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

Can Chemotherapy Facilitate Less Morbid Surgery in Multicentric Intra-abdominal Inflammatory Myofibroblastic Tumor?

BACKGROUND

Inflammatory myofibroblastic tumor is a rare benign neoplasm affecting young adults and children. Although often considered benign, its locally aggressive nature and tendency to recur make its management immensely challenging, particularly without robust evidence to guide treatment. Surgical excision offers the best hope for a cure; however, this can lead to significant morbidity and may not always be possible, especially for multicentric diseases.

CASE PRESENTATION

We report a multicentric abdominal inflammatory myofibroblastic tumor in a 6-year-old girl who presented with massive abdominal distention. The sheer size of the mass, coupled with multicentric presentation and absent mobility on clinical examination, would have led to a very morbid surgical exploration. This patient was treated with initial chemotherapy, which led to a dramatic response in both symptoms and size of masses, facilitating a complete surgical resection with negligible postoperative morbidity.

CONCLUSIONS

Although surgery is the preferred treatment for a resectable disease, initial chemotherapy for multicentric or locally advanced inflammatory myofibroblastic tumors facilitates complete surgical resection.

Therapeutic strategy and prognostic analysis of inflammatory myofibroblastic tumor in the head and neck: a retrospective study

Objective

This study aimed to investigate the clinical features, treatment methods, and prognosis of head and neck inflammatory myofibroblastic tumor (HNIMT).

Methods

A retrospective analysis was conducted using the clinical data of 12 HNIMT patients who were admitted to Shanxi Cancer Hospital between January 2016 and December 2023. This analysis focused on their clinical manifestations, pathological characteristics, treatment strategies, and prognosis.

Results

Among the 12 cases analyzed, four involved inflammatory myofibroblastic tumors (IMT) located in the nasal sinuses or nasopharynx, with symptoms including nasal congestion, rhinorrhea, and maxillofacial swelling. Two cases each in the salivary glands and oral cavity presented as localized, painless masses. One right cervical IMT case also presented as a painless lump. Two laryngeal IMT cases had hoarseness, and one subglottic endotracheal IMT case showed inspiratory dyspnea. All patients received surgery, with postoperative pathology confirming IMT. During follow-up, four cases recurred. Finally, nine patients were disease-free, two survived with disease, and one died.

Conclusions

HNIMT is a rare, low-grade malignant or borderline tumor that is generally associated with a favorable prognosis. Accurate diagnosis relies on pathological examination, and surgical resection remains the primary treatment for HNIMT. The need for adjuvant therapy following surgery should be determined by clinicians based on tumor location, surgical approach, and the presence of high-risk factors.

Inflammatory Myofibroblastic Tumor: An Updated Review

Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm that is characterized by a proliferation of myofibroblastic and fibroblastic spindle cells, accompanied by an inflammatory infiltrate that is abundant in plasma cells, lymphocytes, and eosinophils. IMT can arise in various anatomical locations but most commonly occurs in the abdominal cavity, retroperitoneum, and lung, particularly in children and young adults. IMT typically demonstrates local invasion or recurrence, whereas metastasis is rare. IMTs pose a diagnostic challenge because of their overlapping morphological characteristics with a heterogeneous group of nonneoplastic and neoplastic lesions. Precise diagnosis is crucial for optimal management and accurate prognostication. Despite recent advancements in IMT diagnosis and treatment, its biological complexity and clinical management remain challenging due to significant histological heterogeneity and molecular genetic diversity. This review provides comprehensive updates on the clinical, molecular, and pathological characteristics of IMT, highlighting the diagnostic approaches and key differential diagnoses.

Inflammatory myofibroblastic tumor in the liver after bone marrow transplantation: case report and literature review

Introduction

Inflammatory myofibroblastic tumor (IMT) is a rare low-grade malignant neoplasm in the liver. Timely diagnosis and treatment of IMT are challenging due to its atypical symptoms and imaging results.

Case report

We report a 46-year-old woman who presented to our hospital with persistent hyperpyrexia and discomfort in the right upper abdomen for 2 months post bone marrow transplantation. Radiological findings revealed a space-occupying lesion of uncertain nature in the liver. Since the histological examination of the biopsy specimen indicated IMT, she underwent surgical resection. Subsequently, the postoperative pathology confirmed the diagnosis of IMT. The patient's febrile condition subsided after the surgery. A magnetic resonance imaging (MRI) scan performed 8 months later showed no signs of recurrence.

Conclusion

IMTs are caused by genetic rearrangements. Diagnosing IMT can be challenging especially in this case as we had to differentiate the tumor from inflammatory diseases associated with bone marrow transplantation. Hence, a thorough pathological immunohistochemical examination is required to confirm its diagnosis. Local IMTs should be treated with radical surgical resection. In cases of distant metastasis or incomplete resection cases, chemotherapy, targeted therapy, or immunotherapy can be utilized. Regular follow-up is crucial for improving the patient's survival rate.

