Inflammatory pseudotumour of soft tissues: a clinicopathological and immunohistochemical analysis of 18 cases

Inflammatory myofibroblastic tumor of the thyroid gland

Inflammatory myofibroblastic tumor (IMT) is a mesenchymal tumor with low incidence, which is extremely rare in the thyroid. At present, there is a lack of understanding regarding the etiology, pathogenesis, diagnosis and treatment of thyroid IMT. To improve the understanding of the disease, this article reviews the pathogenesis, clinical manifestations, pathology and immunohistochemistry, diagnosis, therapy and prognosis of thyroid IMT.

Inflammatory myofibroblastic tumor of the spleen: a case report

Inflammatory myofibroblastic tumors (IMTs), otherwise known as the inflammatory pseudotumor, is a rare solid mesenchymal tumor, simulating malignant neoplasms, histologically characterized by the proliferation of spindle cells in a fibrous myxoid stroma containing inflammatory cells. CT and MR imaging are the most used tools in their assessment. Clinical features are nonspecific and depend on the localization of the tumor, radiologic findings are polymorphic and no-conclusive and present a diagnostic challenge to the radiologist. Although histology remains obligatory for the final diagnosis. Heren, we report a case of splenic IMT with histological correlation.

Inflammatory myofibroblastic tumor arising from soft tissues of extremities harboring a novel CLIP2-ALK fusion

A 34-year-old Chinese woman found a lump in her left leg for more than 3 weeks without any discomfort. Grossly, the tumor was relatively well delineated with focal infiltration. Histopathologic evaluation showed a compact fascicular spindle cell proliferation with variable myxoid and collagenous stroma and scattered inflammatory infiltrate. Immunohistochemically, the tumor cells showed positive expression of ALKD5F3 and SMA and negative expression of CD34, desmin, and cytokeretin. Fluorescence in situ hybridization analysis of the ALK locus showed break-apart signals in 20% of tumor cells, and DNA sequencing discovered a novel CLIP2-ALK fusion gene. The lesion was diagnosed as an inflammatory myofibroblastic tumor (IMT). To the best of our knowledge, this is the first case with CLIP2-ALK gene fusion in the somatic soft tissue IMTs.

The Activity of Chemotherapy in Inflammatory Myofibroblastic Tumors: A Multicenter, European Retrospective Case Series Analysis

BACKGROUND

This study aimed to review the activity of cytotoxic chemotherapy in patients with inflammatory myofibroblastic tumors (IMTs) treated at nine European sarcoma reference centers.

MATERIALS AND METHODS

Patients of any age, with histologically proven IMT, treated with anthracycline-based methotrexate plus/minus vinorelbine/vinblastine (MTX-V) or other chemotherapeutic regimens between 1996 and 2018 were retrospectively reviewed. Diagnosis was confirmed at the local level by an expert pathologist. Response was retrospectively assessed by local investigators by RECIST v1.1. Progression-free survival (PFS), relapse-free survival (RFS), and overall survival (OS) were computed by Kaplan-Meier method.

RESULTS

Thirty-eight patients were included. Twenty-five patients (8 localized, 17 advanced disease) received an anthracycline-based regimen; 21 were evaluable for response. Overall response rate (ORR) was 10/21 (47.6%). At a 70.8-month median follow-up (FU), median RFS and median OS were not reached (NR) in patients with localized disease; median PFS and median OS were 6.3 (interquartile range [IQR]: 1.9-13.4) and 21.2 (IQR: 7.7-40.7) months in patients with advanced disease. Thirteen patients received MTX-V (4 localized, 9 advanced disease), all evaluable for response. ORR was 7/13 (53.8%). At a 56.6-month median FU, median RFS and median OS were 42.5 (IQR: 12.9-61.2) months and NR (no death events) in patients with localized disease, and NR (IQR: 24.9 to NR) and 83.4 months (IQR: 83.4 to NR) in patients with advanced disease. In the "other-regimens group," responses were seen in 3/4 patients treated with oral cyclophosphamide and 1/2 with docetaxel/gemcitabine.

CONCLUSION

Anthracycline-based and MTX-V regimens are very effective in IMT, with a similar ORR in both groups. MTX-V achieved a prolonged disease control. Responses were also seen with oral cyclophosphamide and docetaxel/gemcitabine, but few patients were treated with these schedules.

IMPLICATIONS FOR PRACTICE

Inflammatory myofibroblastic tumor (IMT) is an ultrarare sarcoma with known sensitivity to anaplastic lymphoma kinase (ALK) inhibitors in ALK-fused cases, although ALK inhibitors are not licensed in the disease. The current knowledge on the activity of cytotoxic chemotherapy is limited. This multi-institutional retrospective study on pediatric and adult patients with IMT shows that cytotoxic chemotherapy, and in particular anthracycline-based and methotrexate plus/minus vinorelbine/vinblastine regimens, represents a treatment option and can be considered in IMT patients irrespectively from ALK status. This study provides a benchmark for future studies on new medical therapies.

