ALK1 and p80 expression and chromosomal rearrangements involving 2p23 in inflammatory myofibroblastic tumor

Two cases of inflammatory myofibroblastic tumor treated with targeted drugs: A case report

INTRODUCTION

Inflammatory myofibroblastic tumor (IMT) is a rare invasive soft tissue tumor. Many IMTs are positive for anaplastic lymphoma kinase (ALK) with ALK gene fusion; other gene mutations have also been reported, which indicates a key role for genetic testing and the development of target therapy to optimize treatment strategies.

PATIENT CONCERNS

We report 2 patients who obtained clinical benefits following targeted treatment with ensartinib.

DIAGNOSIS

The first patient was diagnosed as IMT, with TFG-ROS1 fusion gene mutation. The second patient was IMT harboring the ALK-STRN fusion gene mutation.

INTERVENTIONS

We performed gene testing for these 2 patients. According to the test result, both patients received ensartinib 225 mg QD as targeted therapy for a 30-day cycle.

OUTCOMES

The first patient achieved partial remission and maintained a stable state for 14.7 months. The second patient was treated for 10 months and reached complete remission after 5 months and is currently still benefiting from treatment. Treatment-related side effects were mild in both patients.

CONCLUSION

Our cases provided some new insights and approaches for the clinical diagnosis and treatment of IMT.

Anaplastic lymphoma kinase-positive pulmonary inflammatory myofibroblastic tumour: a case report

BACKGROUND

Pulmonary inflammatory myofibroblastic tumour (IMT) is a rare condition that usually presents in young individuals and is associated with anaplastic lymphoma kinase (ALK)-translocation.

CASE PRESENTATION

We report a case of an 18-year-old Caucasian man with ALK-translocated pulmonary IMT treated with multimodality therapy. The patient presented with breathlessness and was found to have a collapsed left lung. Further investigations revealed an ALK-translocated pulmonary IMT. This is usually treated with an ALK-inhibitor but patient declined after discussing potential side-effects and had repeated rigid bronchoscopic interventions for local disease control. Due to persistent local recurrence, patient received radical external beam radiotherapy (EBRT) with pulse steroids, and one year later started on Ibuprofen, a non-steroidal anti-inflammatory agent (NSAID). Following multimodality treatment, he developed a complete response. He remains treatment-free for the past seven years. Eleven years on from his diagnosis, he remains in remission with a ECOG performance status of zero.

CONCLUSIONS

Achieving long-term local control in pulmonary IMT can be challenging. Multimodality treatment is sometimes needed but the overall outlook remains good.

Inflammatory Myofibroblastic Tumour in Children: A Report of Two Cases and Review of Literature

ABSTRACT

Inflammatory myofibroblastic tumour in paediatric patients present with a diagnostic dilemma because of its clinical, radiological and histopathological features overlapping with other mesenchymal tumours common in this age. Because of its rarity, the exact features are still unclear. Here, we are reporting clinical, radiological and histopathological appearances of two such cases. In both cases, the exact diagnosis was confirmed only after immunohistochemistry. There is a need for further detailed study to exactly determine the natural course and prognosis of these tumours.

Reclassification of a spindle cell sarcoma after identification of a TFG-ROS1 fusion: A case demonstrating the clinical benefit of next-generation sequencing in sarcoma

BACKGROUND

Inflammatory myofibroblastic tumors (IMTs) are rare mesenchymal soft tissue sarcomas that often present diagnostic challenges due to their wide and varied morphology. A subset of IMTs have fusions involving ALK or ROS1. The role of next-generation sequencing (NGS) for classification of unselected sarcomas remains controversial.

METHODS AND RESULTS

We report a case of a metastatic sarcoma in a 34-year-old female originally diagnosed as an unclassified spindle cell sarcoma with myofibroblastic differentiation and later reclassified as IMT after NGS revealed a TFG-ROS1 rearrangement. Histologically, the neoplasm had spindle cell morphology with a lobulated to focally infiltrative growth pattern with scant inflammatory cell infiltrate. Immunohistochemistry demonstrated focal desmin and variable smooth muscle actin staining but was negative for SOX10, S100, and CD34. Fluorescence in situ hybridization was negative for USP6 or ALK gene rearrangements. NGS revealed a TFG-ROS1 rearrangement and the patient was treated with crizotinib with clinical benefit.

CONCLUSIONS

We discuss the role of NGS as well as its potential benefit in patients with unresectable, ALK-negative metastatic disease. Considering this case and previous literature, we support the use of NGS for patients requiring systemic treatment.

Functional Classification of Fusion Proteins in Sarcoma

Sarcomas comprise a heterogeneous group of malignant tumors of mesenchymal origin. More than 80 entities are associated with different mesenchymal lineages. Sarcomas with fibroblastic, muscle, bone, vascular, adipocytic, and other characteristics are distinguished. Nearly half of all entities contain specific chromosomal translocations that give rise to fusion proteins. These are mostly pathognomonic, and their detection by various molecular techniques supports histopathologic classification. Moreover, the fusion proteins act as oncogenic drivers, and their blockade represents a promising therapeutic approach. This review summarizes the current knowledge on fusion proteins in sarcoma. We categorize the different fusion proteins into functional classes, including kinases, epigenetic regulators, and transcription factors, and describe their mechanisms of action. Interestingly, while fusion proteins acting as transcription factors are found in all mesenchymal lineages, the others have a more restricted pattern. Most kinase-driven sarcomas belong to the fibroblastic/myofibroblastic lineage. Fusion proteins with an epigenetic function are mainly associated with sarcomas of unclear differentiation, suggesting that epigenetic dysregulation leads to a major change in cell identity. Comparison of mechanisms of action reveals recurrent functional modes, including antagonism of Polycomb activity by fusion proteins with epigenetic activity and recruitment of histone acetyltransferases by fusion transcription factors of the myogenic lineage. Finally, based on their biology, we describe potential approaches to block the activity of fusion proteins for therapeutic intervention. Overall, our work highlights differences as well as similarities in the biology of fusion proteins from different sarcomas and provides the basis for a functional classification.

A rare inflammatory myofibroblastic tumor appearing both inside and outside the heart

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is an uncommon cardiac tumor that primarily affects infants, children, and young adults. While complete surgical resection generally leads to a favorable prognosis, accurate diagnostic tests remain limited.

CASE PRESENTATION

We describe the case of a 26-year-old female who had a dual tumor inside and outside the heart and was misdiagnosed by echocardiography and MRI. We also review 71 cases of cardiac IMTs from the literature regarding their epidemiology, clinical presentation, and outcome.

