p53 Mutation and MDM2 amplification in inflammatory myofibroblastic tumours

A diagnostically challenging case of inflammatory myofibroblastic tumor primary to the peritoneum

Introduction

Inflammatory myofibroblastic tumors are difficult to diagnose because of the lack of specific indicators. We describe a diagnostically challenging case of an inflammatory myofibroblastic tumor primary to the peritoneum.

Case presentation

The patient was a 25-year-old male who presented at our hospital with lower abdominal pain. Computed tomography revealed a mass lesion 80 mm in diameter just above the bladder. This was suspected to be a bleeding tumor of the urachus. Since malignancy could not be ruled out, surgery was planned. This revealed a fragile tumor arising from the peritoneum. Following its removal, the tumor was diagnosed by histopathological analysis as an inflammatory myofibroblastic tumor.

Conclusion

We describe a case of inflammatory myofibroblastic tumor primary to the peritoneum diagnosed by histopathology. Inflammatory myofibroblastic tumor should be considered in the differential diagnosis of abdominal wall and anterior bladder tumors.

Gastric and cardiac inflammatory myofibroblastic tumor: an extremely rare case

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a unique, rarely metastatic tumor composed of myofibroblasts and fibrous spindle cells with inflammatory cell infiltration that can affect any organ in the human body. By reviewing the relevant literature on PubMed, we found that this is the first case report of IMT with both gastric and cardiac involvement.

CASE PRESENTATION

A 57-year-old male patient was admitted to the hospital with complaints of malaise, poor appetite, and epigastric pain with black stools. We found a mass in the patient's stomach and left atrium by contrast-enhanced computed tomography, 18 F-fluorodeoxyglucose positron emission tomography/computed tomography, and other tests. The patient underwent laparoscopic Billroth II subtotal gastrectomy and Braun's gastrointestinal reconstruction under general anesthesia. On the 46th day following stomach surgery, the cardiac tumor was removed under general anesthesia. The patient has treated with doxorubicin 70 mg of D1 chemotherapy two months after cardiac surgery. Postoperative pathological immunohistochemistry of the mass confirmed the diagnosis of an IMT. His review three months after the cardiac surgery suggested the progression of the left atrial mass, but he declined further treatment and finally died one month after the review.

CONCLUSIONS

As a unique class of tumors that rarely metastasize, IMTs have an unknown etiology and pathogenesis, and distant metastasis is primarily observed in patients with negative activin receptor-like kinase (ALK) expression. The preferred treatment for IMT is complete surgical resection, and the effectiveness of adjuvant therapy for patients with distant metastases is still being determined. The clinical presentation of IMT lacks specificity and is often related to the location of tumor growth, which poses a diagnostic challenge. Pathological immunohistochemistry is the only way to confirm the diagnosis at present. Our case report reminds clinicians that a category of ALK-negative IMT with a tendency toward distant metastasis should not be ignored.

Update of Diagnosis and Targeted Therapy for ALK+ Inflammation Myofibroblastic Tumor

OPINION STATEMENT: Inflammatory myofibroblastic tumor (IMT), characterized by intermediate malignancy and a propensity for recurrence, has presented a formidable clinical challenge in diagnosis and treatment. Its pathological characteristics may resemble other neoplasms or reactive lesions, and the treatment was limited, taking chemotherapies as the only option for those inoperable. However, discovering anaplastic lymphoma kinase (ALK) protein expression in approximately 50% of IMT cases has shed light on a new diagnostic approach and application of targeted therapies. With the previous success of combating ALK+ non-small-cell lung cancers with ALK tyrosine kinase inhibitors (TKIs), crizotinib, a first-generation ALK-TKI, was officially approved by the U.S. Food and Drug Administration in 2020, to treat unresectable ALK+ IMT. After the approval of crizotinib, other ALK-TKIs, such as ceritinib, alectinib, brigatinib, and lorlatinib, have proven their efficacy on ALK+ IMT with sporadic case reports. The sequential treatments of targeted therapies in may provide the insight into the choice of ALK-TKIs in different lines of treatment for unresectable ALK+ IMT.

Epithelioid inflammatory myofibroblastic sarcoma: a case report and brief literature review

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a rare variant of the inflammatory myofibroblastic tumor, characterized by more aggressive clinical course and nuclear membrane staining of anaplastic lymphoma kinase (ALK) with ALK rearrangement. An elderly male came to the clinic because of an accidental abdominal mass. Abdominal and pelvic enhanced CT revealed a tumor apparently orginated from mesenchymal tissue. Subsequently, the abdominal mass and multiple organ resection was performed, and the mass was pathologically confirmed as EIMS. The patient developed Clavien-Dindo Grade III postoperative complications and was discharged after his condition improved. He received doxorubicin monotherapy after operation, but only one cycle was administered due to severe vomiting. The follow-up of 5 months after operation showed no evidence of recurrence. Given the rarity of EIMS, and ALk inhibitors have a long and robust effect on patients with ALK gene tumors, it is very important for clinicians to be familiar with the clinicopathological features of EIMS, which will contribute to the accurate diagnosis of EIMS and reduce misdiagnosis.

Inflammatory myofibroblastic tumor of the distal common bile duct: Literature review with focus on pathological examination

Inflammatory myofibroblastic tumor (IMT) of the biliary tract is rare, and often difficult to diagnose or to distinguish from other tumors due to its atypical clinical presentation and nonspecific radiological features. Histologically, IMTs are (myo)fibroblastic neoplasms with a prominent inflammatory infiltrate. They are characterized by receptor tyrosine kinase gene rearrangements, most often involving an anaplastic lymphoma kinase (ALK) translocation. The final diagnosis of IMT depends on histopathology and immunohistochemical examination. In this manuscript, we provide a clinical and morphomolecular overview of IMT and the difficulties that may arise in using immunohistochemical and molecular techniques in diagnosing IMT.

Primary inflammatory myofibroblastic tumour of the liver: a clinicopathological and genetic study including a subset with ETV6::NTRK3 fusion

AIMS

Inflammatory myofibroblastic tumour (IMT) is an intermediate neoplasm and rarely occurs in the liver. The aim of this study was to analyse the clinicopathological and genetic features of the largest primary hepatic IMT.