Mesenchymal Neoplasms of the Genitourinary System: A Selected Review with Recent Advances in Clinical, Diagnostic, and Molecular Findings

Mesenchymal neoplasms of the genitourinary (GU) tract often pose considerable diagnostic challenges due to their wide morphologic spectrum, relative rarity, and unexpected incidence at GU sites. Soft tissue tumors arise throughout the GU tract, whether from adventitia surrounding or connective tissues within the kidneys, urinary bladder, and male and female genital organs. This selected article focuses on a subset of these lesions, ranging from benign to malignant and encompassing a range of patterns of mesenchymal differentiation, where recent scholarship has lent greater insight into their clinical, molecular, or diagnostic features.

Inflammatory myofibroblastic tumors of the pancreas in children: A case report and literature review

INTRODUCTION

Inflammatory myofibroblastic tumors are an uncommon neoplasm, which are very rarely located in the pancreas. Clinically and radiologically, this rare pancreatic tumor presents as an abdominal mass lesion that mimics other pancreatic tumors, and should therefore be considered in the differential diagnosis of pancreatic tumors.

CLINICAL FINDINGS AND DIAGNOSIS

The 15-year-old boy complained of abdominal pain over the left upper quadrant with intermittent fever for 7 days. Abdominal sonography revealed one cystic lesion with a hyperechoic component in the left upper quadrant of the abdomen. Surgical excision was performed and postoperative findings indicated a pancreatic tail tumor. The pathology indicated inflammatory myofibroblastic tumors. To our knowledge, this patient is a unique case as the tumor was located in the pancreatic tail only, sparing the body.

INTERVENTIONS AND OUTCOMES

The patient underwent tumor resection and segmental resection of the transverse colon with simple closure. The patient had no evidence of disease recurrence at 3 years follow-up.

CONCLUSION

Inflammatory myofibroblastic tumors of the pancreas in children are extremely rare. Surgical excision is the standard treatment, and corticosteroids use in children need more large-scale studies.

Inflammatory myofibroblastic tumour

While initially controversial, the proposal that a subset of inflammatory pseudotumours were myofibroblastic neoplasms is now acknowledged. Inflammatory myofibroblastic tumour is a spindle cell neoplasm of intermediate biological potential that may arise in a wide range of anatomic sites but has a particular propensity for the lung and abdominal soft tissues. Depending on its location, IMT may present with a variety of clinical symptoms and it may also express a variable pathologic phenotype, leading to a broad range of clinical and pathological differentials. Recent discoveries about the molecular signatures of IMT not only provide additional tools to assist in their diagnosis, they also point to possible therapeutic interventions that may transform the management algorithms for patients with this condition.

Mesenchymal tumours of the mediastinum--part I

The mediastinum is an anatomically defined space in which organs and major blood vessels reside with surrounding soft tissue elements. The thymus is an important organ in the mediastinum, and many of the masses encountered in the mediastinum are related to this organ. Most neoplasms diagnosed in the mediastinum are epithelial tumours (thymomas and thymic carcinomas), lymphomas or germ cell tumours. In contrast, soft tissue tumours of the mediastinum are rare. In 1963, Pachter and Lattes systematically reviewed soft tissue pathology of the mediastinum, covering the hitherto described [2, 226, 227] In this review, based on the 2013 WHO classification of soft tissue tumours and the 2015 WHO classification of tumours of the lung, pleura, thymus and heart, we provide an updated overview of mesenchymal tumours that may be encountered in the mediastinum.

Neoadjuvant Crizotinib in Advanced Inflammatory Myofibroblastic Tumour with ALK Gene Rearrangement

Background

Inflammatory myofibroblastic tumours (IMTs) are rare sarcomas that were first described in the lung. They are composed of myofibroblastic mesenchymal spindle cells accompanied by an inflammatory infiltrate of plasma cells. Complete resection is the treatment of choice. There is currently no standard treatment for inoperable or recurrent disease. Expression of ALK protein triggered by ALK gene rearrangement at chromosome 2p23 has been found in 36%-60% of IMTs.

Case report

We report a rapid early response to crizotinib as neoadjuvant therapy, enabling surgical excision of a large ALK(-translocated IMT, which resulted in complete disease clearance. To the best of our knowledge, this is the first case in the literature of a patient with IMT in whom crizotinib was used successfully in the neoadjuvant or curative setting.

Maxillary sinus inflammatory myofibroblastic tumors: a review and case report

An inflammatory myofibroblastic tumor (IMT) is an immunohistochemically diverse entity demonstrating neoplastic and nonneoplastic qualities. Although IMTs can arise in any area of the body, lesions arising in certain sites, namely, the nasal cavity, paranasal sinuses, and pterygopalatine fossa, demonstrate a heightened neoplastic and invasive potential. Despite case specific complete tumor regression and disease remission in response to pharmacotherapeutics, a subset of IMTs remain resistant to all forms of therapy. We present such a case, a 34-year-old female patient, with a highly resistant, maxillary sinus IMT. Her refractory, ALK-1 negative IMT has not responded well to novel therapies reported in current literature. This case suggests the role of zonal expressivity within a single lesion as a probable mechanism for its highly resistant nature and should promote determination of each IMT's cytogenetic profile to provide more effective targeted therapy. Paper includes a literature review of all maxillary sinus IMTs from 1985 to 2014 along with their immunohistochemical staining, treatments, and outcomes.