CONCLUSION

Early detection of this rare disorder is essential for optimal surgical management.

A case of inflammatory myofibroblastic tumor harboring EML4-ALK fusion with a brain metastasis responding to alectinib

Metastatic inflammatory myofibroblastic tumor (IMT) is very rare and detailed reports on diagnosis and treatment are limited. Here, we report a case of metastatic IMT with ALK rearrangement. A 73-year-old woman was diagnosed with IMT involving a brain metastasis. Next generation sequencing (NGS) panel testing with Oncomine dx target test revealed that her tumor was positive for EML4-ALK. Treatment with alectinib was initiated, resulting in remarkable shrinkage of both the primary tumor and the brain metastasis. This report is the first to identify ALK rearrangement in IMT using a commercially available NGS panel testing, followed by treatment with alectinib. This case suggests that NGS panel testing may be useful in the diagnosis and treatment of patients with metastatic IMT.

Mesenchymal tumours of the pleura: review and update

Primary mesenchymal tumours of the pleura are uncommon and can be diagnostically challenging due to their overlapping histopathologic and immunophenotypic features. Herein we discuss selected mesenchymal tumours of the pleura, including solitary fibrous tumour, calcifying fibrous tumour, desmoid fibromatosis, synovial sarcoma, schwannoma, malignant peripheral nerve sheath tumour, inflammatory myofibroblastic tumour, follicular dendritic cell sarcoma, epithelioid hemangioendothelioma, and desmoplastic small round cell tumour. We review their clinicopathologic characteristics, along with an update on the relevant immunohistochemical and molecular features.

Individualized targeted treatment in a case of a rare TFG::ROS1 fusion positive inflammatory myofibroblastic tumor (IMT)

BACKGROUND

Inflammatory myofibroblastic tumor (IMTs) are rare mesenchymal neoplasms with slow growth. Resection is considered as therapeutic standard, with chemotherapy being insufficiently effective in advanced disease. ALK translocations are present in 50% of cases, ROS1 fusions (YWHAE::ROS1, TFG::ROS1) are extremely rare. Here, we present a case with TFG::ROS1 fusion and highlight the significance of molecular tumor boards (MTBs) in clinical precision oncology for post-last-line therapy.

CASE PRESENTATION

A 32-year-old woman presented with IMT diagnosed at age 27 for biopsy and treatment evaluation. Previous treatments included multiple resections and systemic therapy with vinblastine, cyclophosphamide, and methotrexate. A computed tomography scan showed extensive tumor infiltration of the psoas muscles and the posterior abdomen. Next generation sequencing revealed an actionable ROS1 fusion (TFG::ROS1) with breakpoints at exon 4/35 including the kinase domain and activating the RAS-pathway. TFG, the Trk-fused gene, exerts functions such as intracellular trafficking and exhibits high sequence homology between species. Based on single reports about efficacy of ROS1-targeting in ROS1 translocation positive IMTs the patient was started on crizotinib, an ATP-competitive small molecule c-MET, ALK and ROS1-inhibitor. With a follow-up of more than 9 months, the patient continues to show a profound response with major tumor regression, improved quality of life and no evidence for severe adverse events.

CONCLUSION

This case underscores the importance of the availability of modern molecular diagnostics and interdisciplinarity in precision oncology to identify rare, disease-defining genotypes that make an otherwise difficult-to-treat disease targetable.

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.

ALK fusions in the pan-cancer setting: another tumor-agnostic target?

Anaplastic lymphoma kinase (ALK) alterations (activating mutations, amplifications, and fusions/rearrangements) occur in ~3.3% of cancers. ALK fusions/rearrangements are discerned in >50% of inflammatory myofibroblastic tumors (IMTs) and anaplastic large cell lymphomas (ALCLs), but only in ~0.2% of other cancers outside of non-small cell lung cancer (NSCLC), a rate that may be below the viability threshold of even large-scale treatment trials. Five ALK inhibitors -alectinib, brigatinib, ceritinb, crizotinib, and lorlatinib-are FDA approved for ALK-aberrant NSCLCs, and crizotinib is also approved for ALK-aberrant IMTs and ALCL, including in children. Herein, we review the pharmacologic tractability of ALK alterations, focusing beyond NSCLC. Importantly, the hallmark of approved indications is the presence of ALK fusions/rearrangements, and response rates of ~50-85%. Moreover, there are numerous reports of ALK inhibitor activity in multiple solid and hematologic tumors (e.g., histiocytosis, leiomyosarcoma, lymphoma, myeloma, and colorectal, neuroendocrine, ovarian, pancreatic, renal, and thyroid cancer) bearing ALK fusions/rearrangements. Many reports used crizotinib or alectinib, but each of the approved ALK inhibitors have shown activity. ALK inhibitor activity is also seen in neuroblastoma, which bear ALK mutations (rather than fusions/rearrangements), but response rates are lower (~10-20%). Current data suggests that ALK inhibitors have tissue-agnostic activity in neoplasms bearing ALK fusions/rearrangements.

Inflammatory Myofibroblastic Tumor (IMT) of the Trachea Excised by Transtracheal Surgery: Case Report

This report describes an extremely rare case of a primary inflammatory myofibroblastic tumor of the trachea. The patient underwent surgical resection by a transtracheal approach and reconstruction with esophageal tracheoplasty. This case report highlights the rarity of such tumors and a minimally invasive and safe surgical technique for tumors around the central neck structures.

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.

Epithelioid inflammatory myofibroblastic sarcoma arising in the maxilla: first reported case in the jaws

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a rare variant of inflammatory myofibroblastic tumors located mostly in the intra-abdominal region. Herein, we present a case of a 32-year-old male with a lobulated growth in the right maxilla. Radiology revealed a solitary osteolytic lesion with an irregular margin, causing buccal and palatal cortex erosion. Histopathology revealed a tumor composed of spindle-shaped fascicles that blend into sheets of round to ovoid-shaped epithelioid cells, areas of myxoid changes, and necrosis. Tumor cells showed a moderate amount of eosinophilic cytoplasm, large vesicular nuclei with coarse chromatin, nuclear pleomorphism, and increased mitoses. Tumor cells were immunopositive for ALK-1, focal positivity for smooth muscle actin, panCK, epithelial membrane antigen, and immunonegativity for CD 30, desmin, CD34, and STAT6. P53 showed a wild-type staining pattern, and INI-1 expression was retained. The Ki-67 proliferative index was 22%. To the best of our knowledge, this is the first case of EIMS occurring in the maxilla.