METHODS AND RESULTS

A total of 10 cases were identified (four males and six females aged 1-48 years, median = 35 years) from 2011 to 2021, which accounted for 2.5% of IMTs occurring in all organ systems. Histological findings revealed that myofibroblastic/fibroblastic cells with inflammatory infiltration and focal hypocellularity were observed in three children. Immunostaining showed ALK-diffuse cytoplasmic positive in six cases (six of 10; 60%) and pan-TRK nuclear positive in three cases (three of 10; 30%). Hypercellular pattern was detected in ALK-positive IMTs and obvious collagenous/myxoid matrix was observed in the pan-TRK-positive subgroup. ALK rearrangement was demonstrated in three of five interpretable ALK-positive IMTs by fluorescence in-situ hybridisation (FISH), and one case failed due to poor sample quality. Next-generation sequencing indicated an IMT with TFG::ALK and FCHSD2::ALK fusion and TP53 mutation. ETV6::NTRK3 fusion was confirmed by RT-PCR, but FISH-negative results were found in two of three cases with pan-TRK-positive IMTs. No genetic alteration was detected in one tumour. One patient died 1 year after biopsy, while nine patients survived without evidence of disease in the follow-up surveillance (17-119 months).

CONCLUSIONS

This article describes the first example of primary paediatric hepatic IMTs with ETV6::NTRK3 fusion. Besides the common ALK-positive subgroup, the proportion of NTRK3 fusion is high. Recognising the association between clinicopathological and molecular alterations is critical to accurate diagnosis of hepatic IMTs.

Case report: Epithelioid inflammatory myofibroblastic sarcoma treated with an ALK TKI ensartinib

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is an aggressive variant of inflammatory myofibroblastic tumor (IMT) and has a poor prognosis. EIMS is characterized by epithelioid morphology, neutrophilic infiltrate and specific fusion partners of anaplastic lymphoma kinase (ALK). Despite no standard therapy for EIMS, ALK tyrosine kinase inhibitors (TKIs) are recommended for these tumors. The present case describes an abdominal mass that presented in a 31-year-old male. The patient suffered from recurrence and multiple metastases 2 months after surgery. Ensartinib was administered and RANBP2-ALK fusion was detected. A partial response has been observed for 4 months and there has been no recurrence. This study provided a successful case with sustained response of targeted therapy.

Primary intrathoracic liposarcomas: A clinicopathologic and molecular study of 43 cases in one of the largest medical centers of China

Introduction

Primary intrathoracic liposarcoma is extremely rare, and most published series lack genetic analyses. The aim of our study is to better understand the clinicopathologic and genetic features of these rare lesions.

Materials and methods

Forty-three primary intrathoracic liposarcomas were identified and most cases were analyzed by systematic genetic studies, including fluorescence in situ hybridization (FISH), whole-exome sequencing (WES), and Sanger sequencing.

Results

This series included 27 males and 16 females (ratios, 1.68:1) aged 24-73 years (median, 53 years). Tumors mainly occurred in the mediastinum (n=23, 53.5%), followed by pleural cavity (n=16, 37.2%) and lung (n=4, 9.3%). The study included 21 well-differentiated liposarcomas (WDLs), 19 dedifferentiated liposarcomas (DDLs), 2 myxoid pleomorphic liposarcomas (MPLs) and 1 pleomorphic liposarcoma (PL), without identification of myxoid liposarcoma. FISH analysis identified MDM2 amplification in 17 of 18 WDLs (94.4%) and all DDLs (16/16, 100.0%). The MDM2-nonamplified WDL was CDK4-nonamplified but FRS2-amplified. WES and Sanger sequencing found somatic TP53 mutation in the 2 MPLs. Follow-up information was available for 33 of 38 cases (86.8%). Thirteen patients (39.4%) showed no evidence of disease, 10 patients (30.3%) were alive with disease, and 8 patients (24.2%) died of disease. Fourteen cases developed recurrence and 1 with metastasis.

Conclusions

WDL/DDL was the overwhelming subtype in this location, followed by MPL and PL. Analysis of the FRS2 gene, in combination with MDM2 and other genes of 12q13-15, may more precisely characterize WDL/DDLs. MPL is the most fatal subtype of this site. Further studies are needed to explore the role of TP53 in the pathogenesis of MPL.

Inflammatory Myofibroblastic Tumour: State of the Art

Simple Summary

Among sarcomas, which are rare cancers, inflammatory myofibroblastic tumors are extremely rare. Unlike other subtypes, this is a largely oncogene-driven neoplasia, and early gene rearrangement identification is important for accurate advanced stage treatment. In this manuscript, we review the clinicopathologic characteristics of this ultra-rare entity, as well as the current treatment landscape, with a particular focus on opportunities provided by tyrosine kinase inhibitors (TKIs).

Abstract

An inflammatory myofibroblastic tumor (IMT) is a neoplasm composed of myofibroblastic and fibroblastic spindle cells accompanied by inflammatory cells, including lymphocytes and eosinophils. It is an ultra-rare tumor, the optimal management of which remains to be defined. Surgery is the treatment of choice for localized tumors. The treatment of advanced disease is not precisely defined. Chemotherapy regimens result in an overall response rate of approximately 50% based on retrospective data. The latest pathophysiological data highlight the role played by tyrosine kinase fusion genes in IMT proliferation. Anaplast lymphoma kinase (ALK) oncogenic activation mechanisms have been characterized in approximately 80% of IMTs. In this context, data regarding targeted therapies are most important. The aims of this article are to review the latest published data on the use of systematic therapy, particularly the use of molecular targeted therapy, and to publish an additional case of an IMT with Ran-binding protein 2 (RANPB2)-ALK fusion showing a long response to a tyrosine kinase inhibitor.

[Histological, immunohistochemical and molecular study of a paratesticular dedifferentiated liposarcoma with inflammatory myofibroblastic tumor-like features]

We report the histological, immunohistochemical, and molecular findings of a dedifferentiated liposarcoma with inflammatory myofibroblastic tumor-like features occurring in the paratesticular region. Histologically, the dedifferentiated component closely resembled an inflammatory myofibroblastic tumor. The neoplastic cells were positive for smooth muscle actin with focal CD56, CD99, Bcl2 and EMA expression. WT1, calretinin, myogenin, CK(AE1/AE3), desmin, H-caldesmon, CD34, ALK, CKIT, DOG1, MUC4 and STAT6 were negative. MDM2 showed diffuse and strong nuclear positivity in neoplastic cells and fluorescence in situ hybridization (FISH) revealed amplified MDM2 (high level) but no SYT rearrangement. Although a lipomatous component was evident macroscopically, well-differentiated liposarcomatous components were not evident in the section examined. Dedifferentiated liposarcoma can have prominent inflammatory myofibroblastic tumor-like features. Pathologists should be aware of this histological variant in order to avoid misdiagnosing dedifferentiated liposarcoma as inflammatory myofibroblastic tumor or other spindle cell tumors which have different behavioral patterns and treatment requirements.

