Inflammatory pseudotumor of lymph nodes: a study of 25 cases with emphasis on morphological heterogeneity

Controversies in the Spleen: Histiocytic, Dendritic, and Stromal Cell Lesions

Histiocytic, dendritic, and stromal cell lesions that occur in the spleen are challenging diagnostically, not well studied due to their rarity, and therefore somewhat controversial. New techniques for obtaining tissue samples also create challenges as splenectomy is no longer common and needle biopsy does not afford the same opportunity for examination of tissue. Characteristic primary splenic histiocytic, dendritic, and stromal cell lesions are presented in this paper with new molecular genetic findings in some entities that help differentiate these lesions from those occurring in non-splenic sites, such as soft tissue, and identify possible molecular markers for diagnosis.

Fibrosing Inflammatory Pseudotumor Presenting as Cranial Neuropathy

We report two cases of biopsy-corroborated “fibrosing inflammatory pseudotumor” to illustrate that the entity, rarely described in the neurological literature, should be included in the differential diagnosis of either a cranial mononeuropathy or, certainly, in the case of progressive cranial neuropathies. A broad differential diagnosis arises in certain contexts. Early steroid treatment can be effective, and perhaps later-generation immune-modulating agents may confer further options, although there is no known definitive treatment.

Clinicopathological differential diagnosis of IgG4-related disease: A historical overview and a proposal of the criteria for excluding mimickers of IgG4-related disease

IgG4-related disease (RD) is a relatively new entity, which was first proposed in 2001. Since then, clinical and pathological characteristics of the disease have been investigated. As IgG4-RD has been studied extensively, the diagnostic criteria for IgG4-RD of each organ and the comprehensive diagnostic criteria for IgG4-RD have also been developed. However, one of the biggest challenges in the field is distinguishing between IgG4-RD and mimickers, which show overlapping features with IgG4-RD. It is now known that some non-IgG4-RDs may meet the diagnostic criteria of IgG4-RD and can be misdiagnosed as IgG4-RD. However, accurate diagnosis is crucial, as the treatments for IgG4-RD and those for other diseases that may be misdiagnosed as IgG4-RD are different. This prompted us to create and propose comprehensive exclusion criteria for IgG4-RD. In this review, we have described the comprehensive exclusion criteria for IgG4-RD, with a historical overview of the disease. These exclusion criteria were recently created by the Research Program for Intractable Disease of the Ministry of Health, Labor, and Welfare of Japan, All Japan IgG4 team, to support correct and accurate diagnosis of IgG4-RD.

The great mimicker: a rare case of head and neck inflammatory pseudotumour in the presence of human immunodeficiency virus

BACKGROUND

Inflammatory pseudotumours of the head and neck are rare. A connection has been made between inflammatory pseudotumours and human immunodeficiency virus positivity.

CASE REPORT

This paper reports a case of an inflammatory pseudotumour presenting with a lesion in the left tonsil and left cervical lymph node in a 49-year-old human immunodeficiency virus positive patient. A histological diagnosis was obtained after biopsy and serial radiological imaging.

CONCLUSION

Diagnostic uncertainties can lead to unnecessary surgery. It is important to recognise the clinical, radiological and histological indicators of an inflammatory pseudotumour to enable a timely diagnosis and arrange appropriate treatment. In patients with co-morbidities causing immunocompromise, the potential diagnosis of an inflammatory pseudotumour should be considered. This is especially the case in human immunodeficiency virus patients, as inflammatory pseudotumours have been associated with immune reconstitution inflammatory syndrome, which can manifest up to several years after the initiation of, or change in, antiretroviral therapies.

Concomitant occurrence of Mikulicz's disease and immunoglobulin G4-related chronic rhinosinusitis: a clinicopathological study of 12 cases

AIMS

Concomitant occurrence of Mikulicz's disease (MD) and immunoglobulin (Ig)G4-related chronic rhinosinusitis (IgG4-related CRS) is extremely rare. We evaluated the clinicopathological features of MD patients with concomitant IgG4-related CRS (CRS-MD).

METHODS AND RESULTS

Twelve CRS-MD patients were evaluated clinically and biopsy samples were taken from the lacrimal/salivary glands (n = 12) and nasal mucosa (n = 7) for assessment of IgG4-positive cells, using immunohistochemical techniques. Similarly, nine MD patients and 10 patients with common CRS were evaluated as controls. CRS-MD patients had higher serum IgG and IgG4 concentrations than MD patients (P < 0.05 for both). Lymphoplasmacytic infiltration, lymphoid follicle formation and sclerosis was prominent in the lacrimal/salivary glands in both groups; however, the magnitude of IgG4-positive plasma cells infiltration in the CRS-MD group was significantly higher compared to the MD group (P = 0.004). Similarly, evaluation of nasal mucosa revealed greater lymphocyte, plasma cell and eosinophil infiltration and lymphoid follicle formation, together with significantly higher IgG4-positive plasma cell infiltration in the CRS-MD group compared to the common CRS group (P = 0.004).