A rare tumor of trachea: Inflammatory myofibroblastic tumor diagnosis and endoscopic treatment

Inflammatory myofibroblastic tumors (IMTs) are rare childhood neoplasms, with benign clinical course. Although etiology of IMTs are not clear, recent studies have reported that IMT is a true neoplasm rather than a reactive or inflammatory lesion. IMTs are rarely seen in adults and tracheal involvement is also rare both in adults and also in children. We describe a 16-year old female patient who was misdiagnosed and treated as asthma in another center for a few months and presented with acute respiratory distress due to upper airway obstruction. Computerized tomography (CT) of the chest and rigid bronchoscopy revealed a mass lesion that was nearly totally obliterating tracheal lumen. Bronchoscopic resection was performed under general anesthesia and the final pathological diagnosis was tracheal IMT.

Inflammatory myofibroblastic tumor: a rare tumor in the tongue

Inflammatory myofibroblastic tumor is composed of myofibroblast and inflammatory cell infiltration of the tissue. Malign transformation and recurrence rate of this tumor is rare and accepted as benign fibroinflammatory disease. The main etiology is unclear, but infection, trauma, and immunologic event are accused. In this study, we presented a 75-year-old man with a mass on his tongue, which was diagnosed as “inflammatory myofibroblastic tumor.” This type of tumor is rarely seen in the tongue and might be difficult to diagnose. Complete mass excision was provided for an adaquete treatment.

Rare gastric inflammatory myofibroblastic tumor in an adult woman: a case report with review of the literature

Inflammatory myofibroblastic tumor (IMT) of the stomach is extremely rare and its prognosis is unpredictable. We present a 37-year-old woman with a gastric IMT. She presented epigastric pain since 2 months, anemia and weight loss associated. Physical examination showed cutaneous pallor and mild abdominal tenderness in the epigastrium. Abdominal ultrasonography showed a tumor near the pancreas and the CT scan revealed that the lesion was arising from the stomach. Upper endoscopy showed a submucosal lesion of approximately 7.5 cm located in the posterior wall of the gastric body such as a gastrointestinal stromal tumor (GIST). The patient underwent a subtotal gastrectomy and Billroth I reconstruction. The histopathological and immunohistochemical analysis revealed an IMT that originated from the gastric wall.

Head and neck inflammatory myofibroblastic tumor (IMT): evaluation of clinicopathologic and prognostic features

Owing to rarity and awareness deficiency towards inflammatory myofibroblastic tumor (IMT), we sought to review on its clinicopathological features; arising awareness to achieve early diagnosis; exploring prognostic factors and then establishing a treatment protocol. Retrospective study was performed on patients with histological proven IMT between January 2003 and December 2010. Their demographic data, clinical and histological presentations were recorded. Overall survival (OS) and progression-free-survival (PFS) were estimated via Kaplan-Meier method. Cox regression model was applied to determine the significant of prognostic factors. Logistic regression model was established to predict the probability of relapse. A total of 28 patients. Five-year PFS was 65%. Surgical margins primarily and independently determined the survival, followed by size, pseudocapsule of the lesion, intra-lesional necrosis and lastly Ki-67 and ALK overexpression. Logistic model in prediction of relapse was established, with the formula as probability of relapse = 1/(1 + e(-z)) where e = exponential function, z = constant value (3.9) + B*margin + B*size + B*immunohistochemical expression + B*pseudocapsule + B*intra-lesional necrosis. Immunohistochemical overexpression was significant if Ki-67 was strongly expressed with a conditioned ALK overexpression simultaneously. Staining intensity must be at least moderate for those ALK nuclear staining was less than 25%. Weak ALK staining intensity is only significant if nuclear staining was more than 25%. Diagnosis of IMT is achieved via exclusion. Radical resection and obtaining negative margins remains the mainstay of treatment. Both high and moderate-risk groups required post-operative radiotherapy. In low-risk group, post-operative radiotherapy was recommended if the lesion is larger than 5 cm in diameter with a conditioned ALK & Ki-67 overexpression.

Postaural inflammatory pseudotumor: an extremely unusual complication of trauma in a child

We report the case of a 12-year-old boy who presented with a rapidly enlarging, painless mass behind the ear following trauma to the area. The mass was excised, and histopathologic and immunohistochemical evaluations revealed it to be an inflammatory pseudotumor. At 1 year postoperatively, the child exhibited no evidence of recurrence.

The immunohistochemical profile of oral inflammatory myofibroblastic tumors

OBJECTIVE

The aim of this study was to demonstrate the immunohistochemical profile of oral inflammatory myofibroblastic tumors (IMTs) along with morphologic analysis.

STUDY DESIGN

Three cases diagnosed as oral IMTs were selected to compile an immunohistochemical panel constituted by calponin, caldesmon, Bcl-2, desmin, fibronectin, CD68, Ki-67, S100, anaplastic lymphoma kinase (ALK), α-smooth muscle actin, cytokeratins AE1/AE3, muscle-specific actin, CD34, and vimentin. An oral squamous cell carcinoma with a focal area of desmoplastic stroma was used as control for the stained myofibroblastic cells.