Methotrexate resistance and its regulatory mechanisms in pediatric tumors and beyond

Methotrexate (MTX) is a critical antimetabolite drug in treating various pediatric diseases, including acute lymphoblastic leukemia (ALL), non-Hodgkin lymphoma (NHL), brain tumors, osteosarcoma, inflammatory myofibroblastic tumor (IMT), juvenile scleroderma (JS), and juvenile idiopathic arthritis (JIA). MTX acts as a folate antagonist by inhibiting dihydrofolate reductase (DHFR), an enzyme essential for the synthesis of tetrahydrofolate. This disruption impairs DNA synthesis, repair, and cellular replication, particularly affecting rapidly dividing cells. Despite its efficacy, MTX resistance poses significant challenges, particularly in pediatric oncology, where it undermines the ability to achieve sustained therapeutic effects, resulting in reduced therapeutic efficacy and poor prognosis. The mechanisms of MTX resistance encompassed reduced enzyme activity pivotal for MTX metabolism, enhanced expression of efflux transporters, genetic variations, and alterations in signaling pathways. Multifaceted strategies have been explored to overcome MTX resistance. Combination therapies with ginger extract, gold nanoparticles, and arsenic trioxide (ATO) have been investigated to augment MTX's cytotoxic effects. Synergies with mTOR inhibitors and MDM2 inhibitors have demonstrated enhanced outcomes in ALL. In JIA, targeting ATP-binding cassette (ABC) transporters and modulating transforming growth factor‑β (TGF-β) signaling pathways have emerged as promising approaches. For osteosarcoma, emphasis on autophagy pathways and non-coding RNAs influencing chemotherapy sensitivity could enhance MTX effectiveness. This review delineates MTX's therapeutic roles, elucidates its resistance mechanisms, and discusses current and potential strategies for managing MTX resistance to bolster treatment effectiveness in pediatric tumors and other diseases. This knowledge base could underpin further research and development of personalized treatments to optimize MTX's clinical benefits.

Lorlatinib for the Treatment of Inflammatory Myofibroblastic Tumor after Allogeneic Hematopoietic Stem Cell Transplantation

Inflammatory myofibroblastic tumors (IMTs) are rare sarcomas composed of myofibroblastic and fibroblastic cells, accompanied by inflammatory cell infiltration. Many IMTs exhibit clonal rearrangement of anaplastic lymphoma kinase (ALK). We herein report a 56-year-old woman with uterine IMT harboring a thrombospondin-1::ALK fusion that developed after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Laboratory data before systemic therapy indicated increased interleukin-6 and severe leukocytosis. The patient was treated with lorlatinib; however, the response duration was approximately two months. Similar case reports need to be compiled and evaluated to elucidate the efficacy of lorlatinib in post-allo-HSCT IMT with ALK rearrangement.

Mesenteric inflammatory myofibroblastic tumor (IMT), a rare neoplasm in a pediatric patient: imaging findings and literature review

Inflammatory myofibroblastic tumors (IMTs) are rare neoplasms commonly classified as having "intermediate malignancy" due to their unique clinical, pathological, and molecular features. These tumors can exhibit aggressive biological behavior, including local invasion, recurrence, and, on rare occasions, distant metastasis. IMTs may arise in various anatomical locations, with the lung, mesentery, and omentum being the most frequent sites. Although IMTs can occur at any age, they are more commonly diagnosed in children and young adults. Their clinical manifestations and imaging findings are often nonspecific and may resemble malignant pathology, making diagnosis challenging. Moreover, the histopathological characteristics of IMTs can overlap with those of other conditions. In this report, we present a case of multicentric abdominal IMT in a pediatric patient and review the imaging features of abdominal IMTs in children, as documented in the limited number of available cases. Accurate differential diagnosis requires a comprehensive understanding of both the clinical presentation and radiographic features of these tumors. Radiologists should be familiar with the distinctive imaging characteristics of IMTs to ensure that this rare pathology is considered in the differential diagnosis of any abdominal mass in pediatric patients.

Chinese Expert Consensus on the Diagnosis and Treatment of Inflammatory Myofibroblastic Tumor

Inflammatory myofibroblastic tumor (IMT) is a rare spindle-cell neoplasm. IMT currently suffers from a paucity of standardized diagnostic and therapeutic guidelines. The Chinese expert consensus committee on the diagnosis and treatment of IMT formed an "Expert consensus on the diagnosis and treatment of inflammatory myofibroblastic tumor". This consensus was developed through a comprehensive synthesis of expert opinions, an extensive review of the literature, and a series of offline and online deliberations. The committee aspires that this consensus will enhance the therapeutic outcomes and prognosis for patients with IMT in the future.

Partial response to lorlatinib in thoracic inflammatory myofibroblastic tumor harboring complex and rare ALK fusions: a case report

Background

Targeted therapy has dramatically altered the treatment paradigm for some patients with inflammatory myofibroblastic tumor (IMT) that possesses specific molecular aberrations. IMT is an exceedingly rare type of sarcoma, with about 50% of cases featuring anaplastic lymphoma kinase (ALK) gene rearrangements. The treatment of IMT with ALK fusions using ALK tyrosine kinase inhibitors (TKIs) has become increasingly common. However, until now, there is a lack of evidence supporting the efficacy of third-generation ALK-TKIs in this disease category.

Case Description

Here, we report the first case of a patient with advanced IMT harboring the EML4-ALK fusion gene along with two rare ALK fusion genes: PLB1-ALK, which has only been reported in two cases of lung adenocarcinoma and large cell neuroendocrine carcinoma, and unreported ALMS1-ALK. The patient achieved partial response (PR) following first-line treatment with lorlatinib and subsequently underwent successful surgical intervention.