Inflammatory myofibroblastic tumor of the urinary bladder with FN1‑ALK gene fusion: A case report

Inflammatory myofibroblastic tumors (IMTs), which are rare tumors, exhibit myofibroblastic differentiation, often with anaplastic lymphoma kinase (ALK) gene rearrangements. A subset of IMTs identified in the urinary tract have been shown to harbor a fibronectin 1 (FN1)-ALK gene fusion. In this case report, a case of an IMT with FN1-ALK fusion in the urinary bladder was presented, and its clinicopathological characteristics were reviewed. A 45-year-old female was referred to Chungbuk National University Hospital with gross hematuria. Cystoscopy revealed a solid mass in the bladder. The patient subsequently underwent transurethral resection of the lesion. The mass comprised stellate and spindled myofibroblastic cells that were arranged in loose fascicles, with a myxoid background and a mixed inflammatory infiltrate. Immunohistochemical analysis revealed that the tumor cells were positive for vimentin, cytokeratin AE1/AE3 and ALK, and focal-positive for desmin. Targeted next-generation sequencing was subsequently employed to identify the FN1-ALK fusion. To date, the patient has undergone outpatient follow-up for 18 months, with no signs of tumor recurrence. To conclude, in total, FN1 has been identified as an ALK fusion partner almost exclusively in cases of genitourinary IMTs [13 bladder IMTs (including the present case) and two uterine IMTs]. In the present case, the FN1-ALK fusion was found to involve ALK exon 19 and FN1 exon 23. By contrast, the majority of the other IMTs with an ALK fusion have involved ALK exon 20, whereas ALK fusion involving ALK exon 18 or 19 has been reported only in genitourinary IMTs. Therefore, the FN1-ALK fusion involving ALK exon 18 or 19 may be specific to a subset of IMTs arising in the urinary bladder.

Leiomyoma-like Morphology in Metastatic Uterine Inflammatory Myofibroblastic Tumors

Uterine inflammatory myofibroblastic tumors (IMTs) are rare mesenchymal neoplasms that frequently harbor ALK gene rearrangements and have a low risk of metastasis. We reported 3 of these tumors mimicking the appearance of leiomyoma in their recurrence. These patients were 34, 43, and 45 years old. Two uterine tumors demonstrated classic morphology, with combined myxoid, compact fascicular, and hyalinized patterns and spindled cells with bipolar cytoplasmic processes, moderate atypia, and lymphoplasmacytic inflammatory infiltrates. The third had a "leiomyoma-like" appearance, with fascicles of plump spindled cells and a sparse lymphoplasmacytic infiltrate. ALK immunohistochemistry was positive in all the tumors, and all demonstrated ALK rearrangements using fluorescence in situ hybridization (n = 2) and/or RNA sequencing (n = 2). Two classic IMTs recurred at 3 and 50 months in the lung and abdomen, respectively, and recurrent tumors had a "leiomyoma-like" appearance, with 0 and 1 mitosis per 10 high-power fields, no inflammation in 1, and a sparse lymphocytic infiltrate in the other. ALK was positive in both tumors; 1 with available tissue showed an IGFBP5::ALK fusion using RNA sequencing. The third patient, who had a "leiomyoma-like" uterine tumor, experienced multiple recurrences, first in the abdomen at 100 months showing a similar appearance. Subsequent recurrence at 105 months showed transmural invasion of the sigmoid colon and a similar microscopic appearance but with the addition of infiltrative borders, moderate cellularity, mild-to-moderate atypia, and 10 mitoses per 10 high-power fields. Both recurrences were positive for ALK, and RNA sequencing revealed the same ACTG2::ALK fusion transcript identified in the primary tumor. The patient was treated with crizotinib, resulting in prolonged clinical remission, with no evidence of disease at 168 months from the initial surgery. Although "leiomyoma-like" uterine IMTs have been recently described, to our knowledge, this is the first report of recurrence of these tumors and the first report of a "leiomyoma-like" appearance in the recurrences of conventional uterine IMTs. A low threshold for performing ALK immunohistochemistry on recurrent uterine tumors can identify patients who may benefit from tyrosine kinase inhibitors.

Inflammatory myofibroblastic tumor of the thyroid gland

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

Inflammatory Myofibroblastic Tumour of the Urinary Bladder in a Middle-Aged Man-A Case Report of an Unusual Localization of a Rare Tumour

Inflammatory myofibroblastic tumour (IMT) is a rare tumour with an intermediate biological behaviour. It usually occurs in children and adolescents, primarily in the abdomen or lungs. Histopathologically, IMT consists of spindle cells, i.e., myofibroblasts, and a variable inflammatory component. Localization in the urinary bladder is rare. We are presenting a rare case of IMT in the bladder in a middle-aged man treated by partial cystectomy. A 62-year-old man consulted a urologist because of haematuria and dysuric disturbances. A tumorous mass was detected by an ultrasound in the urinary bladder. CT urography described the tumorous mass at the dome of the urinary bladder measuring 2 × 5 cm. A smooth tumorous mass was cystoscopically observed at the dome of the urinary bladder. Transurethral resection of the bladder tumour was performed. Histopathological analysis of the specimen identified spindle cells with a mixed inflammatory infiltrate; immunohistochemical findings showed positivity for anaplastic lymphoma kinase (ALK), smooth muscle actin (SMA) and vimentin. A histopathological diagnosis of IMT was established. It was decided that the patient would undergo a partial cystectomy. A complete excision of the tumour from the dome of the urinary bladder with surrounding healthy tissue was performed. Histopathological and immunohistochemical findings of the sample confirmed the diagnosis of IMT, without the presence of the tumour at the surgical margins. The postoperative course went smoothly. IMT is a rare tumour in adults, especially localised in the urinary bladder. IMT of the urinary bladder is difficult to distinguish from urinary bladder malignancy both clinically and radiologically, as well as histopathologically. If the location and size of the tumour allow it, bladder-preserving surgeries such as partial cystectomy represent a reasonable modality of operative treatment.

Sinonasal Myxoma: A Distinct Entity or a Myxoid Variant of Desmoid Fibromatosis?

