Extraperitoneal abdominopelvic inflammatory pseudotumor: report of four cases

Abstract

We describe four cases of inflammatory pseudotumor seen at our institution in the past 4 years. Four children were each found to have a large extraperitoneal mass on imaging studies, three of which were in the pelvis. Malignant sarcomatous tumors were suspected. Surgical biopsy of each mass, however, revealed inflammatory pseudotumor.

Abdominal inflammatory myofibroblastic tumor

“…Surgical excision has been the cornerstone of therapy because of the uncertainty in diagnosis, risk of disease progression, and lack of reliable alternative options [40]. Radiotherapy and chemotherapy have unclear roles as adjunctive modalities, but there are increasing reports of successful resolution with antibiotics, steroids, imatinib, or nonsteroidal anti-inflammatory drugs [41][42][43][44][45][46][47][48]. In our series, because tumor resection was considered mutilating and/or extensive, 2 patients (nos.…”

Mesenteric Inflammatory Pseudotumor: Unusual Presentation With Leukemoid Reaction and Massive Calcified Mass

“…There are no typical radiologic findings to distinguish it from other mass lesions (4). However, although the data regarding the computed tomography appearance of inflammatory pseudotumor are insufficient, it is usually observed as a slightly enhancing soft tissue mass (7,8). The calcification is a characteristic feature for some childhood malignant tumors such as neuroblastoma and teratoma.…”

Mesenteric inflammatory pseudo-tumour of the small intestine presenting with intestinal obstruction in a child: Case report and literature review

“…[6,11] Thus, while IP is generally accepted to be benign, multiple local recurrences, rarely encountered distant metastases, and tumour or complicated therapyrelated deaths suggest there is a spectrum of activity that lies somewhere between inflammation and neoplasia, [6,12] although there have been no reports of IP undergoing malignant change. [6,[12][13][14][15][16] Of particular clinical importance is the differential diagnosis of mesenteric IP from malignant mass lesions. Unfortunately, there are no specific or characteristic clinical/laboratory findings, including tumour markers and imaging modalities that can distinguish IP from other neoplasms, [11] with IP appearing on US and CT as a well-circumscribed mass of homogeneous echogenicity with soft tissue density displacing or invading adjacent tissues.…”

“…[6,10,12] Recurrences occurred within 1 year of initial surgery and were treated by re-resection. [10,13] It has also been described as being associated with distant metastases although these are rare, and probably more a consequence of multifocal incidence rather than classic malignant metastatic spread. [6,11] Thus, while IP is generally accepted to be benign, multiple local recurrences, rarely encountered distant metastases, and tumour or complicated therapyrelated deaths suggest there is a spectrum of activity that lies somewhere between inflammation and neoplasia, [6,12] although there have been no reports of IP undergoing malignant change.…”

“…[6,[10][11][12] Macroscopically, IP is a firm, well-circumscribed, non-encapsulated, yellow-white mass that commonly adheres to and infiltrates surrounding viscera. [6,13] Microscopically, it is characterized by spindle-shaped cells that are mixed with chronic inflammatory component consisting of plasma cells, lymphocytes, and occasional histiocytes. [6,10] IP can be differentiated from soft tissue sarcomas by the characteristic cellular heterogeneity, presence of mature polyclonal plasma cells, [11] and lymphocytes, and absent or rare anaplasia and mitotic figures.…”