RESULTS

All oral IMTs were positive for calponin, revealing a strong and diffuse expression in the spindle-shaped cells. The lesions were also positive for vimentin (3/3), fibronectin (3/3), α-smooth muscle actin (3/3), and muscle-specific actin (1/3) and negative for h-caldesmon, Bcl-2, desmin, CD68, Ki-67, S100, ALK, cytokeratins AE1/AE3, and CD34.

CONCLUSIONS

Within the results encountered, the present panel should be of great assistance in the diagnosis of oral IMTs.

Oral inflammatory myofibroblastic tumor: case report and review of literature

Inflammatory myofibroblastic tumor (IMT) is a rarely described tumor of unknown etiology and pathogenesis. It occurs primarily in the lungs, but has occurred in other extra-pulmonary sites. Histologically these lesions appear as an inflammatory infiltrate within a variably myofibrotic background. Current evidence shows that inflammatory myofibroblastic tumors are neoplastic processes resulting from chromosomal translocations that often cause an overexpression of ALK kinase, which is often assessed using immunohistochemical studies. Currently, the biological behavior of oral inflammatory myofibroblastic tumor is still uncertain. This article describes the clinical, histological, and operative features of a case of IMT of the oral cavity.

IgG4 plasma cells in inflammatory myofibroblastic tumor: inflammatory marker or pathogenic link?

Inflammatory myofibroblastic tumor is a rare mesenchymal neoplasm that harbors an anaplastic lymphoma kinase (ALK) gene rearrangement in the majority of cases. It is composed of fibroblastic-myofibroblastic cells with a characteristic inflammatory infiltrate that consists predominantly of plasma cells. In contrast, IgG4-related sclerosing disease is a recently described multisystem disorder with a histological appearance similar to inflammatory myofibroblastic tumor. The plasma cell infiltrate is characteristic in IgG4-related sclerosing disease and has been studied as a tool to render this diagnosis. Histologically, the two disorders overlap, although there are significant clinical differences. This study analyzes the histological appearance of 36 inflammatory myofibroblastic tumors, compares them with IgG4-related sclerosing disease, and assesses the plasma cell profile using immunohistochemistry to determine the range and proportion of IgG4 plasma cells. The majority of patients were children and young adults, mainly with solitary masses and no clinical manifestations of IgG4-related sclerosing disease. ALK-1 positivity was present in 23 cases (64%). None showed obliterative phlebitis or prominent lymphoid aggregates. Of 36 inflammatory myofibroblastic tumors, 15 cases showed an IgG4/IgG ratio ≥0.10, a cutoff described in the literature as supportive of IgG4-related sclerosing disease and up to 33 IgG4-positive plasma cells per high-power field indicating a mild-to-moderate increase as compared with IgG4-related sclerosing disease. Currently, the diagnostic recognition of inflammatory myofibroblastic tumor is based on clinicopathological features and diagnostic adjuncts, such as ALK-1 reactivity and genetic tests. Although inflammatory myofibroblastic tumor and IgG4-related sclerosing disease are distinct entities, a subset of inflammatory myofibroblastic tumors exhibit an IgG4/IgG ratio that is within the range for IgG4-related sclerosing disease. Therefore, the ratio alone cannot be used as a reliable discriminator between these two entities and other clinical and pathologic features must always be taken into account.

Post-traumatic inflammatory pseudotumor of the breast with atypical morphological features: A potential diagnostic pitfall. Report of a case and a critical review of the literature

Although inflammatory pseudotumor (IPT) and inflammatory myofibroblastic tumor (IMT) may share a common morphology, they are distinct clinico-pathologic entities. Unfortunately, the terms IMT and IPT are still used interchangeably, especially when lesions occur in unusual sites, including breast. All the cases of IMT/IPT involving the breast have raised spontaneously without any apparent prior injury. We herein report the first case of a post-traumatic IPT of the breast parenchyma in a 22-year-old male. Histologically, the lesion was highly cellular and composed of spindle cells arranged in a predominant fascicular pattern. Notably, mono- or multi-nucleated large pleomorphic cells were observed. Inflammatory cells, especially plasma cells and lymphocytes, were closely admixed with the spindle cell proliferation. The overall picture was reminiscent of an "IMT with atypical features", typically seen in lung, abdomen, pelvis, and retroperitoneum of children. Immunohistochemically, the spindle-shaped and large pleomorphic cells were immunoreactive to vimentin, α-smooth muscle actin, and desmin. No immunoreactivity was obtained with ALK-1 protein. The present case contributes to widening the morphological spectrum of IPT of the breast, emphasizing the possibility that a reactive lesion may contain large pleomorphic cells that may represent a potential diagnostic pitfall. Lastly, we suggest that the diagnosis of IMT of the breast should be rendered with caution when dealing with ALK-negative spindle cell lesions in adult patients, and alternative diagnoses, including IPT, should be seriously considered.

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.