What do we know about inflammatory myofibroblastic tumors? - A systematic review

BACKGROUND

Inflammatory myofibroblastic tumors (IMTs) are rare intermediate-grade neoplasms that have a high recurrence rate after excision and exhibit low metastatic potential. These tumors contain proliferating neoplastic, fibroblastic and myofibroblastic cells, and are also characterized by chronic inflammatory infiltration by lymphocytes, plasma cells, eosinophils, and histiocytes. They belong to the group of inflammatory spindle cell lesions. Some reactive lesions, such as inflammatory pseudotumors, may appear to be IMTs, which makes their differential diagnosis extremely difficult. The aim of this article is to compile the recent information on IMTs to aid in their diagnosis and treatment.

METHODS

We reviewed articles published between 2017 and 2021, which were selected from online medical databases. In addition, some earlier articles and latest scientific monographies were analyzed.

RESULTS

The terminology used for inflammatory spindle cell lesions seems to be confusing. The terms "inflammatory myofibroblastic tumors" and "inflammatory pseudotumors" are interchangeably used by many scientists. However, a detailed analysis of the development of terminology suggests that the term "inflammatory myofibroblastic tumors" should be used to refer to a neoplastic lesion.

CONCLUSIONS

IMTs are rare neoplasms, which have not been investigated in detail due to the difficulty in collecting a large number of cases. Thus, our knowledge about this disease remains unsatisfactory. Recently developed techniques such as next-generation sequencing and computer-aided histopathological diagnosis may be useful in understanding the etiopathology of IMTs, which will help in the selection of the most appropriate therapy for patients.

Comprehensive Molecular Analysis of Inflammatory Myofibroblastic Tumors Reveals Diverse Genomic Landscape and Potential Predictive Markers for Response to Crizotinib

PURPOSE

The European Organization for Research and Treatment of Cancer (EORTC) clinical phase II trial 90101 "CREATE" showed high antitumor activity of crizotinib, an inhibitor of anaplastic lymphoma kinase (ALK)/ROS1, in patients with advanced inflammatory myofibroblastic tumor (IMFT). However, recent findings suggested that other molecular targets in addition to ALK/ROS1 might also contribute to the sensitivity of this kinase inhibitor. We therefore performed an in-depth molecular characterization of archival IMFT tissue, collected from patients enrolled in this trial, with the aim to identify other molecular alterations that could play a role in the response to crizotinib.

EXPERIMENTAL DESIGN

Twenty-four archival IMFT samples were used for histopathological assessment and DNA/RNA evaluation to identify gene fusions, copy-number alterations (CNA), and mutations in the tumor tissue. Results were correlated with clinical parameters to assess a potential association between molecular findings and clinical outcomes.

RESULTS

We found 12 ALK fusions with 11 different partners in ALK-positive IMFT cases by Archer analysis whereas we did not identify any ROS1-rearranged tumor. One ALK-negative patient responding to crizotinib was found to have an ETV6-NTRK fusion in the tumor specimen. The CNA profile and mutational landscape of IMFT revealed extensive molecular heterogeneity. Loss of chromosome 19 (25% of cases) and PIK3CA mutations (9% of cases) were associated with shorter progression-free survival in patients receiving crizotinib.

CONCLUSIONS

We identified multiple genetic alterations in archival IMFT material and provide further insight into the molecular profile of this ultra-rare, heterogeneous malignancy, which may potentially translate into novel treatment approaches for this orphan disease.

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 Myofibroblastoma of the Breast: A Case Report

Inflammatory myofibroblastic tumor (IMT) is a rare tumor with low-grade malignant risk mainly occurring in soft tissues and lungs, and it is extremely rare in the breast. Meanwhile, imaging findings of the tumor often present with non-specific features that lead to misdiagnosis and delayed treatment. Here, we report a case of inflammatory myofibroblastic tumor in the breast with the imaging findings of mammography, magnetic resonance imaging (MRI), and pathologic findings to improve the understanding of the disease. The patient was treated by surgical operation, and was followed up for 44 months, no local recurrence and distant metastasis.

Colonic inflammatory myofibroblastic tumour presenting as 'pyrexia of unknown origin': report of a rare disease and its unique presentation

An intra-abdominal inflammatory myofibroblastic tumour (IMT) belongs to a rare group of diseases initially described as an inflammatory pseudotumour. Even though it is seen more often in children, its incidence in adults is even rarer. Clinical presentations can vary depending on its site and inherent tumour properties. The colon is an uncommon site for IMT and pyrexia of unknown origin (PUO) as its dominant clinical presentation is even rarer. A 27-year-old woman presented with PUO. She was evaluated under the department of internal medicine before undergoing an 18F-fluorodeoxyglucose positron emission tomography-computed tomography scan. This showed an intensely enhancing descending colon mass. An image-guided biopsy of this lesion was reported as IMT. She underwent a left hemicolectomy and complete excision of the tumour, following which her symptoms resolved completely. The patient has been disease-free at a 6-month follow-up and is asymptomatic at 1 year.

Echocardiographic Findings in Children with Native Mitral Valve Masses Complicated by Systemic Embolization

• Case of mitral valve IMT with embolization. • Case of Streptococcus pneumoniae mitral valve endocarditis with embolization. • Use of 2D and 3D echocardiography for management of mitral valve masses.

A Pancreatic Inflammatory Myofibroblastic Tumor with Spontaneous Remission: A Case Report with a Literature Review

The inflammatory myofibroblastic tumor (IMT) is a rare tumor that can develop in any systemic organ. Its features are generally benign, but it often resembles malignancies and is treated surgically. Our patient was an 82-year-old female complaining of abdominal discomfort. Computed tomography demonstrated a 5 cm, ill-enhanced mass at the pancreas head. Upper gastrointestinal endoscopy revealed a duodenal submucosal tumor with apical erosion. Endoscopic ultrasonography (EUS) demonstrated a heterogeneous, low-echoic pancreas mass without clear margins. Fine-needle aspiration biopsy (FNAB) demonstrated spindle myofibroblastic tissues with lymphoplasmacyte and eosinophil infiltration, confirming an IMT diagnosis. Surprisingly, the tumor spontaneously regressed in one month without medication. Histological diagnosis using EUS-FNAB is essential for the rare pancreatic solid tumor like IMT.