Sinonasal myxoma (SNM) is a rare benign mesenchymal tumor that arises in the sinonasal cavity or maxilla and almost exclusively affects young children. Currently, it is considered a specific entity, but its molecular characteristics have not been reported. Lesions diagnosed as SNM and odontogenic myxoma/fibromyxoma (OM/OFM) were identified from the participating institutions, and the clinicopathologic features were recorded. Immunohistochemistry for β-catenin was performed on all cases with available tissue. Next-generation sequencing (NGS) was performed on all SNM cases. Five patients with SNM were identified, including 3 boys and 2 girls with an age range of 20-36 months (mean: 26 months). The tumors were well-defined, centered in the maxillary sinus, surrounded by a rim of woven bone, and composed of a moderately cellular proliferation of spindle cells oriented in intersecting fascicles in a variably myxocollagenous stroma that contained extravasated erythrocytes. Histologically, the tumors resembled myxoid desmoid fibromatosis. Three tested cases showed nuclear expression of β-catenin. In 3 tumors, NGS revealed intragenic deletions of APC exons 5-6, 9 and 15, or 16, respectively, with concurrent loss of the other wild-type copy of APC, predicted to result in biallelic inactivation. The deletions were identical to those that occur in desmoid fibromatosis, and copy-number analysis raised the possibility that they were germline. In addition, one case showed possible deletion of APC exons 12-14, and another case exhibited a CTNNB1 p.S33C mutation. Ten patients with OM/OFM were identified, including 4 women and 6 men (mean age: 42 years). Seven tumors involved the mandible, and 3 the maxilla. Histologically, the tumors differed from SNM, and all cases lacked nuclear expression of β-catenin. These findings suggest that SNM represents a myxoid variant of desmoid fibromatosis that often arises in the maxilla. Because the APC alterations might be germline, genetic testing of the affected patients should be considered.

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.

Examining Stripes on a Herd of Zebras: Impact of Genomic Matching for Ultrarare Sarcomas in Phase 1 Clinical Trials (SAMBA 102)

PURPOSE

Recently, the Connective Tissue Oncology Society published consensus guidelines for recognizing ultrarare sarcomas (URS), defined as sarcomas with an incidence ≤1 per 1,000,000. We assessed the outcomes of 56 patients with soft tissue, and 21 with bone sarcomas, enrolled in Phase 1 trials.

EXPERIMENTAL DESIGN

In this Sarcoma-Matched Biomarker Analysis (SAMBA-102 study), we reviewed records from patients on Phase 1 trials at the University of Texas MD Anderson Cancer Center between January 2013 and June 2021.

RESULTS

Among 587 sarcomas, 106 (18.1%) were classified as URS. Fifty (47%) were male, and the median age was 44.3 years (range, 19-82). The most common subtypes were alveolar soft part sarcoma (ASPS), chordoma, dedifferentiated chondrosarcoma, and sclerosing epithelioid fibrosarcoma. Compared with common sarcomas, median OS was similar 16.1 months [95% confidence interval (CI), 13.6-17.5] versus 16.1 (95% CI, 8.2-24.0) in URS (P = 0.359). Objective response to treatment was higher in URS 13.2% (n = 14/106) compared with common sarcomas 6.9% (n = 33/481; P = 0.029). Median OS for those treated on matched trials was 27.3 months (95% CI, 1.9-52.7) compared with 13.4 months (95% CI, 6.3-20.6) for those not treated on matched trials (P = 0.291). Eight of 33 (24%) molecularly matched treatments resulted in an objective response, whereas 6 of 73 unmatched treatments (8.2%) resulted in an objective response (P = 0.024). Clinical benefit rate was 36.4% (12/33) in matched trials versus 26.0% (19/73) in unmatched trials (P = 0.279).

CONCLUSIONS

The results demonstrate the benefit of genomic selection in Phase 1 trials to help identify molecular subsets likely to benefit from targeted therapy.

Uterine inflammatory myofibroblastic tumor presented as abnormal uterine bleeding: Two cases report and literature review

RATIONALE

Inflammatory myofibroblastic tumor (IMT) is an extremely rare soft tissue neoplasm consisting of the proliferation of fibroblastic-myofibroblastic cells with inflammatory infiltrates. It is known to occur in many parts of the body and can generally present with benign or locally recurrent behavior. Anaplastic lymphoma kinase is a specific diagnostic marker for IMT, and approximately 50% of IMT patients have anaplastic lymphoma kinase gene rearrangements. Reports of the female genital tract are rare.

PATIENT CONCERNS

Two patients (a 32-year-old multigravida and a 22-year-old nullipara) visited our clinic because of abnormal uterine bleeding and a uterine mass.

DIAGNOSES

Histopathological examination, immunohistochemical markers, and fluorescence in situ hybridization confirmed the presence of a rare uterine IMT.

INTERVENTIONS

The masses were completely resected via hysteroscopy. The multigravida recurred rapidly in terms of symptoms and images, whereas the nullipara was complaint-free during the follow-up period. Finally, the multigravida underwent hysterectomy and bilateral salpingectomies.

OUTCOMES AND LESSONS

Uterine IMTs can be easily overlooked because of their extremely low incidence rate and insufficient awareness among clinicians; however, uterine IMTs need to be considered in the differential diagnosis of uterine masses. Possible differences in the biological behavior of IMT may exist in different individuals.

A Common Cell of Origin for Inflammatory Myofibroblastic Tumor and Lung Adenocarcinoma with ALK rearrangement

This case signifies the importance of obtaining tumor comprehensive genomic profiling (CGP) as it has utility in cancer type classification and helping in diagnosing recurrence/metastasis or separately occurring primary tumors. CGP can also help guiding treatment as in this case separately occurring Inflammatory Myofibroblastic Tumor had ALK fusion and responded to crizotinib. As treatment progresses, new biopsies should be obtained and CGP used to evaluate for appearance of any new genomic alterations, in order to guide further therapy.

S-100 Immuno-Positive Low Grade Myofibroblastic Sarcoma of Nasal Cavity: A Rare Case Presentation and Review of Literature

Introduction

Myofibroblastic neoplasms comprise a spectrum of benign/malignant neoplasms. Only low-grade malignant forms have been reproducibly characterized as a diagnostic entity in the WHO classification. Low grade myofibroblastic sarcoma (LGMFS) confined to the nasal cavity is extremely rare.

Objective

To review previously reported cases of nasal cavity LGMFS and provide a better insight regarding its clinical and immunohistochemical features.

Data synthesis

A review was performed involving two databases (PubMed and Google Scholar). Four cases of nasal cavity LGMFS were included. The lesion showed no gender or nasal-side predilection. All cases underwent wide excision. None showed distant metastasis while half recurred locally. Histologically, mitotic rate ranged from 1 to 3/10 high-power-field (HPF) and none exhibited spontaneous necrosis. Immuno-expression of calponin, smooth muscle actin (SMA) and vimentin were seen in either all four or three-fourth of cases. Diffuse S-100 expression was a unique finding in present case and not reported previously, that caused a diagnostic dilemma with schwannomas.

