Hepatic inflammatory pseudotumor: case report, review of the literature, and a proposal for morphologic classification

Abstract

Inflammatory pseudotumors (IPT) are uncommon mass lesions arising most typically in the lungs of young adults. These tumors are so named because of the difficulty in distinguishing them preoperatively from malignant lesions. IPT are characterized histologically by localized fibrous proliferations with infiltration by mononuclear leukocytes, particularly plasma cells. Seventeen previous cases of IPT involving the liver and biliary tree have been reported in children. In this location, IPT may lead to biliary obstruction, portal hypertension, cirrhosis and eventually hepatic failure. We describe the youngest patient ever reported with hepatic IPT (HIPT) and biliary obstruction, who was successfully managed with a left hepatic lobectomy and Kasai portoenterostomy. Based on all previous cases of HIPT in both adults and children (74 cases), we propose a morphologic classification of these lesions based on the presence of single versus multiple lesions, with individualized management. Type 1 lesions are large, solitary lesions, often with central necrosis, giving a characteristic radiographic appearance. Type 2 lesions are multiple smaller, solid nodules indistinguishable from metastatic malignancy.

Abdominal inflammatory masses mimicking neoplasia in children—experience of two centers

“…In children, these tumors are typically localized in the liver, intestinal mesentery, or retroperitoneum, including the pelvis (especially the bladder). In the past these lesions seemed to be very unusual in children, but judging from recently emerging reports, they have been identified more frequently than previously thought [1][2][3][4][5][6][7][8]. However, their etiology is still obscure, and no clear causative factors have been identified.…”

“…Plasma cells often predominate, but inconsistent proportions of lymphocytes (including lymphoid follicles), neutrophils, eosinophils, macrophages, and oval to spindle-shaped stromal cells have been found [2][3][4][5][6][7][8][9][10][11][12][13][14]. Inflammatory infiltrate can be confused with lymphomas or granulomatous lesions, especially if multinucleated giant cells and foamy histiocytes are found [2][3][4][5][6][7][8][9][10][11][12][13][14]. The stroma is typically quite fibrotic with a laminated appearance or dense sclerotic zones, which can be confused with sarcomas.…”

“…The stroma is typically quite fibrotic with a laminated appearance or dense sclerotic zones, which can be confused with sarcomas. Myxoid foci may be present, but the vascular component is minimal [2][3][4][5][6][7][8][9][10][11][12][13][14]. Stromal cells usually have typical, immunohistochemical, and ultrastructural features of proliferating myofibroblasts, and for this reason IPTs are currently classified (according to the World Health Organization) as inflammatory myofibroblastic tumors [1][2][3][4][5][6][7][8][9].…”

“…Inflammatory pseudotumors (IPTs) are the most common among such processes. They are usually found in children and young adults and are most frequently found in the lungs, but they can occur in almost any organ, especially within the abdomen [1][2][3][4][5][6][7][8].…”

Nonresectable inflammatory pseudotumor of the porta hepatis

“…It has been demonstrated in a variety of tissues and organs, including the ureter, kidney, stomach, and lung [1][2][3][4], and is often mistaken for a malignancy. There have been 18 reported pediatric cases of inflammatory pseudotumors of the liver reported in the medical literature [5,6]. Treatment for hepatic pseudotumors has traditionally consisted of surgical resection of the mass with postoperative antibiotics.…”