CONCLUSIONS

Concomitant MD and IgG4-related CRS were characterized by a combination of IgG4-positive plasma cells infiltration in the lacrimal/salivary glands and the nasal mucosa and increased serum IgG4.

IgG4-related disease-like fibrosis as an indicator of IgG4-related lymphadenopathy

The significance of IgG4-related diseases including IgG4-related lymphadenopathy has recently been recognized worldwide. Inflammatory pseudotumors in lymph nodes, as well as in other organs, are also recognized as IgG4-related diseases. Only a few case reports have described IgG4-related lymphadenopathy with fibrosis (IgG4-fibrosing lymphadenopathy), and IgG4-fibrosing lymphadenopathy has not been compared clinicopathologically with non-IgG4-related lymphadenopathy with fibrosis. We have evaluated the pathologic features in 13 patients with IgG4-fibrosing lymphadenopathy, including IgG4 and IgG expression in lymph nodes, and compared these features with those of patients with non-IgG4-related lymphadenopathy with fibrosis with reactive inguinal lymphadenopathy and focal fibrosis and lymph nodes at least 10 mm in diameter. IgG4-fibrosing lymphadenopathy was characterized by lymphoplasmacytic and eosinophilic infiltration, many IgG4-positive plasma cells in fibrotic areas, and high serum IgG4 concentrations. The IgG4-positive/IgG-positive plasma cell ratio was significantly higher in the IgG4-fibrosing lymphadenopathy than in the non-IgG4-fibrosing lymphadenopathy group. The presence of even minor fibrosis with characteristics of IgG4-related disease such as IgG4-fibrosing lymphadenopathy may facilitate the diagnosis of IgG4-related lymphadenopathy.

IgG4-Related Lymphadenopathy

Lymphadenopathy is frequently observed in patients with immunoglobulin G4-related disease (IgG4-RD) and sometimes appears as the first manifestation of the disease. The diagnosis of IgG4-related lymphadenopathy is complicated owing to a great histological diversity, with at least 5 histological subtypes. Indeed, lymph node biopsy may be performed under the suspicion that the lymphadenopathy is a malignant lymphoma or other lymphoproliferative disorder. The diagnosis of IgG4-RD is characterized by both elevated serum IgG4 (>135 mg/dL) and histopathological features, including a dense lymphoplasmacytic infiltrate rich in IgG4(+) plasma cells (IgG4(+)/IgG(+) plasma cell ratio >40%). However, patients with hyper-interleukin (IL-) 6 syndromes such as multicentric Castleman's disease, rheumatoid arthritis, and other immune-mediated conditions frequently show lymph node involvement and often fulfill the diagnostic criteria for IgG4-RD. Owing to these factors, IgG4-RD cannot be differentiated from hyper-IL-6 syndromes on the basis of histological findings alone. Laboratory analyses are crucial to differentiate between the 2 diseases. Hyper-IL-6 syndromes are characterized by elevated serum levels of IgG, IgA, IgM, and C-reactive protein (CRP); thrombocytosis; anemia; hypoalbuminemia; hypocholesterolemia. In contrast, IgG4-RD does not share any of these characteristics. Therefore, the diagnosis of IgG4-RD requires not only pathological findings but also clinical and laboratory analyses.

Fibroblastic and myofibroblastic tumors in children and adolescents

Fibroblastic and myofibroblastic tumors in children and adolescents are a relatively common group of soft tissue proliferations that range from reactive to hamartomatous to neoplastic, with a full spectrum of benign, intermediate, and malignant neoplasms. These lesions are diagnostically challenging because of morphologic and immunohistochemical overlap, despite significant clinical, genetic, and prognostic differences. The fibromatoses are a major subgroup, and all types of fibromatoses can occur in the 1st 2 decades of life. Intermediate and malignant fibroblastic-myofibroblastic tumors are an important group that includes variants of fibrosarcoma and other tumors with recurrent cytogenetic or molecular genetic abnormalities and low metastatic potential. Pathologic examination is enhanced by adjunct techniques, such as immunohistochemistry, cytogenetics, and molecular genetics, although morphology provides the ultimate criteria for a specific diagnosis. This article reviews the clinicopathologic features of fibroblastic and myofibroblastic tumors with an emphasis on the unique aspects of these neoplasms in children and adolescents, the use of diagnostic adjuncts, and differential diagnoses.