Cytohistological and immunohistochemical characteristics of spindle-shaped mesenchymal neoplasms occurring in the gastrointestinal tract

The purpose of the present review is to analyze the cytohistological and immunohistochemical characteristics of spindle-shaped mesenchymal gastrointestinal neoplams (MGNs), a group of unusual neoplastic conditions with different biological behavior. These tumors exhibit clinical pictures strictly related to the site of origin and dimensions, even if they appear generally with an intramural localization. This latter point may suggest an useful application of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), mainly followed by the cell-block procedure (CBP) in the differential diagnostic approach. First of all, we discuss the most common entity of MGNs represented by gastrointestinal stromal tumors (GISTs), analyzing the morphologic characteristics and stressing the strength of immunohistochemical algorithm for diagnostic purposes. Successively, we have reported the less common group of spindle-shaped MGNs comprehensive of those arising elsewhere the soft tissues, such as leiomyomas, leiomyosarcomas, schwannomas, inflammatory myofibroblastic tumor and intra-abdominal desmoid fibromatosis. Finally, very uncommon spindle-shaped MGNs, like clear cell, follicular dendritic cell, undifferentiated pleomorphic and radiation-induced sarcomas as well as spindle cell dedifferentiated liposarcomas, have been briefly mentioned.

ALK gene alterations in cancer: biological aspects and therapeutic implications

ALK was first reported in 1994 as a translocation in anaplastic large cell lymphoma and then described with different abnormalities in a number of tumors. Recently, a shortly accumulated biomedical research clarified the numerous biological processes underlying its ability to support cancer development, growth and progression. Advent of precision medicine has finally provided unexpected advances, leading to the development of ALK-targeting inhibitors with superior efficacy as compared with standard chemotherapy regimens, as well as the identification of resistance mechanisms and the creation of ‘next-generation’ treatments. This review summarizes the current understanding of ALK-driven cancers from the oncogenesis and mutation frequency by The Cancer Genome Atlas database through the diagnostic approach, to an updated portrait of available tyrosine kinase inhibitors, considering their effectiveness in cancer treatment, the molecular reasons of therapeutic failure, and the actual and future ways to overcome resistances.

Successful combination chemotherapy for metastatic inflammatory myofibroblastic tumor: A case report

A 64-year-old male presented with increased abdo-minal fullness and fever. Radiological examination revealed moderate ascites, a tumor with a diameter of 12.5 cm in the mesenteric region, as well as multiple tumors in the thoracic and abdominal para-aortic regions and in the left supraclavicular regions. Pathohistological findings of the biopsy specimen revealed atypical spindle cells accompanied by infiltration of lymphocytes. The plasmacytes were positive for CD68, murine double minute 2 and S-100, while they were negative for α-smooth muscle actin, cyclin-dependent kinase 4 and anaplastic lymphoma kinase. Clinically, the patient presented systemic symptoms and laboratory results indicated an elevation in the inflammatory response, while the CT and MRI findings were consistent with an inflammatory myofibroblastic tumor (IMT). Based on the clinical and histological findings, the patient was diagnosed with IMT. In total, 4 cycles of combination chemotherapy with doxorubicin and ifosfamide were administered. Tumor size reduction by 50% was achieved subsequent to the 4th chemotherapy cycle. In conclusion, successful control of this rare metastatic IMT was achieved by systemic chemotherapy.

Retrospective and comparative study of inflammatory myofibroblastic tumor of the liver

BACKGROUND AND AIM

Inflammatory myofibroblastic tumor of the liver (IMTL) is a very rare benign disease with a good prognosis. The study aims to determine the clinical, radiological, and pathological characteristics of IMTL. The diagnosis and treatment strategies were discussed.

METHODS

A total of 11 patients with pathologically confirmed IMTL receiving treatment over a 15-year period were reviewed retrospectively. The analysis included demographics information and pertinent clinical data. Results obtained from patients with hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (IHCC), and metastatic liver cancer (MLC) receiving surgical resection were compared.

RESULTS

In comparison to HCC, IHCC, and MLC, IMTL has an earlier onset (P < 0.001). IMTL patients had significantly lower aspartate aminotransferase (P = 0.003) and higher alkaline phosphatase (P = 0.034) than HCC patients, and higher gamma-glutamyl transpeptidase (P = 0.010) than MLC patients. Increased serum α-fetoprotein level was detected in only one patient. Serum α-fetoprotein was significantly lower in patients with IMTL (P = 0.000) than in those with HCC but not IHCC (P = 0.558) or MLC (P = 0.514). In contrast to elevated serum CA19-9 in patients with HCC/IHCC/MLC, the serum CA19-9 in IMTL cases was generally normal (vs HCC P = 0.008; vs IHCC P = 0.000; vs MLC P = 0.022). In nine IMTL patients, the tumor appeared as a hypoechogenic solid mass on the ultrasonography. In contrast, most patients with HCC, IHCC, or MLC showed hybrid echo. In contrast computed tomography and magnetic resonance imaging, the lesion of IMTL and MLC appeared as peripheral enhancement.

CONCLUSION

Lab tests, imaging features, and patient history are helpful in the differential diagnosis of IMTL from HCC/IHCC/MLC. Surgical resection is curative for IMTL.

Inflammatory myofibroblastic tumor of the urinary bladder in a patient with the left renal cell carcinoma: A case report

This case report describes an inflammatory tumor of the urinary bladder along with left renal cell carcinoma which occurred in a 73-year-old male with a narrowed orificium urethrae internum and severe hyperplasia of the prostate gland. A biopsy was not obtained prior to surgery. An inflammatory myofibroblastic tumor (IMT) of the urinary bladder is a rare benign lesion, particularly in the elderly. To the best of our knowledge, there are no studies concerning IMTs of the urinary bladder in patients with unilateral renal cell carcinoma. A bladder lesion due to an IMT may be easily misdiagnosed as metastasis from left renal cell carcinoma due to the hypervascularity of the tumor. In this case, radical surgery of the cancer of the left kidney was performed by laparoscopy. Subsequently, after three weeks and according to the examination of the intraoperative frozen-sections, a partial cystectomy was performed. Thus, radical resection of the bladder and the associated complications were avoided.

