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CASE REPORT Table of Contents   
Year : 2009  |  Volume : 52  |  Issue : 2  |  Page : 219-221
Inflammatory pseudotumor of the omentum: An uncommon pediatric tumor

1 Department of Pediatric Surgery, Chacha Nehru Bal Chikitsalaya, New Delhi, India
2 Department of Pathology, Maulana Azad Medical College, New Delhi, India
3 Department of Pathology, Chacha Nehru Bal Chikitasalya, Delhi, India

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Inflammatory pseudotumor is an uncommon tumor with a variable natural course. We report a case of omental pseudotumor in a 6-year-old male child. The child's clinical presentation was suggestive of an omental mass, which was operated upon after investigations. Histopathology revealed it to be an inflammatory pseudotumor. The case is presented for its unusual location.

Keywords: Inflammatory pseudotumor, omental tumor, pediatric

How to cite this article:
Gupta CR, Mohta A, Khurana N, Paik S. Inflammatory pseudotumor of the omentum: An uncommon pediatric tumor. Indian J Pathol Microbiol 2009;52:219-21

How to cite this URL:
Gupta CR, Mohta A, Khurana N, Paik S. Inflammatory pseudotumor of the omentum: An uncommon pediatric tumor. Indian J Pathol Microbiol [serial online] 2009 [cited 2022 Jul 7];52:219-21. Available from: https://www.ijpmonline.org/text.asp?2009/52/2/219/48924

   Introduction Top

Solid omental masses are an uncommon cause of abdominal lump in the pediatric age group. A case of inflammatory pseudotumor of the greater omentum, which has not been reported in the English literature to date, is described in the present report.

   Case Report Top

A 6-year-old male child presented with complaints of abdominal pain off and on for the last 1 year. The first episode of pain drew the parent's attention to the presence of an abdominal lump. The pain was relieved with symptomatic oral medications but the lump continued to increase in size. The child received empirical trial of antitubercular therapy for a month and a half that did not lead to any improvement. The child had low-grade fever, constipation and decreased appetite for 3 months before reporting to the hospital.

On examination, the child was pale. He had a temperature of 37.5° C and a clear chest on auscultation. Abdominal examination revealed a firm irregular, mildly tender, freely mobile lump of approximately 8cm ´ 8cm size in the epigastrium and umbilical region. The liver and spleen were not palpable. There was no free fluid. The genitalia and hernial sites were normal. Routine hematological investigations revealed a hemoglobin of 8.3gm% and total leucocyte count of 24,000/mm 3 , with relative lymphocytosis. Other routine hematological and biochemical investigations were normal.

An ultrasound study of the abdomen revealed a well-defined lobulated mass of size 5.5m ´ 3.6cm, with internal vascularity in the left lumbar region. Computed tomography of the abdomen [Figure 1] revealed a soft tissue mass in the left paraumblical region, suggestive of conglomerate lymph node mass and minimal ascites. Radiological investigations were suggestive of tuberculosis. Fine needle aspiration cytology [Figure 2] was suggestive of a mesenchymal tumor.

The child was taken up for exploratory laparotomy. A firm, lobulated mass was found in the greater omentum, distinct from the transverse colon and the surrounding structures [Figure 3a]. The mass was resected completely [Figure 3b]. Post-operative period was uneventful.

The histopathological examination reported a moderately cellular spindle cell lesion with scattered lymphocytes and inflammatory cells in a myxoid background [Figure 4a]. Immunohistochemical staining revealed diffuse positivity for actin [Figure 4b] and vimentin, suggestive of inflammatory fibroblastic tumor.

The child is well with no evidence of recurrence 1 year after surgery and is in follow-up.

   Discussion Top

Primary omental tumors are very uncommon. The true incidence of omental tumors is not known as not enough information is available in the English literature, which mainly consists of single case reports. A majority of these are leiomyosarcomas, leiomyomas and gastrointestinal stromal tumors reported in the 5 th -6 th decade of life. Primary omental tumors in children are rare and inflammatory pseudotumor of the omentum is even more uncommon.

Inflammatory pseudotumors have also been described as inflammatory fibrosarcoma, inflammatory myofibroblastic tumor, inflammatory myofibrohistiocytic proliferation, etc. They have no sexual predilection and are most common in the 2 nd decade of life. They are most common in the lung and in the orbit but have been reported from nearly every site in the body although the abdomen is an uncommon site. [1],[2] Symptoms depend on the site of the lesion. Patient may have associated fever, [3] anemia, elevated erythrocyte sedimentation rate, etc.