Conclusion

LGMFS of nasal cavity is extremely rare. A wide resection is the primary treatment of choice. Adjuvant therapies (chemotherapy or radiotherapy) are of uncertain significance. Distant metastasis is rather unusual. Calponin, SMA and vimentin are highly sensitive immuno-markers. Diffuse S-100 expression is a possible finding. Mitotic rate < 6/10 HPF and absence of spontaneous necrosis are characteristic indolent features differentiating from high grade lesions. Trifecta of clinical and morphological features plus immunohistological phenotype, are sufficient for a definitive diagnosis. Electron microscopy is the most definitive confirmation test, however, should be reserved only for equivocal/atypical immunostaining pattern.

A Large Inflammatory Myofibroblastic Tumor of the Urinary Bladder in a Parturient Treated by Partial Cystectomy: Case Report and Literature Review

Inflammatory myofibroblastic tumor (IMT) is a rare type of tumor composed mainly of fibroblastic and myofibroblastic spindle cells, with an inflammatory infiltrate of lymphocytes, plasma cells, and eosinophils. IMT may arise from different organs and sites, but it is infrequent to arise from the urinary bladder and usually manifests as hematuria. We report a case of a 24-year-old pregnant woman who presented to our hospital with gross hematuria. After further workup, we concluded that she had this extremely rare tumor, which was resected eventually with a partial cystectomy. Although the diagnosis of these kinds of tumors is usually made by anaplastic lymphoma kinase (ALK) using immunohistochemistry and detecting ALK gene translocation using fluorescence in situ hybridization (FISH), they were negative in our study; hence, we relied mainly on the morphological features of the tumor for the diagnosis.

Mesenteric inflammatory myofibroblastic tumor mimicking acute appendicitis: A case report

Introduction

An Inflammatory myofibroblastic tumor, a neoplasm of intermediate biological potential, of the small bowel mesentery, is a rare tumor, most commonly reported in but not confined to the pediatric age group.

Case presentation

This case report underlines a case of a (small bowel) mesentery IMT in an adult female presenting with recurrent symptoms similar to acute appendicitis.

Discussion

It can present with symptoms similar to acute appendicitis necessitating a high index of suspicion for its prompt diagnosis. Treatment primarily includes surgical resection with recent advances in targeted therapy with tyrosine kinase inhibitors showing promising results.

Conclusion

IMTs can present as clinical as well as histopathological mimickers of a variety of diseases especially in the abdomen. Prompt diagnosis requires both imaging and histopathological examination.

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Inflammatory myofibroblastic tumor is a neoplasm of intermediate biological potential of the small bowel mesentery.

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Prompt diagnosis requires both imaging and histopathological examination.

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Surgery still remains the main modality of treatment.

Infant biliary cirrhosis secondary to a biliary inflammatory myofibroblastic tumor: A case report and review of literature

BACKGROUND

A biliary inflammatory myofibroblastic tumor (IMT) is a rare type of mesenchymoma that, although it has a broad age spectrum, usually occurs in adults. Diagnosis is difficult because biliary IMTs often exhibit nonspecific clinical symptoms and imaging features, resulting in delayed or inappropriate treatment. Although most IMTs are benign, some show malignant properties such as infiltration, recurrence, and metastasis.

CASE SUMMARY

Here, we retrospectively describe a 10-month-old infant who was admitted to our hospital due to stubborn jaundice. The patient responded poorly to routine medical treatment and his clinical manifestations and laboratory tests lacked specificity, so we turned to repeated ultrasound scans and other imaging examinations. As both hepatosplenic ultrasonography and diffusion-weighted magnetic resonance imaging demonstrated a space-occupying lesion, an exploratory laparotomy was performed. The final diagnosis made over two mo after the disease onset was infant biliary cirrhosis caused by a biliary IMT, which partially infiltrated into the liver. This infant is the youngest case of biliary IMTs that has been reported till now. The patient underwent an incomplete resection of the mass and Kasai Portoenterostomy. However, because of cirrhosis, he also received a paternal liver transplant. Since some IMTs show malignant properties, we proceeded with a three-year of follow-up; however, no recurrence or metastasis has been noted.

CONCLUSION

Neoplastic disease such as IMTs should be considered when routine medical treatment of obstructive jaundice is not successful. Observation of dynamic imaging changes is helpful for diagnosis. Periodic follow-up is necessary for IMTs.

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.

Discovery of 2,4-diarylaminopyrimidine derivatives bearing dithiocarbamate moiety as novel ALK inhibitors

To overcome drug resistance caused by ALK kinase mutations especially G1202R, two series of novel 2,4-diarylaminopyrimidine derivatives bearing dithiocarbamate moiety were designed, synthesized and evaluated for their biological activities. Among all the target compounds, B10 efficiently inhibited the proliferation of ALK-positive Karpas299 and H2228 cells both with IC₅₀ values of 0.07 μM. In addition, B10 exhibited remarkable enzymatic inhibitory potency with IC₅₀ values of 4.59 nM, 2.07 nM and 5.95 nM toward ALK^WT, ALK^L1196M and ALK^G1202R, respectively. Furthermore, B10 induced apoptosis in H2228 cell and caused cell cycle arrest in G2/M phase. Ultimately, the binding modes of B10 with ALK^WT and ALK^G1202R were ideally established, which further confirmed the structural basis in accordance with the SARs analysis. These results indicated that B10 was a potent ALK inhibitor for ALK^G1202R mutation treatment and deserved for further investigation.

Mutations in ALK signaling pathways conferring resistance to ALK inhibitor treatment lead to collateral vulnerabilities in neuroblastoma cells

BACKGROUND

Development of resistance to targeted therapies has tempered initial optimism that precision oncology would improve poor outcomes for cancer patients. Resistance mechanisms, however, can also confer new resistance-specific vulnerabilities, termed collateral sensitivities. Here we investigated anaplastic lymphoma kinase (ALK) inhibitor resistance in neuroblastoma, a childhood cancer frequently affected by activating ALK alterations.

METHODS

Genome-wide forward genetic CRISPR-Cas9 based screens were performed to identify genes associated with ALK inhibitor resistance in neuroblastoma cell lines. Furthermore, the neuroblastoma cell line NBLW-R was rendered resistant by continuous exposure to ALK inhibitors. Genes identified to be associated with ALK inhibitor resistance were further investigated by generating suitable cell line models. In addition, tumor and liquid biopsy samples of four patients with ALK-mutated neuroblastomas before ALK inhibitor treatment and during tumor progression under treatment were genomically profiled.