Primary IgG4-related lymphadenopathy with prominent granulomatous inflammation and reactivation of Epstein-Barr virus

We report a unique case of primary IgG4-related lymphadenopathy showing prominent granulomatous inflammation and Epstein-Barr virus (EBV) reactivation. Involved lymph nodes showed an expanded interfollicular zone with prominent granulomatous inflammation, including a predominance of epithelioid macrophages and occasional Langhans multinucleated giant cells. Bundles of spindle cells were also observed. Intermingled with the granulomatous inflammation were numerous mature plasma cells, eosinophils, and neutrophils. The percentage of IgG4+/IgG+ plasma cells was markedly elevated (70%), along with raised serum IgG4 levels. The plasma cells did not show immunoglobulin light-chain restriction. EBV-positive lymphocytes were scattered throughout the paracortical areas. Corticosteroid treatment was very effective. IgG4-related lymphadenopathy has a broad histological spectrum and might be misdiagnosed due to other conditions which morphologically closely resemble it. The correct diagnosis is important in view of the remarkable response to steroid therapy.

IgG4-related sclerosing disease, an emerging entity: a review of a multi-system disease

Immunoglobulin G4-related systemic disease (IgG4-RSD) is a recently defined emerging entity characterized by a diffuse or mass forming inflammatory reaction rich in IgG4-positive plasma cells associated with fibrosclerosis and obliterative phlebitis. IgG4-RSD usually affects middle aged and elderly patients, with a male predominance. It is associated with an elevated serum titer of IgG4, which acts as a marker for this recently characterized entity. The prototype is IgG4-related sclerosing pancreatitis or autoimmune pancreatitis (AIP). Other common sites of involvement are the hepatobiliary tract, salivary gland, orbit, and lymph node, however practically any organ can be involved, including upper aerodigestive tract, lung, aorta, mediastinum, retroperitoneum, soft tissue, skin, central nervous system, breast, kidney, and prostate. Fever or constitutional symptoms usually do not comprise part of the clinical picture. Laboratory findings detected include raised serum globulin, IgG and IgG4. An association with autoantibody detection (such as antinuclear antibodies and rheumatoid factor) is seen in some cases. Steroid therapy comprises the mainstay of treatment. Disease progression with involvement of multiple organ-sites may be encountered in a subset of cases and may follow a relapsing-remitting course. The principal histopathologic findings in several extranodal sites include lymphoplasmacytic infiltration, lymphoid follicle formation, sclerosis and obliterative phlebitis, along with atrophy and destruction of tissues. Immunohistochemical staining shows increased IgG4+ cells in the involved tissues (>50 per high-power field, with IgG4/IgG ratio >40%). IgG4-RSD may potentially be rarely associated with the development of lymphoma and carcinoma. However, the nature and pathogenesis of IgG4-RSD are yet to be fully elucidated and provide immense scope for further studies.

Spindle Cell Sarcomas

Information is presented on the pathology of spindle cell sarcomas. Synovial sarcoma, malignant peripheral nerve sheath tumor, fibrosarcoma, inflammatory myofibroblastic tumor, low-grade myofibrosarcoma, leiomyosarcoma, spindle cell rhabdomyosarcoma, and endothelial neoplasms are discussed in terms of an overview of the tumor, microscopic and gross features, diagnostic techniques, genetic markers, differential diagnosis, clinical details, and prognosis.

Fibroinflammatory pseudotumor of the temporal bone

Chronic inflammatory tumor-like lesions of the temporal bone represent a difficult clinical task for the skull base surgeon. Their osteolytic aggressiveness endangers vital structures and may not be controlled by surgery alone. We present the course of four cases of fibroinflammatory pseudotumor of the temporal bone which were treated by a combined approach of skull base surgery and chemotherapy. Three patients were deafened by the disease and underwent several operafive measures. One patient was lost, most likely due to an arrosive bleeding of the internal carotid artery. The chronic and recurrent process could only be stopped by petrosectomy, followed by antiproliferative chemotherapy. Two patients were subsequently provided with a cochlear implant. The differential diagnosis, diagnostic, and operative options of this rare but severe disease are discussed.

Inflammatory pseudotumor of the tonsil

Inflammatory pseudotumor is an unusual benign but potentially invasive lesion. In the head and neck area, it mainly involves the orbit and paranasal sinuses. We present a case in tonsil and neck. After tonsillectomy and steroid therapy, there has been no recurrence.

Inflammatory pseudotumor of the lymph nodes in the neck

Inflammatory pseudotumor is a tumor-like lesion with histopathologic characteristics of inflammation. A 63-year-old woman, who presented with complaints of 2 neck masses on the right side of the neck with waxing and waning course in whom excisional biopsy was performed revealing inflammatory pseudotumor of the lymph node in the neck, is presented, and this rare clinical entity is discussed together with relevant literature.