Conclusions

This is the inaugural case of a third-generation ALK-TKI achieving therapeutic success in advanced IMT with complex ALK rearrangements, including rare and previously uncharacterized fusion subtypes. Although the biological functions of these two rare ALK fusions still need to be confirmed, this case underscores the dependency of ALK-rearranged IMT on ALK-mediated signaling, suggesting that third-generation ALK-TKIs may offer an optimal targeted therapeutic strategy for ALK-dependent mesenchymal tumor subtypes.

Identification of the molecular characterization and tumor microenvironment of thoracic inflammatory myofibroblastic tumors

BACKGROUND

Inflammatory myofibroblastic tumors (IMTs), rare soft tissue neoplasms, are characterized by a blend of myofibroblastic proliferation and inflammatory features. While generally characterized by slow growth, IMTs can exhibit locally aggressive behavior, and in rare instances, metastasize to distant sites. This study elucidated the clinical characteristics, molecular profile, and tumor microenvironment of thoracic IMTs.

METHODS

We retrospectively analyzed cases of IMTs diagnosed at the National Taiwan University Hospital between 2000 and 2020. ALK immunohistochemistry (IHC) was performed, followed by fluorescence in situ hybridization (FISH) for confirmation. Next-generation sequencing (NGS) was employed to detect unknown oncogenic drivers, and multiplex immunofluorescence staining was used to characterize the tumor microenvironment. Demographic, clinicopathological characteristics, and treatment outcomes were systematically recorded and analyzed.

RESULTS

We identified a total of 8 patients with thoracic IMTs, whose median age of the participants was 33.8 years (range: 18.6-58.7). The disease status of all tumors were early-stage, and all patients underwent surgical excision. ALK fusions were detected in 6 tumors (all spindle-cell patterns), with fusion partners including 3 TPM3, 2 DCTN1, and one EML4. In the remaining 2 tumors without ALK fusion, NGS showed NTRK3 alteration with high gene expressions. Multiplex IHC of three cases identified a pronounced infiltration of macrophages cells within the tumor microenvironment.

CONCLUSION

Patients with thoracic IMT patients are typically young with early-stage disease. ALK fusion were the most common genetic alteration, particularly in spindle-cell patterns. Characterization of the tumor microenvironment indicates the potential of immune profiling in the tumor biology and targeted immunotherapy approaches.

Efficacy of core biopsies for diagnosing inflammatory myofibroblastic tumors in pediatric patients: case series from a single tertiary referral center

Background

Inflammatory myofibroblastic tumors (IMTs) are rare, often non-metastasizing neoplasms characterized by fibro/myofibroblastic spindle cells with varying infiltrates of plasma cells, lymphocytes, and/or eosinophils. Despite their generally indolent nature, IMTs can exhibit locally aggressive behavior and a significant tendency for local recurrence, making complete surgical resection the standard treatment approach. Accurate diagnosis can be challenging due to the overlap in imaging features with more aggressive tumors, necessitating preoperative biopsies to enable differential diagnosis and guide treatment decisions. The complexity of distinguishing IMTs from other malignancies underscores the importance of biopsy in establishing an accurate diagnosis and planning appropriate management strategies.

Case Description

This study presents the cases of four pediatric patients (three males, one female) diagnosed with IMT, involving tumors located in the lung (one case), bladder (one case), and liver (two cases). Initial minimally invasive biopsies, including a US-guided tru-cut core biopsy and a percutaneous core biopsy in one case, as well as endoscopic core biopsies in two other cases, yielded inconclusive results. These initial procedures failed to provide definitive diagnostic information, necessitating the use of more precise diagnostic techniques to achieve a definitive histological diagnosis of IMT.

Conclusions

The findings indicate that when initial biopsy results are inconclusive in cases suspected to be IMT, more precise diagnostic procedures may be necessary to secure a definitive diagnosis. This highlights the need for careful consideration of alternative biopsy methods to ensure accurate identification and effective management of IMT in pediatric patients.

Progress in histology specific treatments in soft tissue sarcoma

INTRODUCTION

Soft tissue sarcomas (STS) represent a heterogenous group of rare tumors, primarily treated with surgery. Preoperative radiotherapy is often recommended for extremity high-risk STS. Neoadjuvant chemotherapy, typically based on doxorubicin with ifosfamide, has shown efficacy in limbs and trunk wall STS. Second-line chemotherapy, commonly utilized in the metastatic setting, is mostly histology-driven. Molecular targeted agents are used across various histologies, and although the use of immunotherapy in STS is still in its early stages, there is increasing interest in exploring its potential.

AREAS COVERED

This article involved an extensive recent search on PubMed. It explored the current treatment landscape for localized and metastatic STS, focusing on the combined use of radiotherapy and chemotherapy for both extremity and retroperitoneal tumors, and with a particular emphasis on the most innovative histopathology driven therapeutic approaches. Additionally, ongoing clinical trials identified via clinicaltrials.gov are included.

EXPERT OPINION

Recently there have been advancements in the treatment of STS, largely driven by the outcomes of clinical trials. However further research is imperative to comprehend the effect of chemotherapy, targeted therapy and immunotherapy in various STS, as well as to identify biomarkers able to predict which patients are most likely to benefit from these treatments.

