patient has also had a history of umbilical hernioplasty few years back. Radiographic studies are nonspecific and usually show a well/ill-defined mass in the mesentery that may be clinically misdiagnosed as a malignant neoplasm.[6] The diagnosis can only be established after an operative workup along with a generous biopsy. IgG4-RD is a systemic syndrome characterized by masses in various organs infiltrated by IgG4-positive plasma cells and high serum IgG4 concentrations.[7],[8] Definite diagnostic criteria are discussed in [Table 1].[9] IgG4-related SM is diagnosed only when apart from diffuse fibrotic thickening of mesentery, histologic and immunologic features satisfy the criteria of IgG4-RD. Abdominal cocooning or SEP is characterized by encapsulation of the small bowel by a thick, fibrous membrane leading to small bowel obstruction. There are quite a number of cases of IgG4 related SM as well as non-IgG4 related SEP in the literature. However, on extensive search on PubMed using keywords like 'IgG4 related SEM/SEP' or 'IgG4-RD with abdominal cocoon', not a single case was retrieved. Hence, we are documenting the first case of IgG related SEP which presented with an abdominal cocoon.
Table 1: The 2020 Revised comprehensive diagnostic criteria for IgG4-related disease[9]

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There is no unanimity regarding the treatment of IgG4-SM. Both medical therapy and surgical therapy have shown acceptable response rates, however, the limited number of cases make it difficult to determine a gold standard treatment.[10] In the present case, after the surgical excision of the mass, the patient was started on deflazacort and mycophenolate mofetil and is managing very well so far without any recurrence.

Pathologic diagnosis is important in SEP to exclude possibility of malignancy and other non-IgG4 related causes.

   Conclusion Top

Recognition of the IgG4-RD in case of SM is important for its clinical implications and to determine the therapeutic approach. In view of its systemic nature, involvement of other associated organs need to be investigated. Role of medication apart from surgical intervention mandates its diagnosis so as to provide appropriate treatment and management to the patients. The rarity of the disease limits its clear characterization; hence large cases series are needed for improving the understanding of this entity. In spectrum of IgG4-SM, the encapsulating involvement of peritoneum leading to an abdominal cocoon formation has not been described in the published literature so far.

Declaration of patient consent

The authors certify that they have obtained the appropriate consent from the patient. The patient has given his consent for the images and other clinical information to be reported in the journal. The patient understands that the name and initials will not be published, and due efforts have been made to conceal the same.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

   References Top

Stone JH, Chan JK, Deshpande V, Okazaki K, Umehara H, Zen Y, et al. IgG4-related disease. Int J Rheumatol 2013;2013:532612.  Back to cited text no. 1
Inoue D, Yoshida K, Yoneda N, Ozaki K, Matsubara T, Nagai K, et al. IgG4-related disease: Dataset of 235 consecutive patients. Medicine (Baltimore) 2015;94:e680.  Back to cited text no. 2
Jura V. Sulla mesenterite e sclerosante. Policlinico (Sezprat) 1924;31:575-81.  Back to cited text no. 3
Sharma P, Yadav S, Needham CM, Feuerstadt P. Sclerosing mesenteritis: A systematic review of 192 cases. Clin J Gastroenterol 2017;10:103-11.  Back to cited text no. 4
Emory TS, Monihan JM, Carr NJ, Sobin LH. Sclerosing mesenteritis, mesenteric panniculitis and mesenteric lipodystrophy: A single entity? Am J Surg Pathol 1997;21:392-8.  Back to cited text no. 5
Levy AD, Rimola J, Mehrotra AK, Sobin LH. From the archives of the AFIP: Benign fibrous tumors and tumorlike lesions of the mesentery: Radiologic-pathologic correlation. Radiographics 2006;26:245-64.  Back to cited text no. 6
Chen TS, Montgomery EA. Are tumefactive lesions classified as sclerosing mesenteritis a subset of IgG4-related sclerosing disorders? J Clin Pathol 2008;61:1093-7.  Back to cited text no. 7
Nomura Y, Naito Y, Eriguchi N, Kume T, Itai N, Sonoda H, et al. A case of IgG4-related sclerosing mesenteritis. Pathol Res Pract 2011;207:518-21.  Back to cited text no. 8
Umehara H, Okazaki K, Kawa S, Takahashi H, Goto H, Matsui S, et al. The 2020 Revised comprehensive diagnostic (RCD) criteria for IgG4-RD. Mod Rheumatol 2021;31:529-33.  Back to cited text no. 9
Kerdsirichairat T, Mesa H, Abraham J, Viskocil K. Sclerosing mesenteritis and IgG4-related mesenteritis: Case series and a systematic review of natural history and response to treatments. Immunogastroenterology 2013;2:119-28.  Back to cited text no. 10

Correspondence Address:
Seema Rao
Department of Histopathology, Sir Gangaram Hospital, New Delhi - 110 060
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ijpm.ijpm_637_21

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  [Figure 1], [Figure 2], [Figure 3]

  [Table 1]


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