RESULTS

Both genome-wide CRISPR-Cas9-based screens and preclinical spontaneous ALKi resistance models identified NF1 loss and activating NRASQ61K mutations to confer resistance to chemically diverse ALKi. Moreover, human neuroblastomas recurrently developed de novo loss of NF1 and activating RAS mutations after ALKi treatment, leading to therapy resistance. Pathway-specific perturbations confirmed that NF1 loss and activating RAS mutations lead to RAS-MAPK signaling even in the presence of ALKi. Intriguingly, NF1 loss rendered neuroblastoma cells hypersensitive to MEK inhibition.

CONCLUSIONS

Our results provide a clinically relevant mechanistic model of ALKi resistance in neuroblastoma and highlight new clinically actionable collateral sensitivities in resistant cells.

Infantile Inflammatory Myofibroblastic Tumor of Spleen

Background: Inflammatory myofibroblastic tumor (IMT) is a mesenchymal neoplasm with unknown etiology and recurrent potential. They are widely reported in children and young adults. Nearly 50% of inflammatory myofibroblastic tumor harbor rearrangement in anaplastic lymphoma kinase (ALK) gene with the majority expressing ALK protein. ALK-negative IMTs harbor alteration in ROS1 gene in a subset of cases. Few reports have shown association of IMT with Epstein-Barr virus (EBV). Case report: We report a case of IMT of the spleen in an 18-month-old infant presenting with abdominal distention and failure to thrive. Workup for ALK-1, ROS1, and EBV small-encoded RNA in-situ hybridization using immunohistochemistry was negative. Conclusions: IMT can arise in an infant spleen.

A unique case of inflammatory myofibroblastic tumor of the liver manifesting with biloma: A case report

Anaplastic lymphoma kinase (ALK)-negative hepatic inflammatory myofibroblastic tumors (IMTs) harboring the ETS variant transcription factor 6-neurotrophic receptor tyrosine kinase 3 (ETV6-NTRK3) fusion gene and manifesting with biloma are extremely rare, and their biological behavior is unclear. The present study reports the case of a 45-year-old female with ALK-negative IMT of the liver harboring the ETV6-NTRK3 fusion gene and manifesting with biloma. Computed tomography of the abdomen confirmed the lesions to be a low-density mass, measuring 11.2×8.5×10.5 cm, located in the left lobe of the liver, and a lower-density mass, measuring 8.5×6.1×5.9 cm, located in the interior of the tumor. As the suspicion of a malignancy remained high, surgical resection of the left hepatic lobe, including the tumor, was undertaken. Intraoperatively, a tumor (12×10×9 cm), with an unclear boundary, incomplete capsule and fish-like texture, was found in the left lateral lobe of the liver, and a biloma, measuring 8×6 cm, was identified inside the tumor. Pathological examination revealed spindle cell proliferation with infiltration of chronic inflammatory cells and mucinous degeneration. Immunohistochemical studies showed negativity for ALK, CD117, CD34, discovered on GIST-1, desmin, smooth muscle actin, S-100, CD21, pan-cytokeratin, epithelial membrane antigen, CD23 and CD35, but positivity for vimentin staining, and 5% Ki-67-positive cells. Fluorescence in situ hybridization studies assessing characteristic genetic rearrangements using ALK, RET, ROS1, MDM2, MGEA5 and ETV6 break-apart assays, revealed the presence of the ETV6-NTRK3 fusion oncogene and negativity for ALK, RET, ROS1, MDM2 and MGEA5. The patient was discharged 7 days post-operatively, without any adjuvant treatment. No recurrence of symptoms was noted at the 3-year follow-up. To the best of our knowledge, this is the first report of biloma in an ALK-negative IMT of the liver, which may increase our understanding of hepatic IMT.

Intraocular myofibroblastoma tumour of the ciliary body: a case report and literature review

Background

Inflammatory Myofibroblastoma Tumors (IMTs) are extremely tumour rare in the intraocular.

Case presentation

A ciliary body tumor was found under slit lamp biomicroscopy in a 55-year-old male first diagnosed with cataract. Then this patient underwent trans-sclera resection via partial lamellar sclerouvectomy and par plans vitrectomy to remove the mass. Hematoxylin and eosin (HE) staining and immunohistochemistry findings showed that the characteristics of the tumor were consistent with IMT.

Conclusions

We reported a rare case of intraocular IMT, which is confirmed by H&E staining, and IHC positive staining for Vimentin, Desmin and ALK, while negative staining for SMA, S-100, ki-67, CK, CD68, and calponin.

Anaplastic Lymphoma Kinase Positive Mesenteric Inflammatory Myofibroblastic Tumor in Adult Woman

Inflammatory myofibroblastic tumors (IMTs) are rare mesenchymal neoplasms containing spindle cells and inflammatory components that can be locally aggressive. They have unclear biological behavior and may recur after resection.

A 31-year-old woman presented with three months of cough, fatigue, weight loss, abdominal pain, anemia, and elevated inflammatory markers. CT showed a large well-circumscribed enhancing mass in the right colic mesentery. The patient underwent a laparoscopic right colectomy. Pathologic review showed fascicular spindle cells with admixed chronic inflammatory cells. Cells stained diffusely positive for SMA and anaplastic lymphoma kinase (ALK), diagnostic of an IMT. Post-operatively, the patient reported symptom resolution and had normalization of lab values. She remains disease-free at 20 months.

IMT is rare in adults, accounting for 0.7%-1.0% of lung tumors. Up to 30% of patients present with elevated inflammatory markers. On imaging, IMTs are soft tissue masses with variable enhancement and fibrosis, often suspected to be malignant neoplasms. Up to 80% of IMTs are driven by altered tyrosine kinase signaling and half of IMTs express ALK, which may be treated in unresectable/recurrent cases using ALK-inhibitors. IMT may recur in 10%-15% of patients. The roles of adjuvant treatments are unclear given the rarity and unpredictable biological behavior. Long-term follow-up with regular radiologic and laboratory surveillance is recommended given possible local recurrence. IMTs are best managed in a multidisciplinary setting given their unpredictable nature. Surgery is the mainstay of IMT treatment with long-term control expected in >80% of adult patients.