Ibero-American Consensus for the Management of Peritoneal Sarcomatosis: Updated Review and Clinical Recommendations

Peritoneal sarcomatosis is a rare malignant disease with a poor prognosis, secondary to peritoneal dissemination of abdominopelvic soft tissue sarcomas. Its rarity, together with the characteristic histological heterogeneity and the historically poor response to systemic treatments, has prevented the establishment of widely accepted treatment criteria with curative intent. In this sense, radical cytoreductive surgery (CRS) with peritonectomy procedures and hyperthermic intraperitoneal chemotherapy (HIPEC), widely used in peritoneal carcinomatosis with excellent results, have not had the same evolutionary development in patients with peritoneal sarcomatosis. A multidisciplinary working group of experts in sarcomas and peritoneal oncological surgery established a series of recommendations based on current scientific evidence for the management of peritoneal sarcomatosis, taking into account the different histological subgroups of abdominopelvic sarcomas that can cause it depending on their origin: retroperitoneal sarcomas, uterine sarcomas, and visceral/peritoneal sarcomas of GIST (gastrointestinal stromal tumor) and non-GIST origin. This article shows the results of sarcoma experts' voting on the recommendations presented during the I Ibero-American Consensus on the Management of Peritoneal Sarcomatosis, which took place during the recent celebration of the III Hispanic-Portuguese Meeting for Updates on the Treatment of Sarcomas.

Inflammatory myofibroblastic tumor from molecular diagnostics to current treatment

Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm with intermediate malignancy characterized by a propensity for recurrence but a low metastatic rate. Diagnostic challenges arise from the diverse pathological presentation, variable symptomatology, and lack of different imaging features. However, IMT is identified by the fusion of the anaplastic lymphoma kinase (ALK) gene, which is present in approximately 70% of cases, with various fusion partners, including ran-binding protein 2 (RANBP2), which allows confirmation of the diagnosis. While surgery is the preferred approach for localized tumors, the optimal long-term treatment for advanced or metastatic disease is difficult to define. Targeted therapies are crucial for achieving sustained response to treatment within the context of genetic alteration in IMT. Crizotinib, an ALK tyrosine kinase inhibitor (TKI), was officially approved by the US Food and Drug Administration (FDA) in 2020 to treat IMT with ALK rearrangement. However, most patients face resistance and disease progression, requiring consideration of sequential treatments. Combining radiotherapy with targeted therapy appears to be beneficial in this indication. Early promising results have also been achieved with immunotherapy, indicating potential for combined therapy approaches. However, defined recommendations are still lacking. This review analyzes the available research on IMT, including genetic disorders and their impact on the course of the disease, data on the latest targeted therapy regimens and the possibility of developing immunotherapy in this indication, as well as summarizing general knowledge about prognostic and predictive factors, also in terms of resistance to systemic therapy.

Inflammatory myofibroblastic tumor of the heart in an older woman with paroxysmal atrial fibrillation: a case report and review of the literature

Inflammatory myofibroblastic tumors (IMTs) of the heart are rarely observed in the eldly. We report a case involving an elderly woman with an IMT situated on the right atrial wall. The tumor was fully excised. The patient had a smooth recovery post-surgery and remained free of recurrence for three years.

AM1172 (a hydrolysis-resistant endocannabinoid analog that inhibits anandamide cellular uptake) reduces the viability of the various melanoma cells, but it exerts significant cytotoxic effects on healthy cells: an in vitro study based on isobolographic analysis

BACKGROUND

Despite great advances in our understanding of the impact of cannabinoids on human organism, many of their properties still remain undetermined, including their potential antineoplastic effects. This study was designed to assess the anti-proliferative and cytotoxic effects of AM1172 (a hydrolysis-resistant endocannabinoid analog that inhibits anandamide cellular uptake) administered alone and in combinations with docetaxel (DOCX), paclitaxel (PACX), mitoxantrone (MTX) and cisplatin (CDDP) on various human malignant melanoma A375, FM55P, SK-MEL 28 and FM55M2 cell lines.

MATERIALS

In the MTT, LDH, and BrdU assays, the potency and safety of AM1172 when administered alone and in combinations with DOCX, PACX, MTX, and CDDP were determined.

RESULTS

The isobolographic analysis revealed that combinations of AM1172 with PACX, DOCX, MTX, and CDDP exerted additive interactions, except for a combination of AM1172 with PACX in primary melanoma A375 cell line, for which synergy was observed (*p<0.05). Nevertheless, AM1172 when administered alone produced cytotoxic effects on healthy human melanocytes (HEMa-LP) and human keratinocytes (HaCaT), which unfortunately limits its potential therapeutic utility.

CONCLUSIONS

AM1172 cannot be used separately as a chemotherapeutic drug, but it can be combined with PACX, DOCX, MTX, and CDDP, offering additive interactions in terms of the anti-proliferative effects in various malignant melanoma cell lines.

Inflammatory myofibroblastic tumor of the upper arm: A case report

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is an uncommon benign myofibroblastic tumor that usually occurs in the lung, mediastinum, abdomen and vulvovaginal region. IMT of the upper arm is exceedingly rare with unknown etiology. Pathology plays a major role in the diagnosis of IMT, and radiological characteristics of the condition are crucial for differential diagnosis.