Unusual case of pancreatic inflammatory myofibroblastic tumor associated with spontaneous splenic rupture

Background

Spontaneous splenic rupture considered a relatively rare but life threatening. The three commonest causes of spontaneous splenic rupture are malignant hematological diseases, viral infections and local inflammatory and neoplastic disorders. We describe a unique and unusual case of inflammatory myofibroblastic tumor of the tail of pancreas presented with massively enlarged spleen and spontaneous splenic rupture.

Case presentation

A 19 years old male patient with no significant past medical history presented to emergency room with abdominal pain and fatigue. Massively enlarged spleen was detected. Hypotension and rapid reduction of hemoglobin level necessitated urgent laparatomy. About 1.75 liters of blood were found in abdominal cavity. A large tumor arising from the tail of pancreas and local rupture of an enlarged spleen adjacent to the tumor were detected. Distal pancreatectomy and splenectomy were performed. To our knowledge, we report the first case of massively enlarged spleen that was complicated with spontaneous splenic rupture as a result of splenic congestion due to mechanical obstruction caused by an inflammatory myofibroblastic tumor of the tail of pancreas. A review of the literature is also presented.

Conclusion

Inflammatory myofibroblastic tumor of the tail of pancreas should be included in the differential diagnosis of the etiological causes of massively enlarged spleen and spontaneous splenic rupture.

Inflammatory pseudotumor: report of a case in the mandible

BACKGROUND

Intraoral inflammatory pseudotumor (IPT) is a rare, benign non-neoplastic lesion that presents as a rapidly growing mass with aggressive behavior, which can be mistaken for a malignant process.

CASE REPORT

This article presents a rare case of IPT of the mandible in a 70-year-old male patient. Examination of the oral cavity revealed a hemorrhagic soft mass of the mandibular region. The patient was treated with surgery. Histologic examination of the resected specimen showed proliferation of fascicular spindle cells and a dense, chronic inflammatory cell infiltrate consisting of neutrophils, eosinophils, and lymphocytes. Immunohistochemically, the spindle cells expressed vimentin, α smooth muscle actin, and CD68, indicating a diagnosis of IPT.

DISCUSSION

IPT is an unusual benign pathology in the oral and maxillofacial area. Because of its aggressive clinical and radiological features, it can be mistaken for a malignancy. We suggest that oral and maxillofacial surgeons should be aware of the specific features of IPT to avoid unnecessary aggressive treatments such as a radical resection.

An inflammatory myofibroblastic tumor of the ampulla of vater successfully managed with endoscopic papillectomy: report of a case

Inflammatory myofibroblastic tumors (IMTs) are solid neoplastic mesenchymal proliferations composed of myofibroblastic spindle cells admixed with inflammatory infiltrates. The documented sites in the gastrointestinal tract include the esophagus, small intestine, colon, appendix, rectum, pancreas, spleen, liver, and Meckel's diverticulum. Biliary IMTs are rare, and IMTs arising from the ampulla of Vater have not been reported previously. Herein we report the case of a 65-year-old woman with an extrahepatic biliary obstruction due to IMT of the ampulla of Vater, and a successful therapeutic approach using endoscopic ultrasonography and endoscopic papillectomy.

Plexiform angiomyxoid myofibroblastic tumor of the stomach

Plexiform angiomyxoid myofibroblastic tumor of the stomach is a unique mesenchymal tumor that we first described in 2007. The tumor is very rare, and to date, only 18 cases confirmed by immunohistochemistry have been reported in the literature. The patients’ ages ranged from 7 to 75 years (mean, 43 years), and the male-to-female ratio was approximately 1:1. Representative clinical symptoms are ulceration, associated upper gastrointestinal bleeding (hematemesis), and anemia. The tumors are located at the antrum in all cases, and grossly, the tumor is whitish to brownish or reddish, and forms a lobulated submucosal or transmural mass. Microscopically, the tumor is characterized by a plexiform growth pattern, the proliferation of cytologically bland spindle cells, and a myxoid stroma that is rich in small vessels and positive for Alcian blue stain. Immunohistochemically, the tumor cells are positive for α-smooth muscle actin and negative for KIT and CD34. Differential diagnoses include gastrointestinal stromal tumor and other mesenchymal tumors of the gastrointestinal tract. Some authors proposed that this tumor should be designated as “plexiform fibromyxoma”, but this designation might cause confusion. The tumor is probably benign and thus far, neither recurrence nor metastasis has been reported.

Huge pelvi-abdominal malignant inflammatory myofibroblastic tumor with rapid recurrence in a 14-year-old boy

Inflammatory myofibroblastic tumor (IMT) is an uncommon benign neoplasm with locally aggressive behavior but malignant change is rare. We report an unusual case of pelvic-abdominal inflammatory myofibroblastic tumor with malignant transformation in a 14-year-old boy presenting with abdominal pain and 9 kg body weight loss in one month. Computed tomography revealed a huge pelvi-abdominal mass (30 cm), possibly originating from the pelvic extraperitoneal space, protruding into the abdomen leading to upward displacement of the bowel loops, downward displacement of the urinary bladder, massive central necrosis, a well-enhanced peripheral solid component with prominent peritumoral vascularity. Subsequent examination confirmed the computed tomographic findings. Histopathologic examination revealed proliferative epitheloid and spindle cells, inflammatory cell infiltration and high mitotic counts. Immunohistochemistry was strongly positive for anaplastic lymphoma kinase and revealed a high proliferative index (ki-67 = 40%). DNA sequencing and electronic microscopy further confirmed the primitive fibroblastic cell phenotype of the tumor and a final diagnosis of inflammatory myofibroblastic tumor with malignant transformation was established. Rapid tumor recurrence was noted 20 d after radical tumor resection. To our knowledge, this is the largest documented case of IMT in a pediatric patient and the first report of IMT with malignant transformation originating from the pelvic extraperitoneal space.