Mesenchymal Tumors of the Gastrointestinal Tract Other than GIST

Mesenchymal tumors involve the gastrointestinal (GI) tract more frequently than other visceral organs. Many such tumors are small, and are benign and increasingly being detected incidentally during colonoscopic screening. Some tumors show distinctive features at this site, such as schwannoma and clear cell sarcoma-like tumor of the GI tract. Without knowledge of these features, recognition of these tumor types can be difficult. This reviews addresses recent developments and diagnostic features of mesenchymal tumors of the GI tract other than gastrointestinal stromal tumor (GIST).

Paratesticular cellular angiofibroma with atypical (bizarre) cells: case report and literature review

We report the extremely unusual occurrence of a cellular angiofibroma (CAF) with atypical (bizarre) cells in the spermatic cord. We present a 63-year-old man, who was referred to the Urology Service with a six-month history of a slowly growing painless nodule in the right inguino-scrotal area. The clinical impression was that of a lipoma. The mass was locally excised. Gross examination showed a well-circumscribed neoplasm attached to the spermatic cord and measuring 5cm in the greatest dimension. Microscopic examination of the tumor showed the appearance of CAF with scattered severely atypical (bizarre) cells distributed throughout the lesion. By immunohistochemistry, atypical cells showed diffuse expression of p16, CDK-4, CD34 and vimentin. Keratin AE1/AE3, S-100 protein, p53, and epithelial membrane antigen were negative. The patient is free of disease two months after tumor excision. To the best of our knowledge, this is the third case of CAF with atypical (bizarre) cells occurring in the paratesticular area. Pathologists should be aware of this morphological variation of CAF to avoid misdiagnosis and over-treatment.

Malignant inflammatory myofibroblastic tumor of the bladder with rapid progression

A 71-year-old man was referred for painless hematuria and a bladder tumor. Cystoscopy and computed tomography revealed a 3-cm oval nodular mass on the left lateral side of the bladder. The patient underwent a complete transurethral resection of the lesion and histology showed a proliferation of atypical spindle cells with inflammation consistent with a myofibroblastic tumor. After 4 and 7 months, follow-up cystoscopy demonstrated nodular mass lesions and transurethral resection of bladder tumor was done, which showed chronic cystitis and a recurred myofibroblastic tumor, respectively. Five months later, multiple lymph node, bone, and soft tissue metastases were found by positron emission tomography. The patient was treated first with palliative chemotherapy, including doxorubicin and cisplatin. After that, radiologic studies showed disease progression but the patient refused further treatment and died 6 months later.

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.

Abdominal inflammatory myofibroblastic tumor a clinicopathologic study with reappraisal of biologic behavior

BACKGROUND AND PURPOSE

Inflammatory myofibroblastic tumor (IMT) is a proliferative lesion of controversial nosology and uncertain prognosis. In an attempt to acquire further understanding of pathogenesis and biologic behavior, we surveyed abdominal IMTs managed over the last 12 years at a single institution.

METHODS

Intra-abdominal IMTs treated between 1995 and 2007 were reviewed concerning demographic, clinical, and pathologic features as well as therapeutic management and outcome. All specimens were reevaluated by histologic examination and immunohistochemistry.

RESULTS

There were 7 patients (4 males; age range, 28 days to 14 years). Five lesions were located in alimentary tract: 1 gastric presenting with bleeding, 1 hepatic presenting with a thoracic wall mass, 1 pancreatic and 2 colonic presenting with obstructive symptoms. One splenic IMT was found incidentally. The remaining case arose from the adrenal gland and presented with a palpable mass. The gastric and adrenal IMTs had evidence of a previous or concomitant infectious setting. Five lesions were excised. The pancreatic IMT underwent a drainage procedure followed by steroid administration, and the hepatic lesion received antibiotics. Histopathology revealed characteristic findings of IMT. Expression of anaplastic lymphoma kinase was negative in all cases. At a median follow-up of 6 years (range, 3-15), all children were asymptomatic with no recurrences. The hepatic and pancreatic IMT displayed complete and near total regression, respectively.

CONCLUSION

A benign behavior of abdominal IMTs was observed even in patients not undergoing surgical excision. Although IMT remains a surgical disease, a conservative approach may be reasonable in select cases.

Comparison of the clinical and immunohistochemical features, including anaplastic lymphoma kinase (ALK) and p53, in inflammatory myofibroblastic tumours

This retrospective study evaluated 15 cases of inflammatory myofibroblastic tumours (IMTs) to determine histological atypicality, clinicopathological features, outcomes, and expression of anaplastic lymphoma kinase-1 (ALK1) and p53, to assess potential pathological prognostic indicators. Nine patients with complete follow-up had no evidence of recurrence, including two with recurrent disease who were treated with additional surgery. Six patients had local recurrence and distant metastasis. Six (40.0%) tumours showed cellular atypicality. Significant correlations were found between histological atypicality and recurrence and metastasis. Recurrence was documented in 25.0% of ALK-positive and 63.6% ALK-negative IMTs, whereas metastasis was confined to the ALK-negative group. Recurrence and metastasis were documented in 50.0% and 25.0% of p53-positive IMTs, respectively, and in 57.1% and 57.1%, respectively, of the p53-negative IMTs. The IMT cases had high recurrence and metastasis and there were significant correlations between histological atypicality and recurrence and metastases, and between absence of ALK reactivity and recurrence. No correlation was found between p53 expression and any clinicopathological feature of IMT.

[Inflammatory myofibroblastic tumor of the larynx]

BACKGROUND/AIM

Inflammatory myofibroblastic tumor (IMT) of the larynx is a rare borderline lesion composed of myofibroblastic and inflammatory cells.

CASE REPORT

We presented a case of 77-year-old male with hoarseness for about three months. Laryngoscopy showed a polypoid tumor originated from the anterior commissure with glottic projection. Grossly, the tumor was 22 x 15 mm, whitish, oval nodus with firm consistency. Histologically, the lesion was composed of spindled to stellate cells arranged in a fascicular to storiform pattern and inflammatory cells: lymphocytes, histiocytes, plasma cells and neutrophils. The stroma was fibromyxoid and collagenous. Immunohistochemically, tumor cells showed strong positivity for actin and vimentin and negativity for cytokeratin, CD34, S100 and desmin. The proliferation (Ki67) was less than 10%.