PATIENT CONCERNS

A 62-year-old woman was admitted to our hospital for a complaint of a mass in her left upper limb with progressive numbness in the extremity. Ultrasound examination of the brachial artery (BA) revealed a hypoechoic mass with well-defined borders and a substantial blood flow, and the mass was also shown to be greatly enhanced on computed tomography (CT) and magnetic resonance imaging (MRI).

DIAGNOSIS

The subsequent histopathological and immunohistochemical studies led to the diagnosis of IMT.

INTERVENTION

The patient was referred for surgery. The soft tissue tumor resection, left median nerve release operation, brachial artery vascular grafting, and arterial anastomosis were performed.

OUTCOME

Favorable outcome was observed. The patient recovered well from the procedure and did not experience any further complications or tumor recurrence.

LESSONS

In this report, we describe a case of IMT of the upper arm with BA involvement. The case expands the differential diagnosis of limb neoplasm and broadens the understanding of its ultrasonic and radiological imaging features. It also serves as a further example of an uncommon region distinct from conventional IMT. Further studies on the etiology and therapeutic strategies are needed.

Diagnosis of inflammatory myofibroblastic tumor in a pediatric patient initially suspected of tuberculosis

BACKGROUND

Symptoms of inflammatory myofibroblastic tumor (IMT) are atypical, and histopathological misdiagnosis of IMT is still inevitable. Here we present a pediatric case that an eight-year-old boy with recurrent fever for fifteen months, received anti-tuberculosis therapy for five months and was ultimately confirmed to be IMT.

CASE PRESENTATION

An eight-year-old boy experienced a recurrent fever for fifteen months, accompanied by cough, vomiting, meteorism, night sweating, and emaciation. Thoracoabdominal computer tomography revealed multiple enlarged lymph nodes in the thorax, abdomen, and axilla, as well as minimal bilateral pleural effusion. Histopathological examinations of the intestines and greater omentum implied fibrous tissue hyperplasia along with eosinophil and lymphocyte infiltration. The patient was initially misdiagnosed with tuberculosis, and symptoms were relieved partially following anti-tuberculosis treatment. However, after four months, the symptoms aggravated again and a subsequent histopathological analysis of a second sample from the greater omentum revealed the presence of IMT. Eventually, after surgical resection of the lesions and chemotherapy, the clinical symptoms in the child gradually alleviated.

CONCLUSIONS

The clinical course of IMT is variable, and pediatricians should pay attention to differentiating IMT from tuberculosis.

Inflammatory myofibroblastic tumors: recent progress and future of targeted therapy

An inflammatory myofibroblastic tumor is a rare component of bone and soft-tissue sarcomas that has distinct pathological features as a lymphoplasmacytic inflammatory infiltrate. As is the case for other non-small round cell sarcomas, surgical resection remains the standard treatment strategy for inflammatory myofibroblastic tumors, but recurrence is possible. Concerning systemic therapy, the available data for conventional chemotherapy (such as those of doxorubicin-based regimens) are limited, and case reports of anti-inflammatory inflammatory myofibroblastic tumor treatments describe some degree of symptom relief and efficacy against tumor progression. However, as more information about cancer genomics accumulates, the potential for molecularly targeted therapies for inflammatory myofibroblastic tumors has become more promising. Approximately half of inflammatory myofibroblastic tumors harbor anaplastic lymphoma kinase (ALK) fusion genes, and the other half could have potentially targetable fusion genes or mutations such as ROS1, NTRK and RET; case reports demonstrating the clinical efficacy of treatments targeted to inflammatory myofibroblastic tumor have been published, as have several prospective clinical trials. Few drugs are approved for the treatment of inflammatory myofibroblastic tumor, and most of them were approved for tumor-agnostic indications. Drugs that could be used for pediatric indications and dosing in inflammatory myofibroblastic tumor have also not been established. To provide effective targeted therapy for rare diseases such as inflammatory myofibroblastic tumor, it is necessary to obtain clinical evidence by designing and performing clinical trials and to find a path toward regulatory approval.

Inflammatory Myofibroblastic Tumor With ROS1 Gene Fusions in Children and Young Adolescents

PURPOSE

Inflammatory myofibroblastic tumors (IMTs) are often driven by anaplastic lymphoma kinase fusions and less frequently by alternative fusions such as ROS1. We describe the clinical characteristics, treatment approach, and outcome for a series of young patients with IMTs and ROS1 alterations.

METHODS

This was a retrospective, international, multicenter study analyzing young patients (younger than 21 years) with ROS1-altered IMTs treated in 10 European referral centers between 2014 and 2022. Patients were included in the European pediatric Soft tissue sarcoma Study Group NRSTS-2005 protocol or registered in the Soft Tissue Sarcoma Registry. Primary surgery was recommended if a microscopic radical resection was feasible without mutilation. No standard systemic treatment protocol was available, but several medical options were recommended.

RESULTS

A total of 19 patients (median age 8.3 years) were included. Most patients had a biopsy at diagnosis (Intergroup Rhabdomyosarcoma Study [IRS] I; n = 2, IRS II; n = 1, IRS III biopsy; n = 11, IRS III resection; n = 3, IRS IV; n = 2). Twelve patients received neoadjuvant systemic therapy in first line (four received multiple treatments): high-dose steroids (n = 2), vinorelbine/vinblastine with methotrexate (n = 6), or ROS1 inhibitors (n = 8). After a median follow-up of 2.8 years (range, 0.2-13.4), seven patients developed an event. The 3-year event-free survival was 41% (95% CI, 11 to 71), and the 3-year overall survival was 100%.