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.

Primary gastric inflammatory myofibroblastic tumor: a clinicopathologic and immunohistochemical study of 5 cases

Primary gastric inflammatory myofibroblastic tumors are rare. Here we report on 5 such cases (4 males and 1 female, age range 36-45 years). Their presenting symptoms included abdominal mass (5 patients), abdominal pain (4 patients), and upper gastrointestinal hemorrhage (1 patient). Tumor size ranged from 4.5 to 8 cm in the greatest dimension. Histologically, these tumors showed three patterns: myxoid hypocellular, fascicular, and hyalinized. A lymphoplasmacytic infiltrate was present in all 5 tumors. One to two mitotic figures were recognized in 10 high power fields (HPFs) in 4 patients and focally up to 5 in 10HPFs in 1 patient. No prominent nuclear atypia or necrosis was observed. ALK, smooth muscle actin, and vimentin staining were observed in all tumors. One tumor focally expressed desmin. S-100, CD21, CD34, CD35, CD68, and CD117 were negative in all IMTs. The patients were followed up for 2-5 years (mean 3.4 years), and none of them had tumor metastasis or died. Only one patient developed local recurrence and is now alive with no evidence of disease after the second surgery (11 months after the second surgery). Our results indicate that primary gastric IMTs have an intermediate behavior as seen at other sites.

A case of cutaneous inflammatory myofibroblastic tumor

Pseudo-inflammatory tumors are also known as plasma cell granuloma, inflammatory pseudo-tumor and inflammatory myofibroblastic tumor, and these tumors are a group of highly variable proliferations of myofibroblastic cells that are associated with a prominent inflammatory infiltrate. This tumor is known to most commonly occur in the lungs, bladder and gastrointestinal system with only a few cases having been reported in the skin. A previously healthy 26-year-old man presented with a 6-year history of an intermittently pruritic lesion on his back. On the histologic examination, there were spindle cells in fascicles and a mixed inflammatory cellular infiltrate of plasma cells and lymphocytes. A diagnosis of inflammatory fibroblastic tumor was made and the nodule was surgically removed. We report here on an additional case of this rare cutaneous entity, and it is probably the first such report from Korea.

Marginal zone B-cell lymphoma arising from buccal mucosa resembling inflammatory myofibroblastic tumor of the soft tissue

We report here a case of marginal zone B-cell lymphoma (MZBL) arising from buccal mucosa resembling inflammatory myofibroblastic tumor (IMT) of the soft tissue. On a low-power field, the lesion is characterized by fibrous granulation tissue and numerous lymphoid follicles with or without atrophic small germinal center. A portion of the lymphoid follicles were surrounded by partial and/or complete thin pale cuff of centrocyte-like (CCL) cells on high power field. The thin rim of the lymphoid follicles contained CCL-cells, plasma cells, cells showing plasma cell differentiation and mature eosinophils. In contrast, the granulomatous areas contained were characterized by haphazardly arranged spindle cells, mature plasma cells, mature eosinophils, small-to-medium lymphocytes and histiocytes. Histologically, IMT was suspected. However, flow cytometry and immunohistochemical study demonstrated a monotypic nature of centrocyte-like cells, plasma cells and their precursor and confirmed the diagnosis of MZBL arising from the buccal mucosa. The differential diagnostic problems between IMT of the soft tissue and classical Hodgkin lymphoma and T-cell lymphoma have been discussed previously. However, the present case indicated that MZBL should be added to the differential diagnosis of IMT of the soft tissue.

Application of immunohistochemistry to soft tissue neoplasms

CONTEXT

Soft tissue tumors are composed of numerous and complex diagnostic entities. Because of this complexity and the recognition of an intermediate malignancy category including some tumors with a deceptively bland histologic appearance, soft tissue tumors may represent a major diagnostic challenge to the general practicing pathologist.

OBJECTIVE

To correctly diagnose soft tissue tumors with the ancillary use of immunohistochemistry.

DATA SOURCES

Review of the current literature with emphasis on those tumors for which immunohistochemistry has proven to be particularly useful.