CONCLUSION

Inflammatory myofibroblastic tumor may be mistaken as a malignancy and the differential diagnosis can be difficult without immunohistochemistry. It is critical to recognize this uncommon entity to avoid unnecessary aggressive treatment.

Asymptomatic inflammatory myofibroblastic tumor of the heart: immunohistochemical profile, differential diagnosis, and review of the literature

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is an uncommon lesion, mainly occurring in children and young adults and extremely rare in the heart. IMTs are composed of differentiated myofibroblastic cells accompanied by inflammatory cells. Cardiac IMTs are considered biologically benign, but they may have fatal consequences depending upon the peculiarity of site. Because of their rarity in the heart, most knowledge is based on extracardiac lesions that have uncertain behaviour.

METHODS AND RESULTS

We investigated the morphologic features and the immunohistochemical profile of an intracardiac IMT, arising in the right outflow tract of an asymptomatic 11-month-old boy, by using a large panel of antibodies, many of them previously reported in extracardiac IMTs only. Results were compared with data of literature. After complete surgical excision of the tumor, the patient is disease-free at 1 year of follow-up.

CONCLUSIONS

The present case showed morphologic and immunohistochemical features characteristic of IMT. Immunohistochemistry was helpful for characterization and differential diagnosis. The immunoreactivity pattern (including calponin expression) was similar to that of extracardiac IMTs except for anaplastic lymphoma kinase 1 immunoreactivity, lacking in this benign intracardiac IMT but usually associated to favourable prognosis in extracardiac IMTs.

Inflammatory myofibroblastic tumor and low-grade myofibroblastic sarcoma: a comparative study of clinicopathologic features and further observations on the immunohistochemical profile of myofibroblasts

Inflammatory myofibroblastic tumor (IMT) and low-grade myofibroblastic sarcoma (LGMS) are intermediate- or low-grade malignant myofibroblastic neoplasms. In this study, the clinicopathologic profiles of 24 IMTs and 10 LGMS were compared with a focus on the immunohistochemical profiles of the neoplastic myofibroblasts. The primary antibodies used in this study were specific for the ultrastructural subcellular components: (1) *-smooth muscle actin (*-SMA), muscle-specific actin (MSA), calponin, and h-caldesmon for myofilaments; (2) fibronectin for fibronexus; (3) laminin for basal lamina; (4) desmin and cytokeratin for intermediate filaments. Anaplastic lymphoma kinase (ALK) alterations were examined by immunohistochemical means, with selective fluorescence in situ hybridization analysis. Histologically, IMT had inhomogeneous microscopic features with multi-component and multi-patterned architecture, whereas LGMS tended to be more uniform in appearance with a higher cellularity, more prominent nuclear hyperchromasia, and a more widely infiltrative growth pattern than IMT. Immunohistochemically, firstly, more than 90% of the cases of both IMT and LGMS expressed calponin, *-SMA, MSA, and fibronectin, almost all with a high expression level, and no cases were positive for h-caldesmon. Secondly, 33.3% (7/21) of IMTs and 40% (4/10) of LGMS were positive for desmin with a low expression level. The positive percentage for laminin was 81.8% (18/22) in IMT, but was 42.9% (3/7) in LGMS with a low expression level. Thirdly, 13.6% (3/22) of IMTs were positive for cytokeratin, but no expression was found in LGMS. ALK staining was found in 40.9% (9/22) of IMTs, and the presence of ALK gene rearrangements was confirmed by fluorescence in situ hybridization in 5 of 6 IMTs examined. However, neither ALK gene rearrangements nor ALK protein labeling was detected in LGMS (0/9). In summary, IMT and LGMS are both composed of cells displaying well-developed myofibroblastic differentiation, which frequently and extensively express actin-associated proteins (*-SMA, MSA, and calponin) and fibronectin, consistent with the ultrastructure markers (myofilaments and fibronectin fibrils). Laminin expression does not exclude a diagnosis of myofibroblastic neoplasms. ALK and cytokeratin, when positive, can be helpful in differentiating IMT from LGMS. LGMS is not a member of the family of ALK-positive tumors.

Pediatric pulmonary tumors: primary and metastatic

Pediatric pulmonary tumors are rare. There is often a significant delay in diagnosis of pulmonary tumors secondary to their rarity and nonspecific presenting physiologic and radiographic findings. A high index of suspicion in pediatric patients with recurrent or persistent pulmonary symptoms is of paramount importance in diagnosing pulmonary tumors at an early stage. Malignant pulmonary tumors are more frequently diagnosed than benign lesions, with metastatic cancers being the most common. Complete surgical resection remains the basis of therapy for primary lesions, and its role in secondary cancers is becoming more established. Adjuvant therapies are frequently employed depending on the precise tumor involved. Mortality rates vary greatly depending on tumor location, stage, and type.

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.

Absence of human herpesvirus-8 in pulmonary inflammatory myofibroblastic tumor: immunohistochemical and molecular analysis of 20 cases

Inflammatory myofibroblastic tumors are uncommon lesions composed of spindled myofibroblasts within a variable background of collagen and inflammatory cells. Although the true nature of these lesions is not fully elucidated, identification of consistent cytogenetic alterations in the anaplastic lymphoma kinase (ALK) gene suggests that they may be neoplastic. A small number of inflammatory myofibroblastic tumors have been reported to harbor human herpesvirus-8 (HHV-8), implicating the virus in its pathogenesis. In this study, 20 cases of pulmonary inflammatory myofibroblastic tumor were analyzed for the presence of HHV-8 with immunohistochemical and molecular methods. In all cases, antibodies to the latent nuclear antigen of the virus were applied. Four open reading frames (ORFs), including ORFs K2, 16, 26, and 72, were targeted utilizing real-time polymerase chain reaction (PCR). The cohort included 9 men and 11 women with a mean age of 37 years (range, 1-81). Microscopically, the tumors were composed of cytologically bland spindle cells with myofibroblastic differentiation. On immunohistochemical studies, 20% of cases (4/20) demonstrated diffuse cytoplasmic positivity with ALK. Immunohistochemical staining for the latent nuclear protein of the virus was negative in all cases (0/20). All tumors (100%, 20/20) tested with real-time PCR were negative for all four ORFs, whereas 100% (10/10) of positive control Kaposi sarcoma cases were positive. Her2 gene expression was present in all (20/20) inflammatory myofibroblastic tumors confirming the presence of amplifiable deoxyribonucleic acid in the tissue lysate. This study documents the absence of HHV-8 in pulmonary inflammatory myofibroblastic tumors, suggesting that further investigation is required to clarify the pathogenesis of this lesion.