CONCLUSION

Outcome for ROS1-altered IMTs appears excellent. A complete resection at diagnosis was often not feasible, and most patients needed neoadjuvant therapy. Patients who developed a tumor event could be cured with reinitiation of systemic therapy and/or surgery. This approach illustrates a switch in treatment philosophy moving from immediate, often mutilating, surgery to systemic (targeted) therapy as a bridge to more conservative surgery later in the treatment course.

Retrospective observational studies in ultra-rare sarcomas: A consensus paper from the Connective Tissue Oncology Society (CTOS) community of experts on the minimum requirements for the evaluation of activity of systemic treatments

BACKGROUND

In ultra-rare sarcomas (URS) the conduction of prospective, randomized trials is challenging. Data from retrospective observational studies (ROS) may represent the best evidence available. ROS implicit limitations led to poor acceptance by the scientific community and regulatory authorities. In this context, an expert panel from the Connective Tissue Oncology Society (CTOS), agreed on the need to establish a set of minimum requirements for conducting high-quality ROS on the activity of systemic therapies in URS.

METHODS

Representatives from > 25 worldwide sarcoma reference centres met in November 2020 and identified a list of topics summarizing the main issues encountered in ROS on URS. An online survey on these topics was distributed to the panel; results were summarized by descriptive statistics and discussed during a second meeting (November 2021).

RESULTS

Topics identified by the panel included the use of ROS results as external control data, the criteria for contributing centers selection, modalities for ensuring a correct pathological diagnosis and radiologic assessment, consistency of surveillance policies across centers, study end-points, risk of data duplication, results publication. Based on the answers to the survey (55 of 62 invited experts) and discussion the panel agreed on 18 statements summarizing principles of recommended practice.

CONCLUSIONS

These recommendations will be disseminated by CTOS across the sarcoma community and incorporated in future ROS on URS, to maximize their quality and favor their use as control data when results from prospective studies are unavailable. These recommendations could help the optimal conduction of ROS also in other rare tumors.

Treatment, pathological characteristics, and prognosis of pulmonary inflammatory myofibroblastic tumor–a retrospective study of 8 cases

Objective

Inflammatory myofibroblastic tumor (IMT) is a rare disease. We reviewed data from eight patients diagnosed with pulmonary IMT (PIMT) at our hospital with the aim of summarizing and analyzing the characteristics of PIMT to improve our understanding of the disease.

Methods

From January 2012 to December 2019, eight patients underwent surgical intervention for PIMT at The First Affiliated Hospital of Bengbu Medical College. Resected tumors were subjected to pathological and immunohistochemical analyses. The follow-up duration for all patients ranged from 2 years and 3 months to 9 years and 9 months (median: 6 years and 9 months).

Results

The male:female ratio was 5:3, and the mean age was 48.50 years (21–74 years). Two patients (25%) with lung disease discovered via chest computed tomography during physical examinations had not experienced any symptoms. Six patients (75%) presented at the hospital because of cough, expectoration, blood in sputum, and chest tightness. Lesions from all eight patients were surgically removed, and PIMT was confirmed based on pathological examinations and immunohistochemical results. No patient received additional treatment after discharge. All cases have been followed up to the time of writing, without any tumor recurrence or distant metastasis.

Conclusion

The age of onset of PIMT is usually over 40 years, and its clinical symptoms are easily confused with those of lung cancer. PIMT can only be diagnosed by histopathology and immunohistochemistry. Complete surgical resection is the preferred treatment, as patients undergoing surgery require no additional treatment, such as chemotherapy, and the survival rate is good.

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.

Locally Advanced Inflammatory Myofibroblastic Tumor Treated With Targeted Therapy: A Case Report and Literature Review

Inflammatory myofibroblastic tumors (IMTs) are known to be associated with anaplastic lymphoma kinase (ALK) gene rearrangements. Other molecular alterations such as ROS proto-oncogene 1, receptor tyrosine kinase (ROS1), neurotrophic tyrosine receptor kinase (NTRK), and platelet-derived growth factor receptor (PDGFR) have also been identified in IMTs. Although there are no randomized controlled clinical trials comparing chemotherapy, tyrosine kinase inhibitors (TKIs), or other systemic therapies, the literature demonstrates the use of ALK-targeted TKIs as an effective strategy for the treatment of locally advanced or metastatic ALK-rearranged IMTs. This case report describes a patient with an ALK-rearranged locally advanced pulmonary IMT who was treated with neoadjuvant-intent crizotinib. The patient had a very favorable response to therapy, and surgery was declined. It is difficult to determine the duration and sequencing of TKI use in these settings as there is little published data to guide decisions. This report also includes a comprehensive compilation of published IMT cases with molecular alterations treated with systemic therapy, which also highlighted the duration of therapies and clinical outcomes.

