Introduction

Inflammatory pseudotumor (IPT) or nonspecific inflammatory mass is a benign tumor and represents a rare lesion with uncertain etiopathogenesis. Clinical symptoms of IPT are diverse and include presence of a mass, fever, weight loss, malaise, pain and site-specific symptoms. Histological characteristics of IPT include a heterogeneous population of acute and chronic inflammatory cells, particularly plasma cells, macrophages and fibroblasts, accompanied by areas of fibrosis and necrosis. IPT of the ileocecal junction and colon is an extremely rare condition. As exemplified by this case, in our country, a patient presenting with clinical features of right iliac fossa mass would on many occasions end up receiving antitubercular therapy. As was seen, there was little response to this therapy and the patient gained his health only after the mass lesion was removed surgically.

Case Report

A 68-year-old male presented to the outpatient department with complaints of abdominal bloating, constipation and decreased appetite of 6 months duration. He also reported weight loss of 18 kg during the same period. There was no history of fever, pain abdomen, vomiting, loose motions or gastrointestinal bleed. The patient did not report any history of diabetes, hypertension, thyroid disease, tuberculosis or surgery in the past. Clinical examination, done at an outside center, revealed a palpable mass in the right iliac fossa. Evaluation at that center revealed mild anemia (hemoglobin [Hb] 10.1 g/dL), normal white blood cell (WBC) count and platelet count. The erythrocyte sedimentation rate (ESR) at the end of 1st hour was 57 mm. The tests of liver function were normal. Viral screening for hepatitis B virus, hepatitis C virus and human immunodeficiency virus (HIV) was negative. The USG abdomen showed small mesenteric lymph nodes (3-5 mm in size, discreet), but otherwise was essentially normal.

The upper endoscopy done at that center was reported to be normal. Colonoscopy showed deformed ileocecal valve, ulceroproliferative growth in ascending colon and diminutive sigmoid polyp, which was not biopsied. The biopsy from the colonic growth was suggestive of chronic inflammation, with no positivity of acidfast bacilli (AFB) on special stains. Nevertheless, the patient was initiated on 4-drug antitubercular therapy (3RHEZ + 2RH). He received 5 months of this treatment, with little benefit. At this stage, a computed tomography (CT) enteroclysis was performed at that center (Fig. 1). This showed a long segment thickening of terminal ileum with involvement of ileocecal junction and dilated jejunum.

Long segment wall thickening of ascending colon with luminal narrowing was also noted. Significant paracolic and mesenteric fat streaking was noted. Mesenteric lymph nodes were seen to be enlarged and there was presence of minimal ascites. He was referred to our center with the above background. On examination, his vitals were normal. He was esthetically built. He had mild pallor, but rest of the general physical examination was unremarkable. Per abdomen examination revealed a palapable mass of size 6 × 4 cm in the right iliac fossa, with limited mobility. Evaluation revealed Hb - 11 g/dL, total leukocyte count (TLC) - 6,500/mm3, platelets - 2.35 lacs/mm3, serum bilirubin - 0.8 mg/dL, alanine transaminase (ALT) - 60 IU/L, aspartate transaminase (AST) - 50 IU/L, alkaline phosphatase (ALP) - 102 IU/L, serum proteins - 6.8 g/dL with serum albumin - 3.0 g/dL.

A chest X-ray was done and found to be normal. The CT films were reviewed at our center, and it was decided to subject the patient to diagnostic laparoscopy. Intraoperative findings were: Thickening ileocecal region with pulled up cecum, firm cecal mass with dense adhesions to proximal small bowel, thickened mesentery and minimal ascites (Fig. 2).

The surgeons proceeded with right hemicolectomy. His postoperative course was uneventful. Gross examination of the resected segment revealed constriction of ileocecal junction with ulcerated mucosa and thickened wall forming ill-defined mass measuring 7 × 6 × 6 cm in size (Fig. 3).

On cut section, the wall of the mass was seen to be composed of white fibrous tissue. Histological examination of the resected segment showed inflamed mucosa with ulceration and denudation with prominent lymphoplasmacytic infiltrate (Fig. 4). The submucosa showed presence of fibrosis, congested blood vessels (Fig. 5), scattered smooth muscle bundles, lymphocytic infiltration with attempt to lymphoid aggregate formation (Fig. 6). There was no evidence of classic epithelioid granulomas (Figs. 7 and 8). Two of the 15 resected lymph nodes showed foreign body giant cell reaction (Fig. 9).

AFB was not seen on special stains and polymerase chain reaction (PCR) for Mycobacterium tuberculosis was negative. Fungal stains were unremarkable and there was no evidence of malignancy. His serum immunoglobulin G4 (IgG4) was done after review of the histology of this lesion and was not elevated.

Immunohistochemical staining was strongly positive for smooth muscle antibody (SMA) and weakly positive for desmin (Figs. 10 and 11). This clinical and histological picture suggested the diagnosis of inflammatory mass of ileocecal region of nonspecific origin (IPT). After the surgery, the patient has been symptom free and has gained weight, with normal haematological and biochemical parameters.

Discussion

Inflammatory pseudotumor or nonspecific inflammatory mass, has most commonly been reported in the lung. There have been cases reported of its presence in the central nervous system, major salivary glands, kidneys, liver, omentum, ovary, larynx, urinary bladder, breast, pancreas, spleen, lymph nodes, skin, soft tissues and orbit.1-3 IPT is a benign tumor and represents a rare lesion with uncertain etiopathogenesis. Clinical symptoms of IPT are diverse, and include presence of a mass with fever, weight loss, malaise, pain and site-specific symptoms. Microorganisms including Bacteroides spp., Actinomycetes, Klebsiella, Escherichia coli, Grampositive cocci, b-hemolytic Streptococcus and M. tuberculosis have been found in many reports of IPT.4,5 However, in other reports of IPT, no causative microorganisms were found and an association between IPT and hepatopancreatobiliary autoimmune diseases, such as IgG4 cholangiopathy/pancreatitis, sclerosing cholangitis was suggested.6 In the case reported here, there was no past history suggestive of autoimmunity and IgG4 was within normal limits.

Histological characteristics of IPT include a heterogeneous population of acute and chronic inflammatory cells, particularly plasma cells, macrophages and fibroblasts, accompanied by areas of fibrosis and necrosis. The microscopic appearance varies from case to case. This entity has been given many different names, including plasma cell granuloma, inflammatory myofibroblastic tumor and most commonly IPT.7 IPT of the ileocecal junction and colon is an extremely rare condition, with only a handful of case reports. This unexpected lesion tends to raise an erroneous impression of malignancy.8

As exemplified by this case, in our country, a patient presenting with clinical features of right iliac fossa mass would on many occasions, end up receiving antitubercular therapy. As was seen, there was little response to this therapy and the patient gained his health only after the mass lesion was removed surgically.

References

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