Soft tissue tumors of the urinary bladder, Part I: myofibroblastic proliferations, benign neoplasms, and tumors of uncertain malignant potential

Most bladder tumors arise from the urothelium. However, there are several uncommon but significant bladder lesions that must be differentiated from urothelial carcinomas. These include both benign and malignant spindle cell lesions. The first half of this 2-part review will describe benign myofibroblastic proliferations including inflammatory myofibroblastic tumor and postoperative spindle cell nodule; benign neoplasms including leiomyoma, hemangioma, neurofibroma, and schwannoma; and tumors of uncertain malignant potential including paraganglioma, granular cell tumor, and perivascular epithelioid cell tumor. Common clinical presentations, morphological characteristics, and immunohistochemical features are described to aid the practicing pathologist in the identification of these entities. This review also describes current theories as to the pathogenesis of inflammatory myofibroblastic tumor and postoperative spindle cell nodule and details the current molecular markers identifying several of these lesions.

Lower abdominal inflammatory myofibroblastic tumor -an unusual presentation- a case report and brief literature review

A 9-year-old girl presented with lethargy, malaise & chest pain. Her blood counts confirmed hypochromic microcytic anemia. She was prescribed iron supplements. Subsequently she was admitted to our hospital with fever and increasing chest and abdominal pain. She was treated with antibiotics, and a diagnosis of "early chest infection" was made. Over the following 2 weeks she failed to improve, and her anemia worsened. She was readmitted, and found to have a mass in her lower abdomen with pressure symptoms on her bowel and bladder. A white-cell scan showed increased uptake in right lower quadrant. An ultrasound and a CT scan confirmed a mass adjacent to her bladder. Needle biopsy showed it to be an unusual localization of an inflammatory myofibroblastic tumor (IMT) of cecum. A presentation with chest pain, fever, anemia and pressure symptoms was highly unusual of a lower abdominal IMT mass. She had a successful excision of the tumor, with resolution of her symptoms.

A case of an inflammatory myofibroblastic tumor in the lung which expressed TPM3-ALK gene fusion

We herein describe a 4-year-old boy who after being treated for pneumonia showed an abnormal shadow at the hilus of the right lung on chest X-rays with continued inflammatory findings in his laboratory data. CT and MR investigations suggested the existence of a neoplasm at that site. An open biopsy was thus performed for a definite diagnosis. The histological findings and the expression of TPM3-ALK fusion gene confirmed a diagnosis of an inflammatory myofibroblastic tumor. A right upper and middle lobectomy including the tumor was thus performed for a complete resection. In addition to the histological diagnosis, the detection of the tumor specific fusion gene provided objective evidence in making a 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.

Utility of ALK-1 protein expression and ALK rearrangements in distinguishing inflammatory myofibroblastic tumor from malignant spindle cell lesions of the urinary bladder

Inflammatory myofibroblastic tumor of the urinary bladder is an unusual spindle cell neoplasm that displays cytologic atypia, infiltrative growth and mitotic activity mimicking malignant tumors, such as leiomyosarcoma, rhabdomyosarcoma and sarcomatoid carcinoma. The objective of this study was to determine if anaplastic lymphoma kinase (ALK-1) protein expression detected by immunohistochemistry and ALK rearrangements detected by fluorescence in situ hybridization (FISH) were useful in distinguishing inflammatory myofibroblastic tumor from malignant spindle cell tumors of the urinary bladder. In inflammatory myofibroblastic tumor, ALK-1 expression was identified in 13 of 21 cases (62%) and ALK rearrangements in 14 of 21 cases (67%). All cases of inflammatory myofibroblastic tumor demonstrating ALK-1 expression, carried ALK rearrangements. One case negative for ALK-1 expression exhibited ALK rearrangement. ALK rearrangements were more common in women (P=0.0032). Leiomyosarcoma, sarcomatoid carcinoma, embryonal rhabdomyosarcoma and reactive myofibroblastic proliferations were negative for ALK-1 protein and ALK rearrangements. Immunohistochemistry using markers of muscle, epithelial, neural, and follicular dendritic cell differentiation showed overlap between inflammatory myofibroblastic tumor with and without ALK gene rearrangements, and between inflammatory myofibroblastic tumor and spindle cell malignancies. However, coexpression of cytokeratin and muscle-specific antigens was unique to inflammatory myofibroblastic tumor, observed in approximately half the tumors. This study indicates that detection of ALK protein and ALK gene rearrangements are useful in distinguishing inflammatory myofibroblastic tumor from spindle cell malignancies in the urinary bladder. Additionally, our findings suggest that ALK rearrangement is the primary mechanism for ALK activation and that inflammatory myofibroblastic tumor likely represents a heterogeneous group of spindle cell proliferations with the majority associated with ALK translocations, and the remaining associated with other etiologies.

Differential diagnosis of laryngeal spindle cell carcinoma and inflammatory myofibroblastic tumor--report of two cases with similar morphology

Background

Spindle cell tumors of the larynx are rare. In some cases, the dignity is difficult to determine. We report two cases of laryngeal spindle cell tumors.

Case presentation

Case 1 is a spindle cell carcinoma (SPC) in a 55 year-old male patient and case 2 an inflammatory myofibroblastic tumor (IMT) in a 34 year-old female patient. A comprehensive morphological and immunohistochemical analysis was done. Both tumors arose at the vocal folds. Magnified laryngoscopy showed polypoid tumors. After resection, conventional histological investigation revealed spindle cell lesions with similar morphology. We found ulceration, mild atypia, and myxoid stroma. Before immunohistochemistry, the dignity was uncertain. Immunohistochemical investigations led to diagnosis of two distinct tumors with different biological behaviour. Both expressed vimentin. Furthermore, the SPC was positive for pan-cytokeratin AE1/3, CK5/6, and smooth-muscle actin, whereas the IMT reacted with antibodies against ALK-1, and EMA. The proliferation (Ki67) was up to 80% in SPC and 10% in IMT. Other stainings with antibodies against p53, p21, Cyclin D1, or Rb did not result in additional information. After resection, the patient with SPC is free of disease for seven months. The IMT recurred three months after first surgery, but no relapses were found eight months after resurgery.