Inflammatory Myofibroblastic Tumor: A Multi-Institutional Study from the Pediatric Surgical Oncology Research Collaborative

Inflammatory myofibroblastic tumor (IMT) is a mesenchymal neoplasm of intermediate malignancy. We describe the largest cohort of IMT patients to date, aiming to further characterize this rare, poorly understood tumor. This is a multi-institutional review of IMT patients ≤39 years, from 2000-2018, at 18 hospitals in the Pediatric Surgical Oncology Research Collaborative. 182 patients were identified with median age of 11 years. 33% of tumors were thoracic in origin. Presenting signs/symptoms included pain (29%), respiratory symptoms (25%), and constitutional symptoms (20%). Median tumor size was 3.9 cm. Anaplastic lymphoma kinase (ALK) overexpression was identified in 53% of patients. 7% of patients had distant disease at diagnosis. 91% of patients underwent resection: 14% received neoadjuvant treatment and 22% adjuvant treatment. 12% of patients received an ALK inhibitor. 66% of surgical patients had complete resection, with 20% positive microscopic margins, and 14% gross residual disease. Approximately 40% had en bloc resection of involved organs. Median follow-up time was 36 months. Overall 5-year survival (OS) was 95% and 5-year event-free survival (EFS) was 80%. Predictors of recurrence included respiratory symptoms, tumor size, and distant disease. Gross or microscopic margins were not associated with recurrence, suggesting that aggressive attempts at resection may not be warranted. This article is protected by copyright. All rights reserved.

Treatment of Pediatric Inflammatory Myofibroblastic Tumor: The Experience from China Children’s Medical Center

Background: Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor with intermediate malignancy that tends to affect children primarily. To date, no standardized therapies exist for the treatment of IMT. This study aimed to share experience from China Children’s Medical Center for the explorative treatment of IMT. Methods: Patients with newly diagnosed IMT between January 2013 and December 2018 were included. Patients were grouped according to surgical margins and Intergroup Rhabdomyosarcoma Study Group (IRSG) staging. The clinical characteristic, therapeutic schedules, treatment response and clinical outcome were described. Results: Six patients were enrolled in this study, including two boys and four girls, with a median age of 57 months (range 10–148 months). Among them, five patients were anaplastic lymphoma kinase positive. Four patients achieved complete remission and two patients attained partial remission after treatment with this protocol. All patients were alive after a median follow-up of 4 years (range 3–7 years). The most common treatment-related adverse reaction was myelosuppression. Conclusion: In this study, we demonstrated that IMT has a good prognosis and the treatment selected according to risk stratification was effective and feasible.

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.

Long-term efficacy update of crizotinib in patients with advanced, inoperable inflammatory myofibroblastic tumour from EORTC trial 90101 CREATE

PURPOSE

European Organisation for Research and Treatment of Cancer (EORTC) 90101 (CREATE) was a prospective, multicentric, non-randomised, open-label phase II basket trial to assess the efficacy and safety of crizotinib in patients with different types of cancers, including advanced inflammatory myofibroblastic tumour (IMT) with or without anaplastic lymphoma kinase (ALK) rearrangements. Here, we report updated results with long-term follow-up.

PATIENTS/METHODS

After central reference pathology, eligible ALK-positive and ALK-negative patients with advanced/metastatic IMT deemed incurable with surgery, radiotherapy or systemic therapy received oral crizotinib 250 mg twice daily. The ALK status was assessed centrally using immunohistochemistry and fluorescence in situ hybridisation. The primary end-point was the proportion of patients who achieved an objective response (i.e. complete or partial response). If ≥6 ALK-positive patients achieved a confirmed response, the trial would be deemed successful.

RESULTS

At data cut-off on 28th January 2021, we performed the final analysis of this trial. Of the 20 eligible and treated patients (19 of whom were evaluable for efficacy), with a median follow-up of 50 months, five were still on crizotinib treatment (4/12 ALK-positive and 1/8 ALK-negative patients). The updated objective response rate (ORR) was 66.7% (95% confidence interval [CI] 34.9-90.1%) in ALK-positive patients and 14.3% (95% CI 0.0-57.9%) in ALK-negative patients. In the ALK-positive and ALK-negative patients, the median progression-free survival was 18.0 months (95% CI 4.0-NE) and 14.3 months (95% CI 1.2-31.1), respectively; 3-year overall survival rates were 83.3% (95% CI 48.2-95.6) and 34.3% (95% CI 4.8-68.5). Safety results were consistent with previously reported data.

CONCLUSION

These updated results confirm previous findings that crizotinib is effective, with durable responses, in patients with locally advanced or metastatic ALK-positive IMT. With further follow-up after the original primary analysis, the ORR increased, as patients derived long-term benefit and some responses converted from stable disease to partial responses.

CLINICAL TRIAL NUMBER

EORTC 90101, NCT01524926.

Complicated course of biliary inflammatory myofibroblastic tumor mimicking hilar cholangiocarcinoma: A case report and literature review

BACKGROUND

The inflammatory myofibroblastic tumor (IMT) is a rare, idiopathic, usually benign, mass-forming disease with myofibroblastic proliferation and a varying amount of inflammatory cells. Although it can affect various organs, the biliary tract is a rare localization of primary IMT, clinically, endoscopically and radiologically imitating cholangiocarcinoma. The treatment options are based only on clinical practice experience.