Clinically and radiologically, they resemble malignant tumors like sarcomas. [4] Histopathological examination reveals the presence of spindle cells, myofibroblasts, plasma cells, lymphocytes and histiocytes and they stain positive for actin, desmin and vimentin. [5,6] Computed tomography appearance is variable. The mass may be hypoattenuated or isoattenuated relative to muscle and enhance variably with contrast. [7] Magnetic resonance images are also variable. They are usually hypointense relative to skeletal muscle on T1-weighted images, hyperintense on T2-weighted images and heterogeneously enhance with contrast. [8]

The cause of these lesions is not known. Some authors believe it to be exaggerated response to tissue injury or infection due to the presence of inflammatory cells and association with trauma, surgery or other malignancy and presence of fever, elevated erythrocyte sedimentation rate, hypergammaglobulinemia, etc. [7],[9] Others believe it to be a low-grade sarcoma with inflammatory cells as it has a potential for local infiltration, recurrence, multicentricity and, rarely, metastases. [6] An immune mechanism has also been suggested due to reports of associated vasculitis, inferior vena cava thrombosis, sclerosing cholangitis, retroperitoneal fibrosis, etc. [10]

Genetic changes have also been implicated in its pathogenesis. [11] Complete surgical resection is the treatment of choice although spontaneous resolution has been reported in the lung and in the liver. High-dose corticosteroids are used in unresectable masses or for residual masses after resection. [3],[12] Radiotherapy is indicated where residual tumor is left or for orbital tumors not responding to steroids. The role of chemotherapy is controversial.

Recurrences have been documented in 18-40% of the cases. Recurrences are more common in extrapulmonary lesions, size more than 8 cm, locally invasive lesions and lesions showing hyperdiploidy. Overall mortality is reported to be 5-7% in cases with multiple recurrences. [9]

   Conclusion Top

Because the imaging and laboratory tests are non-specific, the diagnosis of inflammatory pseudotumor is rarely made before surgery. These benign but locally aggressive masses simulate malignancy in a majority of the cases. Inflammatory pseudotumour should, therefore, be considered when a mass arises in an unusual location in the pediatric age group. Complete surgical resection should be performed where possible and the child should be kept in long-term follow-up.

   References Top

1.Sawant S, Kasturi L, Amin A. Inflammatory myofibroblastic tumor. Indian J Pediatr 2002;69:1001-2.  Back to cited text no. 1  [PUBMED]  
2.Jain S, Bhargava SK, Upreti L, Mohta A. Inflammatory myofibroblastic tumor of sigmoid colon. Indian J Radiol Imaging 2004;14:103-4.  Back to cited text no. 2    Medknow Journal
3.Gulwani H, Chopra P. Inflammatory psedotumor of the lymphnodes presenting as pyrexia of unknown origin. Indian J Pathol Microbiol 2008;51:67-9.  Back to cited text no. 3  [PUBMED]  Medknow Journal
4.Bonnet JP, Basset T, Dijoux D. Abdominal inflammatory myofibroblastic tumors in children: Report of an appendiceal case and review of literature. J Pediatr Surg 1996;31:1311-4.  Back to cited text no. 4  [PUBMED]  
5.Scott L, Blair G, Taylor G, Dimmick J, Fraser G. Inflammatory pseudotumors in children. J Pediatr Surg 1988;23:755-8.  Back to cited text no. 5  [PUBMED]  [FULLTEXT]
6.Hedlund GL, Navoy JP, Galliani CA, Johnson WH Jr. Aggressive manifestations of inflammatory pulmonary pseudotumor in children. Pediatr Radiol 1999;29:112-6.  Back to cited text no. 6    
7.Slavotinek JP, Bourne AJ, Sage MR, Freeman JK. Inflammatory pseudotumor of the pancreas in a child. Pediatr Radiol 2000;30:801-3.  Back to cited text no. 7  [PUBMED]  [FULLTEXT]
8.Torzilli G, Inoue K, Midorikawa Y, Hui A, Takayama T, Makuuchi M. Inflammatory pseudotumors of the liver: prevalence and clinical impact in surgical patients. Hepatogastroenterology 2001;48:1118-23.  Back to cited text no. 8    
9.Sanders BM, West KW, Gingalewski C, Engum S, Davis M, Grosfeld JL. Inflammatory pseudotumor of alimentary tract: Clinical and surgical experience. J Pediatr Surg 2001;36:169-73.  Back to cited text no. 9  [PUBMED]  [FULLTEXT]
10.Stark P, Sandbank JC, Rudnicki C, Zahavi I. Inflammatory pseudotumor of the heart with vasculitis and venous thrombosis. Chest 1992;102:1884-5.  Back to cited text no. 10  [PUBMED]  [FULLTEXT]
11.Treissman SP, Gillis DA, Lee CL, Giacomantonio H, Resch L. Omental- mesenteric inflammatory pseudotumor: Cytogenetic demonstration of genetic changes and monoclonality. Cancer 1994;73:1433-7.  Back to cited text no. 11    
12.Mombaerts I, Schlingemann RO, Goldschmeding R, Koornneef L. Are systemic corticosteroids useful in management of orbital pseudotumors. Ophthalmology 1996;103:521-8.  Back to cited text no. 12  [PUBMED]  

Correspondence Address:
Anup Mohta
28-B, Pocket-C, SFS Flats, Mayur Vihar Phase - III, Delhi - 110 096
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0377-4929.48924

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  [Figure 1], [Figure 2], [Figure 3a], [Figure 3b], [Figure 4a], [Figure 4b]

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