Conclusion

Differential diagnosis can be difficult without immunohistochemistry. Therefore, a comprehensive morphological and immunohistochemical analysis is necessary, but markers of cell cycle (apart from the assessment of proliferation) do not help.

Absence of human herpesvirus-8 and Epstein-Barr virus in inflammatory myofibroblastic tumor with anaplastic large cell lymphoma kinase fusion gene

Inflammatory myofibroblastic tumor (IMT) is clinically and histologically characterized by inflammation. Some populations of IMT have anaplastic large cell lymphoma kinase (ALK) gene rearrangements. Infection with Epstein-Barr virus (EBV) and human herpesvirus-8 (HHV-8) in tumor cells of IMT has been reported; these reports, however, have been limited to ALK-negative IMT. The purpose of the present paper was to evaluate 21 cases of IMT for the presence of EBV and HHV-8. Immunohistochemically, 15 cases were ALK positive and six were negative. Of eight cases analyzed using reverse transcription-polymerase chain reaction, tropomyosin 3 (TPM3)-ALK, TPM4-ALK and clathrin heavy chain-ALK fusion genes were detected in one, two and two cases, respectively. All 21 IMT, irrespective of ALK expression, were negative for EBV by in situ hybridization for EBV-encoded RNA and immunohistochemical stain for latent membrane antigen-1. HHV-8 was also negative in all IMT by PCR for HHV-8 DNA sequence (KS330/233) and immunohistochemical stain for latent nuclear antigen. These results suggest that IMT may be a heterogeneous group in terms of pathogenesis, and EBV and HHV-8 do not play a major role in the pathogenesis of ALK-positive tumor.

Inflammatory myofibroblastic tumor of the uterus with prominent myxoid change

A surgical case of inflammatory myofibroblastic tumor arising in the uterine corpus and exhibiting prominent myxoid change of the stroma is reported. The patient was a 63-year-old woman with a large tumor mass that filled the uterine cavity and measured 11 cm in maximal dimension. The tumor had a gelatinous appearance and consisted of a loose proliferation of stellate or polygonal cells on a myxomatous background. Fascicular proliferation of spindle cells was also observed focally, and a chronic inflammatory cell infiltration was seen in many areas. Tumor cells had mild atypism and were immunoreactive for vimentin, alpha-smooth muscle actin, and anaplastic lymphoma kinase (ALK). Focal immunoreactivity for high-molecular-weight caldesmon (h-caldesmon) was also noted. The patient has been free from recurrence for 8 months. Inflammatory myofibroblastic tumor of the uterus occasionally shows prominent myxoid change of the stroma, and differentiation from myxoid leiomyosarcoma is problematic in these cases. Based on the immunoreactivity of tumor cells for ALK and h-caldesmon, the present tumor was considered inflammatory myofibroblastic tumor showing a focal phenotypic transition from myofibroblasts to smooth muscle cells.

Pancreatic malignant fibrous histiocytoma, inflammatory myofibroblastic tumor, and inflammatory pseudotumor related to autoimmune pancreatitis: characterization and differential diagnosis

Malignant fibrous histiocytoma (MFH) and inflammatory myofibroblastic tumor (IMT) are uncommon primary non-epithelial cell tumors of the pancreas. In addition, there are inflammatory pseudotumors (IPT) that may arise in the course of autoimmune pancreatitis (AIP). In the English language literature, only 24 cases of IMT and nine cases of MFH in the pancreas have been reported to date. We investigated three individual spindle cell tumors of the pancreas that were identified as MFH, IMT, and IPT, respectively, using immunohistochemical and molecular analysis. Both the MFH and the IMT, but not the IPT, showed nuclear p53 expression and mutations of the p53 gene. The MFH and the IMT also had higher mitotic and Ki-67 (MIB-1) indexes than the IPT. The IPT was found to be a tumor-like case of AIP. Many IgG4-positive plasma cells, which are considered to be a feature of AIP, were found in all three tumors. It is concluded that in this series of spindle cell tumors of the pancreas, apart from immunohistochemical features, the demonstration of p53 mutations may be helpful in distinguishing true neoplastic tumors from pseudotumors such as IPTs arising in the context of AIP.

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 in children: clinical review with anaplastic lymphoma kinase, Epstein-Barr virus, and human herpesvirus 8 detection analysis

BACKGROUND/PURPOSE

Inflammatory myofibroblastic tumor (IMT) is considered as an intermediate neoplasm that may present malignant features. Differential diagnosis with other tumor processes is sometimes difficult. Similar anaplastic lymphoma kinase (ALK) gene abnormalities as in anaplastic large cell lymphoma have been reported. Human herpesvirus 8 (HHV-8) DNA sequences have been described in adult pulmonary IMTs and Epstein-Barr virus (EBV) has been reported in splenic and hepatic IMTs, suggesting the importance of both viruses in IMT development. This article aims to evaluate ALK, EBV, and HHV-8 expression in children with IMT and to correlate our findings with clinical features.

METHODS

Sixteen children (range, 1-15 years) who had surgery for IMT between 1978 and 2003 were evaluated retrospectively. Formalin-fixed, paraffin-embedded archival tissues were stained for HHV-8 and ALK with immunohistochemistry. Epstein-Barr virus was detected by in situ hybridization (EBER probes).

RESULTS

Tumors were located in the pulmonary lobe (n = 4), urinary tract (n = 4), mesentery or bowel (n = 4), hepatic lobe (n = 1), vena cava (n = 1), spinal cord (n = 1), and soft tissue (n = 1). Five children were treated with steroids and/or antibiotics before surgery, with no substantial result. IMT was excised totally in all but 2 cases. Four patients presented aggressive IMT with recurrence or metastasis requiring new surgery. ALK was positive in 3 (18.8%) cases and EBV in 1 pulmonary and 1 bladder tumor, all of them without recurrence or metastasis. None of the cases were positive for HHV-8. All patients are now disease-free with a mean follow-up of 4.2 years.

CONCLUSIONS

Considering the present lack of efficient medical treatment, surgery should still be considered as the mainstay therapy in IMT, even in cases of recurrence or metastases. Larger multicentric studies would be necessary to understand the prognostic significance of ALK, EBV, and HHV-8 and their relationships with the origins of the tumor.