CASE SUMMARY

A 70-year-old woman was referred to our center due to progressive fatigue, weight loss, abdominal pain, night sweats, and elevated liver enzymes. Magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography (ERCP) revealed proximal common hepatic duct and hilar biliary strictures extending bilaterally to lobular bile ducts. Although initial clinical, endoscopic and radiological signs were typical for hilar cholangiocarcinoma, histological examination showed no signs of malignancy. In total, 8 biopsies using different approaches were performed (several biopsies from dominant stricture during ERCP and direct cholangioscopy; ultrasound-guided liver biopsy; diagnostic laparoscopy with liver and lymph node biopsies). Histological examination revealed signs of IMT, and the final diagnosis of biliary IMT was stated. Although IMT is usually a benign disease, in our case, it was complicated. All pharmacological treatment measures were ineffective. The patient still needs permanent stenting, suffers from recurrent infections and mechanical jaundice. Despite that, the patient already survived 24 mo.

CONCLUSION

IMT presenting with hilar biliary strictures is a unique diagnostic and clinical challenge as it is indistinguishable from cholangiocarcinoma, and there are no evidence-based treatment options. Our goal is to increase the understanding of this rare disease and its possible course.

Inflammatory myofibroblastic tumor: molecular landscape, targeted therapeutics, and remaining challenges

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor of intermediate malignant potential that predominantly affects children, adolescents and young adults. IMT has a predilection for the lung, abdomen, pelvis, and retroperitoneum, however, can affect any part of the body. IMT is typically localized, and multifocal or metastatic disease is uncommon. Complete surgical resection is the treatment of choice when feasible. There is no established standard of care for unresectable and advanced IMT. Approximately half of IMTs harbor anaplastic lymphoma kinase (ALK) gene rearrangements, and fusions involving ROS1, PDGFRβ, RET and NTRK have also been described. Given the molecular landscape of IMT, management of these tumors has evolved to include tyrosine kinase inhibitors and novel targeted therapeutics. This review highlights the molecular characteristics, evolution of targeted therapies and the remaining challenges in the management of IMT.

Inflammatory Myofibroblastic Tumor of the Upper Airways Harboring a New TRAF3-ALK Fusion Transcript

Inflammatory myofibroblastic tumor (IMT) is a rare disease that mainly involves the lung and the abdomen with an intermediate clinical course but a recurrence rate between 15–30%. Radical surgery represents the gold standard of treatment, while chemotherapy and radiotherapy are considered for unresectable lesions. The identification of ALK translocations in IMT opened the option for the use of target therapies. Indeed, the ALK inhibitors have changed the treatment approach for aggressive lesions, improving the prognosis. Intraluminal upper-way IMT is extremely rare and represents a medical challenge. We reported an endotracheal IMT case presenting a previously unknown TRAF3-ALK fusion transcript.

Outstanding Response in a Patient With ROS1-Rearranged Inflammatory Myofibroblastic Tumor of Soft Tissues Treated With Crizotinib: Case Report

Inflammatory myofibroblastic tumor (IMT) is a very rare subtype of sarcoma, which frequently harbor chromosomal rearrangements, including anaplastic lymphoma kinase (ALK) rearrangements (almost 50% of the IMTs) and other kinase fusions such as ROS1. ROS1 fusions are present in about 10% of IMT, almost half of the ALK-negative IMT patients. Apart from radical surgery for resectable tumors, there is no standard-of-care therapy for advanced IMTs. Nonetheless, the use of tyrosine kinase inhibitors has shown promising efficacy in IMT patients with targetable genomic alterations. We report the case of a 24-year-old patient with chemotherapy-refractory metastatic IMT harboring ROS1 kinase fusion, who experienced a significant clinical and pathological response to crizotinib. This clinical case highlights the need to assess all patients with unresectable IMTs for chromosomal abnormalities and gene mutations and address them to targeted agents as well as clinical trials.

In Reply

This letter to the editor responds to questions about the results of the authors’ recently reported study of chemotherapy in inflammatory myofibroblastic tumors.

The 2020 WHO Classification of Soft Tissue Tumours: news and perspectives

Mesenchymal tumours represent one of the most challenging field of diagnostic pathology and refinement of classification schemes plays a key role in improving the quality of pathologic diagnosis and, as a consequence, of therapeutic options. The recent publication of the new WHO classification of Soft Tissue Tumours and Bone represents a major step toward improved standardization of diagnosis. Importantly, the 2020 WHO classification has been opened to expert clinicians that have further contributed to underline the key value of pathologic diagnosis as a rationale for proper treatment. Several relevant advances have been introduced. In the attempt to improve the prediction of clinical behaviour of solitary fibrous tumour, a risk assessment scheme has been implemented. NTRK-rearranged soft tissue tumours are now listed as an "emerging entity" also in consideration of the recent therapeutic developments in terms of NTRK inhibition. This decision has been source of a passionate debate regarding the definition of "tumour entity" as well as the consequences of a "pathology agnostic" approach to precision oncology. In consideration of their distinct clinicopathologic features, undifferentiated round cell sarcomas are now kept separate from Ewing sarcoma and subclassified, according to the underlying gene rearrangements, into three main subgroups (CIC, BCLR and not ETS fused sarcomas) Importantly, In order to avoid potential confusion, tumour entities such as gastrointestinal stroma tumours are addressed homogenously across the different WHO fascicles. Pathologic diagnosis represents the integration of morphologic, immunohistochemical and molecular characteristics and is a key element of clinical decision making. The WHO classification is as a key instrument to promote multidisciplinarity, stimulating pathologists, geneticists and clinicians to join efforts aimed to translate novel pathologic findings into more effective treatments.