CONCLUSIONS

Immunohistochemistry plays an important role in the diagnosis of soft tissue tumors. One of its major utilities is to correctly identify a tumor as being of mesenchymal or nonmesenchymal origin. Once mesenchymal origin has been established, histologic subtyping according to specific cell lineage may be achieved with the use of lineage-specific markers. Tumors of uncertain cell lineage and tumors with primitive small round cell morphology are often characterized by a unique immunohistochemical phenotype. In this group of tumors, immunohistochemistry is most widely applied and is of greatest value. Despite the rapid development of molecular genetic techniques, immunohistochemistry still remains the most important diagnostic tool in the diagnosis of soft tissue tumors aside from recognition of morphologic features and clinical correlation.

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.

Inflammatory myofibroblastic tumor of the trachea

Inflammatory myofibroblastic tumor of the trachea is a rare benign tumor in children. We describe a 9-year-old girl who presented with recurrent episodes of wheeze and severe respiratory distress requiring mechanical ventilation. She had recurrent collapses of the right lung and a chest CT and bronchoscopy confirmed the presence of an obstructing mass lesion at the carina. The lesion, 1.5 cm x 1.5 cm in size, was debulked by rigid bronchoscopy and histopathology revealed features of inflammatory myofibroblastic tumor. A repeat bronchoscopy at 1 month of follow up did not reveal any residual lesion.

Gastrointestinal stromal tumors: diagnostic challenges and practical approach to differential diagnosis

Over the last decade, gastrointestinal stromal tumors (GISTs) have evolved from histogenetically obscure gastrointestinal mesenchymal tumors to well-defined tumors with distinctive clinical, morphologic, ultrastructural, histogenetic, and molecular characteristics, for which targeted therapy is available. This is largely attributable to the discovery of CD117 overexpression and activating mutations in c-kit or platelet-derived growth factor alpha genes in most of GISTs. The availability of specific diagnostic tests and targeted therapy for GISTs has led to an increased awareness of these tumors. At the same time, the list of potential GIST mimics has lengthened considerably and it has become increasingly important that GISTs be distinguished from their mimics because correct diagnosis has implications for both treatment and prognosis. The purpose of this review is to provide an update of the expanding differential diagnosis of GISTS, to draw attention to unusual GIST variants, to provide a practical approach the differential diagnosis of GISTs and to highlight some of the challenges faced by pathologists in resolving this differential diagnosis.

Inflammatory myofibroblastic tumor: comparison of clinicopathologic, histologic, and immunohistochemical features including ALK expression in atypical and aggressive cases

Inflammatory myofibroblastic tumor (IMT) is a neoplasm of intermediate biologic potential. In this study, we report a subset of IMTs with histologic atypia and/or clinical aggressiveness that were analyzed for clinicopathologic features, outcome, and immunohistochemical expression of anaplastic lymphoma kinase (ALK) and other markers to identify potential pathologic prognostic features. Fifty-nine IMTs with classic morphology (5 cases), atypical histologic features (21 cases), local recurrence (27 cases), and/or metastasis (6 cases) were studied. Immunohistochemistry was performed for ALK1 and other markers (Mib-1, c-Myc, cyclin D1, caspase 3, Bcl-2, Mcl-1, survivin, p27, CD56, p53, MDM-2) using standard techniques. The 59 IMTs had an age at diagnosis ranging from 3 weeks to 74 years (mean 13.2 y, median 11 y, 44% in the first decade). The mean tumor size was 7.8 cm. Sites included the abdomen or pelvis in 64%, lung in 22%, head and neck in 8%, and extremities in 5%. The follow-up ranged from 3 months to 11 years, with a mean of 3.6 years and a median of 3 years. Thirty-three patients had local recurrences, including 13 with multiple local recurrences and 6 patients with both local recurrences and distant metastases. Six patients died of disease, 5 with local recurrences, and 1 with distant metastases. Histologic evolution to a more pleomorphic cellular, spindled, polygonal, or round cell morphologic pattern was observed in 7 cases. Abdominal and pelvic IMTs had a recurrence rate of 85%. Recurrent and metastatic IMTs were larger, with mean diameters of 8.7 and 11 cm, respectively. Cytoplasmic ALK reactivity was seen in 56%. ALK-negative IMTs occurred in older patients (mean age 20.1) years and had greater nuclear pleomorphism, atypia, and atypical mitoses. All 6 metastatic IMTs were ALK-negative. Nuclear expression of p53 was detected in 80% of IMTs overall, but in only 25% of the metastatic subset. There were no significant differences among the subgroups for c-Myc, cyclin D1, MDM-2, Mcl-1, Bcl-2, CD56, p27, caspase 3, or survivin expression. In conclusion, among these 59 IMTs, ALK reactivity was associated with local recurrence, but not distant metastasis, which was confined to ALK-negative lesions. Absent ALK expression was associated with a higher age overall, subtle histologic differences, and death from disease or distant metastases (in a younger subset). Other proliferative, apoptotic, and prognostic markers did not correlate well with morphology or outcome. Thus, ALK reactivity may be a favorable prognostic indicator in IMT and abdominopelvic IMTs recur more frequently.

A rare case of inflammatory pseudotumour of the submandibular lymphnode

Inflammatory pseudotumour (IPT), also known as inflammatory myofibroblastic tumour, is a rare cause of benign cervical lymphadenopathy. In its acute clinical presentation it mimics malignant and infective causes of cervical lymphadenopathy. The combined clinical history, histopathological findings, and imaging features of an infiltrating soft-tissue mass should lead to the possibility of IPT. Radical surgery should be avoided before there is histological proof of a malignant tumor.