Imaging of nasopharyngeal inflammatory pseudotumours: differential from nasopharyngeal carcinoma

The purpose of this study was to describe the MRI findings of inflammatory pseudotumours (IPTs) involving the nasopharynx and to differentiate IPTs from nasopharyngeal carcinoma (NPC). The medical records and imaging studies of 7 patients (6 men, 1 woman; age range, 32-71 years; mean age, 52.4+/-18 years) with IPT involving the nasopharynx were reviewed retrospectively. The MRI findings were compared with those of seven patients with advanced NPC with skull base invasion. All patients with IPT involving the nasopharynx presented with single or multiple cranial neuropathies; six reported pain; and four patients had a recent history of otitis media. Three were initially misdiagnosed as having NPC according to MRI findings, and all underwent nasopharyngeal biopsy to exclude malignancy. 7/7 (100%) patients received systemic corticosteroid treatment; 7/7 (100%) showed initial rapid resolution of clinical symptoms or radiographical findings; 3/7 (42.9%) had resolution of all signs and symptoms; 3/7 (42.9%) still have limited residual symptoms; and 1/7 (14.3%) suffered recurrence 3 years after remission. The characteristic MR findings of IPT include an infiltrative growth pattern, minimal to mild mass effect, hypointensity on T(2) weighted images, and moderate homogeneous enhancement after contrast administration. Intact nasopharyngeal mucosa, internal carotid artery encasement and narrowing, extensive pachymeningeal thickening and a relative paucity of associated neck lymphadenopathy are additional MR findings that favour the diagnosis of IPT rather than NPC. In conclusion, IPT involving the nasopharynx has characteristic MR findings which, together with clinical and laboratory presentations, are helpful in differentiating IPT from malignant tumours, especially NPC.

Nodal inflammatory pseudotumor caused by luetic infection

Inflammatory pseudotumor of lymph nodes (IPT-LN) represents an unusual cause of lymphadenitis of unknown etiology. Upon the observation of a case of IPT-LN associated with Treponema pallidum (Tp) infection, we analyzed a series of 9 IPT-LN and 9 extranodal IPT (spleen, 4 cases; lung, orbit, gut, skin, and liver) for the presence of Tp, using a polyclonal antibody anti-Tp. At the time of biopsy, none of the patients was suspected for luetic infection, nor specific serologic tests were available. IPT-LN areas extensively involved the nodal parenchyma in 4 cases, whereas they were focal in the remaining 5 cases. Capsular thickening and inflammation (6/9), venulitis (3/9), small granulomas (3/9), and follicular hyperplasia (7/9) were observed in the associated lymphoid parenchyma. Tp were detected in 4/9 cases of LN-IPT and in none of the extranodal IPT. Tp were extremely abundant within the IPT areas and in the perivascular tissues in the surrounding parenchyma, whereas they were scattered within the capsule. In Tp+ cases, marked follicular hyperplasia was the single distinctively associated feature. Double immunostains revealed that Tp were predominantly contained in the cytoplasm of CD11c+ CD163+ macrophages, some of which co-expressed HLA-DR. In addition, scattered S100+ interdigitating dendritic cells also showed intracytoplasmic Tp. This study shows that a significant number of IPT-LN is associated with Tp infection. A spirochetal etiology can be suspected in cases of IPT-LN, independently from the extension of the lesions, especially when pronounced follicular hyperplasia is found. Infection by Tp of macrophages and dendritic cells are in keeping with in vitro data and indicate that immune mediated mechanisms may be involved in the pathogenesis of the lesions.

[Recurrent inflammatory myofibroblastic tumor with renal, retroperitoneal and lymph node involvement]

Inflammatory myofibroblastic tumors are uncommon and benign tumors with unknown aetiology. First reported in the lungs, the inflammatory myofibroblastic tumors have been observed in other locations, especially in the abdomen and the pelvis. We report a 14-year-old adolescent female, who presented sequentially an inflammatory pseudotumor of lymph node, the left kidney and the retroperitoneum. Extrapulmonary inflammatory myofibroblastic tumors are mesenchymal solid tumors. They are frequently circumscribed and confined to a single organ. The recurrence of some inflammatory myofibroblastic tumors and their expression of chromosomal abnormalities found in some types of lymphoma suggest that some of these lesions constitute a true neoplastic process.

Inflammatory myofibroblastic tumours: where are we now?