A novel WWTR1 :: AFF2 fusion in an intra‐abdominal soft tissue sarcoma with associated endometriosis

Application of molecular testing in clinical practice has led to significant advances in the classification of soft tissue sarcomas. Despite remarkable progress, there are still challenging cases that remain unclassified. In this study, we present an unusual spindle cell sarcoma arising in the abdominal cavity of a 37-year-old female. An extensive panel of immunostains was nonspecific for a line of differentiation and the tumor was subjected to targeted RNA sequencing for further classification. The findings showed a novel WWTR1::AFF2 fusion, which was further confirmed by break-apart FISH analysis for WWTR1 gene rearrangement. The tumor was attached to the wall of sigmoid colon and showed a highly cellular proliferation of plump spindle to epithelioid cells arranged in intersecting fascicles. Areas of extensive endometriosis were identified adjacent to the tumor. The immunoprofile was significant for reactivity with desmin, calponin, WT-1, ER, and PR, while negative for CD10, SMA, caldesmon, pan-keratin, ALK, CD117, and S100. The patient is alive and well after 11 months of follow-up. The exact histogenesis of this sarcoma remains unclear, however, the presence of adjacent endometriosis and coexpression of WT1/ER/PR raises the possibility of an unusual endometrioid stromal sarcoma, occurring outside the GYN tract. Additional cases are needed to establish the recurrent potential of this fusion event and to better define its pathogenesis and clinical behavior.

Primary Cutaneous Epithelioid Inflammatory Myofibroblastic Sarcoma Harboring RANBP2-ALK Fusion: Report of an Exceptional Case

ABSTRACT

Inflammatory myofibroblastic tumors are rare soft tissue neoplasms with an uncertain biological behavior, derived from fibroblastic and myofibroblastic cells. In rare cases, a peculiar epithelioid phenotypic variant of this tumor is encountered, named epithelioid inflammatory myofibroblastic sarcoma (EIMS). EIMS has overlapping features with inflammatory myofibroblastic tumor but has been correlated with a more aggressive clinical course, a characteristic nuclear membrane or perinuclear anaplastic lymphoma kinase (ALK) immunostaining pattern and a very specific RANBP2-ALK fusion. To date, EIMS has been reported almost exclusively in the abdominal and pelvic cavity, with the exception of some intrathoracic cases. Herein, we present the first case of primary cutaneous EIMS, confirmed by molecular analysis showing the diagnostic RANBP2-ALK fusion.

Aggressive Inflammatory Myofibroblastic Tumor of Distal Pancreas: A Diagnostic and Surgical Challenge

An inflammatory myofibroblastic tumor (IMT) is a rare soft tissue neoplasm of unknown etiology. It is a slow-growing tumor of borderline malignant potential. Distant metastases and recurrence after complete excision are rare. Establishing a preoperative diagnosis is difficult because of its nonspecific clinic-radiological features. Although the majority of cases have been reported in the lungs, it can affect any part of the body. The pancreatic inflammatory myofibroblastic tumor is very rare and only 26 cases have been reported in the medical literature. These tumors mostly arise from the head of the pancreas, whereas occurrence in the body or tail region is rather unusual. Here, we report a case of a 55-year-old male patient with a locally advanced inflammatory myofibroblastic tumor arising from the pancreatic tail. Complete excision of tumor required multi-visceral resection (distal pancreaticosplenectomy with jejunal and colonic segmental resection). The diagnosis of inflammatory myofibroblast tumor was made on the basis of histopathology and immunohistochemistry.

Durable Clinical Response to ALK Tyrosine Kinase Inhibitors in Epithelioid Inflammatory Myofibroblastic Sarcoma Harboring PRRC2B-ALK Rearrangement: A Case Report

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal neoplasm and patients with IMT tend to have a favorable outcome after complete surgical resection. However, some tumors of IMT cases have recurred and grown rapidly after successful surgery. Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a highly aggressive intra-abdominal IMT variant with epithelioid-to-round cell morphology. Currently, no standard therapy exists for recurrent or invasive IMTs and EIMS, but anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitors (TKIs) are recommended for those harboring ALK gene rearrangements. We herein report the first case of PRRC2B-ALK fusion associated IMTs with clinical and pathological manifestation matched the diagnosis criteria of EIMS and the durable clinical response of the sequential use of ALK TKIs (crizotinib, alectinib, ceritinib, and lorlatinib). A female patient with EIMS of the greater omentum was suffering from a rapid recurrence after cytoreductive surgery was done. Crizotinib was administered when PRRC2B-ALK fusion was detected, and partial response was achieved. The progression-free survival (PFS) of crizotinib was 5 months. Alectinib was administered based on the results of second next-generation sequencing (NGS) analysis, which identified the secondary mutation ALK R1192P. The best overall response of alectinib treatment was a partial response (PR) and the PFS was 5.5 months. Ceritinib was prescribed as third-line therapy after alectinib resistance with ALK L1196M mutation. PR was achieved and the PFS of ceritinib was 6 months. The patient was taking lorlatinib after ceritinib resistance and achieved a stable disease at 2 months with the PFS more than 5 months. The overall survival was more than two years as of the time of manuscript preparation. We describe an EIMS of greater omentum caused by PRRC2B-ALK fusion gene and showed durable clinical response to the sequential use of ALK TKIs.

Spitz nevus with EHBP1-ALK fusion and distinctive membranous localization of ALK

ALK rearrangements define a histopathologically distinctive but diverse subset of Spitz tumors characterized by fusiform to epithelioid melanocytes with frequent fascicular growth and ALK overexpression. Molecularly, these tumors are characterized by fusions between ALK and a variety of other genes, most commonly TPM3 and DCTN1. We describe an unusual case of a Spitz nevus occurring in a 13-year-old female that manifested ALK immunopositivity with cell membrane localization. The proliferation was polypoid and composed of elongated nests of epithelioid melanocytes with enlarged nuclei, prominent nucleoli, and abundant cytoplasm without significant atypia and lacking mitotic figures. The nevus exhibited strong and diffuse expression of p16. Targeted next-generation RNA sequencing revealed an in-frame EHBP1-ALK fusion, which has been reported only once in the literature. EHBP1 encodes an adaptor protein with plasma membrane targeting potential. Together, these findings suggest that the 5' ALK fusion partner in Spitz tumors may dictate the subcellular localization of the ALK chimeric oncoprotein. In summary, this case highlights a rare ALK fusion associated with a distinct immunohistochemical staining pattern and further expands the spectrum of ALK-rearranged melanocytic tumors. This article is protected by copyright. All rights reserved.

[Inflammatory Myofibroblastic Tumor Misdiagnosed as Intrahepatic Cholangiocarcinoma]

An inflammatory myofibroblastic tumor (IMT) is a rare tumor that is currently classified as an intermediate cancer according to the World Health Organization classification system. The pathophysiology of its occurrence is still unknown. Imaging tests, such as CT or MRI, can be helpful in diagnosis, but the final diagnosis is confirmed by a pathological examination through a biopsy and immunohistochemistry stain. The patient, in this case, presented an asymptomatic intrahepatic mass discovered incidentally on an imaging examination. Initially, intrahepatic cholangiocarcinoma was suspected, but she was finally diagnosed with IMT through a histological examination after a liver resection.