Oral inflammatory myofibroblastic tumor demonstrating ALK, p53, MDM2, CDK4, pRb, and Ki-67 immunoreactivity in an elderly patient

Inflammatory myofibroblastic tumor (IMT) is a controversial lesion composed of myofibroblasts, accompanied by varying numbers of inflammatory cells. Various pathogenetic factors have been proposed (ie, reactive, infectious, autoimmune, and neoplastic) but the etiology of most IMTs remains unknown. Here we review the literature of oral IMTs, detailing the demographic profile of these rare lesions. Moreover, we present an unusual case of IMT arising from the mandibular alveolar mucosa of an 82-year-old female. Microscopic examination revealed plump spindle cells set in a myxoid vascular stroma admixed with inflammatory cells. Numerous large ganglion cell-like cells were seen, some exhibiting emperipolesis of neutrophils. Ultrastructurally, prominent myofibroblasts with abundant rough endoplasmic reticulum were noted. Tumor cells were immunoreactive for vimentin, smooth muscle actin, and KP1 (CD68), and negative for desmin, S-100, and EBV-LMP. The lesion was excised without margins and the patient has manifested no evidence of disease at an 18-month recall. In an attempt to further delineate the potential neoplastic nature of this lesion, we assessed the immunohistochemical expression of various markers that have been linked to neoplastic transformation. The recorded positivity for ALK, p53, MDM2, CDK4, pRb, and Ki-67, despite the absence of bcl-2 reactivity, strongly favors the neoplastic origin of the studied tumor.

Inflammatory myofibroblastic tumor of the uterus: a clinicopathologic study of 6 cases emphasizing distinction from aggressive mesenchymal tumors

Inflammatory myofibroblastic tumor (IMT) is an indolent spindle cell proliferation that can histologically resemble various malignant mesenchymal neoplasms; however, it generally behaves as a benign or locally recurrent tumor. Most IMTs involve the lung, mesentery, omentum, or retroperitoneum. We report the clinical and pathologic features of six IMTs of the uterus, one of which was included in a previous report, and emphasize the histologic and immunohistochemical features that distinguish IMTs from uterine spindle cell neoplasms that require aggressive treatment. Recently, translocations of the anaplastic lymphoma kinase (ALK) gene and immunohistochemical expression of ALK have been reported in IMTs of various anatomic sites. We compared ALK expression in uterine IMTs with that in uterine mesenchymal neoplasms with which it may be confused. Patients with IMT were between 6 and 46 years of age. None had a history of abdominal surgery; three were multiparous. The IMTs ranged from 1 to 12 cm in maximum dimension. Three grew as polypoid masses that arose in the lower uterine segment, and two of these prolapsed through the cervical os. The three other tumors grew as bulky myometrial masses with focally irregular borders and infiltrated the endometrium, parametrium, or cervical stroma. There were three main microscopic patterns: a hypocellular pattern, a fascicular pattern, and a hyalinized pattern. A lymphoplasmacytic infiltrate was present in all of the tumors, and most had a myxoid background. Mitotic activity ranged from 0 to 2 mitotic figures per 10 high power fields (HPF) except in one tumor that focally had up to 8 mitotic figures per 10 HPF. No nuclear atypia or necrosis was present. Immunohistochemical expression of ALK was present in a cytoplasmic pattern in all IMTs tested. No ALK expression was identified in uterine leiomyoma (n = 7), leiomyosarcoma (n = 6), carcinosarcoma (n = 4), endometrial stromal sarcoma (n = 4), or normal uterine tissues. Follow-up ranging from 1.5 years to 5 years in 4 patients with uterine IMTs revealed no recurrence or metastasis. IMTs should be differentiated from aggressive uterine mesenchymal tumors because they can be treated conservatively and have a more favorable prognosis. ALK expression appears to be of diagnostic value in conjunction with other immunohistochemical stains.

So-called inflammatory myofibroblastic tumour: a proliferative lesion of fibroblastic reticulum cells?

The term inflammatory pseudotumour was originally used in a generic fashion for any lesion which simulated a neoplastic condition at a clinical, macroscopic and microscopic level but which was thought to have an inflammatory/reactive pathogenesis. In more recent times, the term has been employed in a more restrictive sense for a mass lesion characterized microscopically by the proliferation of a spindle cell component against a heavy inflammatory infiltrate of mixed composition but usually with a predominance of mature lymphocyte and plasma cells. The spindle cell component has generally been regarded as being of mesenchymal nature and having morphological and phenotypical features consistent with fibroblasts or myofibroblasts, the latter cell being clearly preferred over the former in the more resent reports. The term inflammatory myofibroblastic tumour (IMFT) is the one currently favoured, which proposes the myofibroblastic nature of the process. It is the purpose of this review to bring forth some evidence that the neoplastic spindle cell component of IMFT may be instead derived from the subtype of cells of the accessory immune system that have been variously called fibroblastic reticulum cells, myoid cells, and dictyocytes.