Inflammatory pseudotumour is a generic term applied to a variety of neoplastic and non-neoplastic entities that share a common histological appearance, namely a cytologically bland spindle cell proliferation with a prominent, usually chronic inflammatory infiltrate. Over the last two decades, inflammatory myofibroblastic tumour (IMT) has emerged from within the broad category of inflammatory pseudotumour, with distinctive clinical, pathological and molecular features. IMT shows a predilection for the visceral soft tissues of children and adolescents and has a tendency for local recurrence, but only a small risk of distant metastasis. Characteristic histological patterns include the fasciitis-like, compact spindle cell and hypocellular fibrous patterns, which are often seen in combination within the same tumour. Chromosomal translocations leading to activation of the ALK tyrosine kinase can be detected in approximately 50% of IMTs, particularly those arising in young patients. This review will examine the clinical, pathological, and molecular genetic features of IMT and discuss an approach to diagnosis and differential diagnosis.

Follicular lymphoma with prominent sclerosis (“sclerosing variant of follicular lymphoma”) exhibiting a mesenteric bulky mass resembling inflammatory pseudotumor. Report of three cases

We present three cases of follicular lymphoma (FL) exhibiting prominent sclerosis (sclerosing variant of follicular lymphoma), resembling inflammatory pseudotumor (IPT) of the lymph node, arising from mesenteric lymph node. Clinically all three cases represented bulky masses of the mesenteric lymph node. Histologically, the lesions were characterized by neoplastic lymphoid follicles separated by stromal collagenization and sclerotic process, with cellular infiltrate extending into the adjacent adipose tissue. The lesions contained variable cellular spindle cell proliferation and inflammatory infiltrate including numerous reactive T cells and histiocytes. Small capillary proliferation with vascular change was also noted. Immunohistochemical study demonstrated the myofibroblastic nature of the spindle cells. Moreover, neoplastic follicles were composed of intermediate to medium-sized lymphocytes, somewhat resembling reactive lymphoid aggregates. The overall histomorphological findings of the three lesions were similar to those of IPT of the lymph node. However, CD10, Bcl-2 and Bcl-6 immunostaining demonstrated the neoplastic nature of the lymphoid follicles and the lesions were diagnosed as FL grade 1. The present three cases indicate that the sclerosing variant of grade 1 FL should be added to the differential diagnosis from IPT of the lymph node.

Inflammatory Pseudotumor of Pelvic Lymph Nodes

BACKGROUND

Inflammatory pseudotumor is a rare benign cause of lymphadenopathy previously reported in several anatomic locations that can simulate malignant neoplasm.

CASE

A postmenopausal woman presented with abdominal pain, generalized malaise, leukocytosis, and intermittent fevers up to 102 degrees F. A 5-day course of antibiotics was given with persistence of symptoms. Computed tomography of the abdomen and pelvis demonstrated an ill-defined, retroperitoneal soft-tissue density, and lymphadenopathy. She underwent an exploratory laparotomy, total abdominal hysterectomy, bilateral salpingo-oophorectomy, and unilateral pelvic and paraaortic lymphadenotomy. Histologic examination revealed inflammatory pseudotumor of the lymph nodes, with immunohistochemical studies demonstrating actin-positive myofibroblastic cells. Four months after surgery, the patient remains asymptomatic without evidence of disease.

CONCLUSION

Inflammatory pseudotumor of the pelvic lymph nodes is a rare entity and should be included in the differential diagnosis of patients with persistent fever and lymphadenopathy.

CT and MRI appearances of inflammatory pseudotumour of the cervical lymph nodes

Inflammatory pseudotumour (IPT), also known as plasma cell granuloma and inflammatory myofibroblastic tumour, is a rare cause of benign cervical lymphadenopathy which mimics malignant causes of cervical lymphadenopathy. The imaging features of IPT affecting the cervical lymph nodes have not previously been described. We present cross sectional imaging in a case of IPT occurring in a 42-year-old African-Caribbean man, from his initial presentation to a subsequent spontaneous reduction in the extent of lymphadenopathy.

[Inflammatory pseudotumor of lymph node]

INTRODUCTION

Inflammatory pseudotumor of lymph node is a rare case in the etiology of fever of unknown origin.

OBSERVATION

We report the observation of a woman, aged 40, hospitalized with intermittent fever revealing under-diaphragm adenopathy related to inflammatory pseudotumor of lymph node.

CONCLUSION

Inflammatory pseudotumor of lymph node is a rare pathology whose nosological definition is unclear. It should probably be considered as belonging to a category different from the inflammatory pseudotumor of other organs. The diagnosis presents itself in case of isolated adenopathy or prolonged fever and is based on an anatomopathology that essentially calls to mind a lymphoma. The evolution of the condition is shown to be favorable : it can lead to a spontaneous remission, or call for a non-steroid anti-inflammatory treatment, or a steroid therapy.

Inflammatory pseudotumor of the spleen with EBV positivity: report of a case

Inflammatory pseudotumor (IPT) of the spleen is a rare benign tumor with unknown etiology. It causes problems in the diagnosis because of mimicking some hematopoetic malignancies. Here we report the case of a 36-yr-old woman complaining of nausea and insomnia. Laboratory investigations were limited to increase of leukocyte and thrombocyte count. Ultrasonography and magnetic resonance (MR) imaging showed circumscribed solid lobulated mass, measuring about 6.5 cm in diameter, located in the dorsal region of the spleen. Splenectomy was performed with the differential diagnosis including hamartoma and lymphoma of the spleen. Histological examination of the sharply demarcated splenic mass consisted of myofibroblasts and admixture of inflammatory cells. Immunohistochemistry and in situ hybridization were performed. IPT of the spleen was diagnosed. Epstein-Barr virus (EBV) was detected in the tumor by in situ hybridization. This rare entity is presented because of its clinical, radiological and pathological difficulties in the differential diagnosis.

Follicular dendritic reticulum cell tumor mimicking inflammatory pseudotumor of the spleen

In the course of a routine clinical check up of the 54 year old male a splenic well circumscribed tumor like mass of 12 cm in diameter was discovered. Splenectomy with removal of splenic hilar lymph nodes and liver wedge biopsy were performed. Four years later the patient is symptom free. In the removed spleen the tumor like lesion showed a pattern consistent with the diagnosis of inflammatory pseudotumor. However, besides lymphocytes, plasma cells, macrophages, eosinophils and myofibroblasts a high number of slightly polymorphic, frequently binucleated cells positive for CD21 and CD23 were seen. These cells which were scattered or formed smaller or larger groups and fascicles were considered to represent follicular dendritic reticulum cells (FDRCs) and the lesion a FDRC tumor. Flow cytometric DNA ploidy analysis showed a hyperdiploid cell population inside the tumor like lesion. Besides FDRC tumors of high and of intermediate malignancy the present case may represent a low grade type of moderate proliferation activity. The FDRCs of the lesion and a few smaller spindle cells were EBER positive indicative of the presence of EBV. No EBER positive cells were seen in the uninvolved spleen.

Clinical and histological coexistence of inflammatory pseudotumour of the lymph nodes and rheumatoid arthritis

Inflammatory pseudotumour (IPT) of the lymph nodes is an uncommon, self-limiting, non-neoplastic proliferation of spindle cells, associated with a polymorphous inflammatory cell infiltrate embedded in a collagen-rich stroma and a variable degree of fibrosis, arising in the nodal parenchyma. Its clinical picture is characterised by site-specific signs and the presence, in most cases, of constitutional symptoms. The pathogenesis of IPT is unknown, but it has been interpreted as an aberrant reactive condition of the nodal connective framework, possibly related to viral infections or chronic inflammatory conditions. Its prognosis is usually favourable. We here report the simultaneous onset of seronegative rheumatoid arthritis (RA) and nodal IPT in a 31-year-old woman. Notably, in the nodal biopsy the coexistence of rheumatoid nodules, as well as histological and immunohistochemical features of IPT, was observed. To our knowledge, such an association has not been previously reported and the hypothesis that IPT could represent an unusual epiphenomenon of an RA-related chronic inflammatory response is suggested.

Inflammatory myofibroblastic tumors (inflammatory pseudotumors) of the gastrointestinal tract: how closely are they related to inflammatory fibroid polyps?

Inflammatory myofibroblastic tumors (inflammatory pseudotumors) and inflammatory fibroid polyps of the gastrointestinal tract both feature prominent inflammatory infiltrates admixed with spindle-shaped fibroblasts/myofibroblasts set in a collagenous, fibrovascular, or myxoid stroma. Erroneously, some have considered inflammatory fibroid polyps to be intraluminal manifestations of inflammatory myofibroblastic tumors. In this study, we have characterized the histopathology of inflammatory myofibroblastic tumors, tumors that have only rarely been reported in the gastrointestinal tract, and have focused on whether inflammatory myofibroblastic tumors and inflammatory fibroid polyps in the gastrointestinal tract are distinct or similar. Clinical, histopathologic, and immunohistochemical features of 38 inflammatory myofibroblastic tumors limited to the wall of the gastrointestinal tract were compared with those of 45 inflammatory fibroid polyps. Compared to patients with inflammatory fibroid polyps, those with inflammatory myofibroblastic tumors were younger (mean age 41 years vs. 53 years); had larger tumors (mean 8 +/- 5.2 cm vs. 3.6 +/- 4.6 cm); presented with abdominal pain, fever, and weight loss more frequently and less frequently had bowel obstruction. Inflammatory fibroid polyps had more eosinophils and fibrosis and fewer lymphoid cell infiltrates than inflammatory myofibroblastic tumors. A regular vascular pattern was a feature of inflammatory fibroid polyps but not of inflammatory myofibroblastic tumors. Most (82%) inflammatory fibroid polyps were positive for CD34 versus none of the inflammatory myofibroblastic tumors. Smooth muscle actin was more frequently positive in inflammatory myofibroblastic tumors than in inflammatory fibroid polyps (86% versus 13%). Inflammatory myofibroblastic tumors were much less frequent and were more evenly distributed in the gastrointestinal tract than inflammatory fibroid polyps. Both appear to be benign processes. Inflammatory myofibroblastic tumors, but not inflammatory fibroid polyps, had a tendency to recur. In conclusion, inflammatory myofibroblastic tumors of the gastrointestinal tract are extremely rare and differ clinically, histologically, and immunohistochemically from inflammatory fibroid polyps.

Inflammatory myofibroblastic tumour (inflammatory pseudotumour) of the breast. Clinicopathological and genetic analysis of a case with evidence for clonality

Inflammatory myofibroblastic tumours (IMTs) were initially considered to be benign reactive processes, but cases with an unfavourable outcome have been reported. Moreover, clonal genetic alterations have recently been published in some cases, suggesting that IMT may represent a malignant neoplastic entity. This paper reports a case of IMT that developed in the mammary gland, an unusual site. The histological picture was characterized by a proliferation of spindle cells with little cellular atypia and rare mitoses, associated with a polymorphous inflammatory infiltrate. Their immunophenotype, characterized by the expression of vimentin, smooth muscle actin, and cytokeratins, corresponded to that of myofibroblasts. Cytogenetic analysis revealed the clonal nature of the lesion. The modal karyotype was 48, X, ins(2;X)(q34;p21.2p22.2), +7, del(9)(p23), +19. Including the present observation, a 9p deletion has now been found in three cases of IMT. These observations show that IMT may be a clonal neoplasm, even in sites different from deep soft tissues.

Inflammatory pseudotumor of lymph node and spleen: an entity biologically distinct from inflammatory myofibroblastic tumor

Inflammatory pseudotumors (IPTs) of the lymph node and spleen are an uncommon, benign cause of lymphadenopathy and/or splenomegaly that often bear striking clinicopathologic similarities to the inflammatory myofibroblastic tumors (IMTs) found in soft tissues. These tumors have classically been grouped together under the umbrella category of "inflammatory pseudotumor." Recent evidence shows that IMTs are in fact neoplastic processes that often harbor balanced chromosomal translocations involving the ALK kinase gene. These translocations result in expression of ALK kinase in IMTs as assessed by immunohistochemical studies. However, the relationship between IMT and IPT of the lymph node and spleen is uncertain. To determine if ALK tyrosine kinase expression is also present in IPT, 13 cases of IPT (9 involving lymph nodes, 4 splenic lesions) were examined for the presence of ALK tyrosine kinase by immunohistochemical staining on paraffin-embedded tissue. In addition, in situ hybridization studies for Epstein-Barr virus--encoded RNAs (EBER) and immunoperoxidase studies for human herpesvirus-8 (HHV8)--specific proteins were performed. All cases had clinical, morphologic, and immunophenotypic findings typical of IPT and had varying proportions of fibroblastic and inflammatory components. Age ranged from 11 to 75 (median, 40) years; 8 subjects were male, and 5 were female. None of the cases (0 of 13) had positive staining for ALK kinase or HHV8, and in 1 a lymph node (1 of 13) was focally positive for EBV (EBER) by in situ hybridization. The absence of ALK kinase as detected by immunohistochemical studies in IPT of the lymph node and spleen suggests that this entity is biologically distinct from the histologically similar IMT.

Inflammatory pseudotumor of lymph nodes: clinicopathologic and immunohistological study of 11 Japanese cases

We report 11 Japanese cases of inflammatory pseudotumor (IPT) of the lymph node. There were 7 males and 4 females with ages ranging from 5 to 68 years (median; 48). Only 2 patients had systemic lymphadenopathy, and all others had involvement of only 1 lymph node group. Constitutional symptoms such as fever were present in 8 patients and laboratory abnormalities were detected in 5. All patients recovered and were alive and well after 2 to 180 months (median; 32 months). Histologically, the process mainly involved the connective tissue framework of the lymph node, secondarily spreading into the lymph node parenchyma and the perinodal tissue. It was characterized by a storiform growth pattern of myofibroblasts, marked vascularity with associated vascular lesions, and a polymorphous reactive cellular infiltrate in a collagen-rich stroma. An immunohistochemical study revealed numerous myofibroblasts, histiocytes, and vascular endothelial cells expressing vascular endothelial growth factor (VEGF) in 6 cases. It was suggested that VEGF may be involved, in part, in the induction of the angiogenesis of IPT. Moreover, the present study indicates that follicular dendritic cell sarcoma, nasal T/natural killer cell lymphoma, and anaplastic large cell lymphoma should be added to the differential diagnosis from IPT of the lymph node. Int J Surg Pathol 9(3):207-214, 2001

Inflammatory myofibroblastic tumor in children: diagnosis and treatment

BACKGROUND/PURPOSE

Inflammatory myofibroblastic tumor (IMT) is a rare benign neoplasm. Although it is commonly seen in children, the number of childhood cases in the current literature is limited. Furthermore, malignant degeneration or transformation to lymphoma in the recurrent or residual IMT have directed attention to this interesting entity. Herein, the authors present their experience with IMT with special emphasis on diagnosis and treatment.

METHODS

All records of children treated with diagnosis of IMT between 1977 and 1999 inclusive were evaluated retrospectively.

RESULTS

Seven children were treated for IMT with the mean age of 9.14 +/- 2 years (range, 6 to 12 years). Male to female ratio was 5:2. Respiratory symptoms and clubbing were present in a patient with pulmonary IMT (n = 1). Abdominal pain (n = 3), fever (n = 2), and weight loss (n = 4) were encountered in intraabdominal IMTs. The most frequent physical finding was palpable intraabdominal mass (n = 4). Plain films showed nonspecific findings such as radiodense area in the hemithorax (n = 1), displacement of bowel segments (n = 2), air-fluid levels (n = 1), and amorphous calcification (n = 4). Ultrasonography and CT showed calcified masses in 4 cases. Except the case with intrathoracic IMT, all the tumors were located in the abdomen at various sites such as cardioesophageal junction (n = 1), left hepatic lobe (n = 1), mesentery of the small bowel (n = 2), and antimesenteric wall of the descending colon (n = 1), gastrosplenic region and porta hepatis (n = 1). Tumor sizes ranged from 3 x 2 x 2 cm to 15 x 15 x 13 cm. The masses were excised totally in all but one case. Infiltrated organs (esophagogastric junction, a segment of jejunum, and spleen, stomach wall, and renal capsule) were resected in 3 cases. Total surgical excision of IMT was considered adequate for treatment in 6 cases. One patient with aggressive IMT required further treatments such as immunomodulation and chemotherapy and died of neutropenic sepsis.

CONCLUSIONS

IMT is a benign neoplasm rarely presented with malignant features such as local invasiveness, recurrence, distant metastasis, or malignant transformation. IMT can be suspected preoperatively through some hematologic abnormalities and radiologic findings, but precise diagnosis should be made on the basis of histologic findings. Complete surgical resection and close follow-up are all necessary for appropriate treatment to avoid recurrences as well as unnecessary and potentially harmful therapy. The optimal management of locally aggressive and recurrent forms should be decided individually for each patient. J Pediatr Surg 36:908-912.

Inflammatory myofibroblastic tumor of the skin

We report a case of inflammatory myofibroblastic tumor (IMF) of the skin in a female with a history of Wegeners granulomatosis. The patient had a painless, erythematous, and indurated lesion of the left elbow. The resected specimen revealed a 4 cm x 3 cm nodule involving the entire dermis and superficial portions of subcutis with a stellate profile at scanning magnification. There were spindle cells in fascicles and whorls and a mixed inflammatory cell infiltrate of plasma cells, lymphocytes, neutrophils, and eosinophils. The spindle cells were immunoreactive for vimentin, muscle specific actin, and smooth muscle actin. The polyclonal and polymorphous nature of the inflammatory cells was confirmed by immunohistochemical studies. This is the first case of IMF of the skin documented by immunostaining.

Development of a calcifying fibrous pseudotumour within a lesion of Castleman disease, hyaline-vascular subtype

A nine year old boy with localised Castleman disease of the hyaline-vascular subtype developed a calcifying fibrous pseudotumour. This pathological association does not appear to have been described before. In this case, the development of this very unusual soft tissue tumour-like process was thought to be related to a previous fine needle aspiration biopsy, which was performed because of lymphadenopathy localised to the right inguinal area. This case provides further evidence of the reactive nature of calcifying fibrous pseudotumour and also broadens the pathological spectrum of the stromal cell proliferation that occasionally supervenes within lesions of Castleman disease, hyaline-vascular type.

Inflammatory pseudotumor in the mandibular retromolar region

An unusual pseudosarcomatous lesion of the oral mucosa is described in a 43-year-old woman. It presented as an aggressive ulcerative mass in the mandibular retromolar gingiva of one month's duration. The lesion was composed of florid myofibroblastic and fibrohistiocytic proliferations with infiltrative margins in an inflammatory background and was considered to be an inflammatory pseudotumor. Although the tumor appeared to have been incompletely excised, the patient remains free of disease at 1 year follow-up.