Molecular Targets for Novel Therapeutics in Pediatric Fusion-Positive Non-CNS Solid Tumors

Chromosomal fusions encoding novel molecular drivers have been identified in several solid tumors, and in recent years the identification of such pathogenetic events in tumor specimens has become clinically actionable. Pediatric sarcomas and other rare tumors that occur in children as well as adults are a group of heterogeneous tumors often with driver gene fusions for which some therapeutics have already been developed and approved, and others where there is opportunity for progress and innovation to impact on patient outcomes. We review the chromosomal rearrangements that represent oncogenic events in pediatric solid tumors outside of the central nervous system (CNS), such as Ewing Sarcoma, Rhabdomyosarcoma, Fibrolamellar Hepatocellular Carcinoma, and Renal Cell Carcinoma, among others. Various therapeutics such as CDK4/6, FGFR, ALK, VEGF, EGFR, PDGFR, NTRK, PARP, mTOR, BRAF, IGF1R, HDAC inhibitors are being explored among other novel therapeutic strategies such as ONC201/TIC10.

Assessment of ALK Fusions in Uncommon Inflammatory Myofibroblastic Tumors With ALK IHC Positivity but FISH-Equivocal Findings by Targeted RNA Sequencing

CONTEXT.—

Fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) are common methods to detect ALK status in inflammatory myofibroblastic tumors (IMTs). However, equivocal ALK FISH signals and inconsistency between FISH and IHC are occasionally observed.

OBJECTIVE.—

To study the inconsistency between FISH and IHC, and clarify ALK status in IMT by targeted RNA sequencing (RNAseq).

DESIGN.—

In this study, 12 consultation cases preliminarily diagnosed as uncommon IMTs with ALK IHC positivity but FISH negativity, plus 3 ALK-positive and 3 ALK-negative IMTs, were re-analyzed by IHC, FISH, and RNAseq.

RESULTS.—

As a result, 1 case with FUS-TFCP2 fusion was detected by RNAseq, which was previously misdiagnosed as IMT. In the other 11 uncommon IMTs, 90.9% (10 of 11) showed equivocal ALK FISH signals, and all were confirmed to harbor ALK fusion by RNAseq, except for 1 failure, suggesting that a low threshold for ALK FISH might be proposed in IMT. Furthermore, RNAseq also identified IGFBP5-ALK in 1 case with ALK IHC positivity but typical FISH negativity, suggesting the possibility of false negatives for ALK FISH. For the typical IMTs, ALK fusion was identified by RNAseq in all 3 ALK-positive IMTs as expected, and additionally FN1-ROS1 fusions were identified in 2 of 3 ALK-negative IMTs.

CONCLUSIONS.—

These findings indicated that RNAseq can simultaneously detect multiple gene fusions and provide fusion forms and breakpoints, which is of great value for differential diagnosis, especially for those uncommon IMTs with equivocal FISH findings, or inconsistency between IHC and FISH.

Mini-invasive endoscopic approach to tracheal inflammatory myofibroblastic tumor in a young woman: A case report

INTRODUCTION

Inflammatory myofibroblastic tumor (IMT) of the trachea is rare tumor mostly found in children and young adults.

CASE REPORT

We report a case of a 28 year-old woman who presented chronic isolated coughing. Chest CT scan showed a tracheal tumor. Rigid bronchoscopy allowed the complete removal of the tumor, and histology confirmed the diagnosis of IMT. 12 months follow-up found no recurrence.

DISCUSSION

IMT is a rare tumor exhibiting both benign and aggressive behaviour. The endoscopic approach of tracheal should be considered when there is a minimal tracheal wall invasion.

CONCLUSION

Through this case, we want to emphasise the role of rigid bronchoscopy in the complete removal of endotracheal IMT.

"How long does crizotinib work? a rare case of recurrent inflammatory myofibroblastic tumor"

Inflammatory myofibroblastic tumors (IMTs) are mesenchymal solid tumors, in which anaplastic lymphoma kinase (ALK) gene rearrangement might be detected. A 48-year-old female presented with IMT of lung, treated with surgery. After a 39-month disease-free survival metastatic recurrence was occurred involving soft tissues both infra- and supradiaphragmatic regions. The biopsies obtained from metastatic regions confirmed the recurrence with ALK rearrangement in immunohistochemistry. Initial partial response observed early in treatment course remained as a stable disease with crizotinib treatment. Although an excellent outcome with overall survival of 57 months was observed in our case, there is not enough information about survivals with crizotinib and the treatment options beyond progression. Therefore, every individual case has a unique value paving the way for more effective treatment.

ALK rearrangements in infantile fibrosarcoma-like spindle cell tumours of soft tissue and kidney

AIMS

Recurrent alterations in receptor tyrosine kinase (RTK) and downstream effectors are described in infantile fibrosarcoma (IFS)/cellular congenital mesoblastic nephroma (cCMN) and a subset of spindle cell sarcomas, provisionally designated 'NTRK-rearranged' spindle cell neoplasms. These two groups of tumours demonstrate overlapping morphologies and harbour alterations in NTRK1/2/3, RET, MET, ABL1, ROS1, RAF1 and BRAF, although their relationship is not fully elucidated. We describe herein a cohort of paediatric tumours with clinicopathological features not typical for inflammatory myofibroblastic tumour, but rather with similarities to cCMN/IFS harbouring ALK fusions.

METHODS AND RESULTS

Clinicopathological features were assessed and partner agnostic targeted RNA sequencing on clinically validated platforms were performed. Tumours occurred in patients aged from 2 to 10 years (median age 2 years) with a 2:2 male to female ratio and an average size of 8.4 cm. Two tumours arose in soft tissues and two in the kidney. Morphological features included spindle to ovoid cells arranged in long fascicles or haphazardly within a myxoid to collagenised stroma; a subset of cases had either dilated, ectatic vessels or focal perivascular hyalinosis. By immunohistochemistry, all cases tested showed cytoplasmic expression of anaplastic lymphoma kinase (ALK) and one case demonstrated co-expression of CD34 and S100.

CONCLUSIONS

This series of ALK-rearranged IFS-like tumours expands the spectrum of targetable kinases altered in these tumours and reinforces the potential overlap between IFS/cCMN-like tumours and the provisional entity of 'NTRK-rearranged' spindle cell neoplasms.

Ceritinib in paediatric patients with anaplastic lymphoma kinase-positive malignancies: an open-label, multicentre, phase 1, dose-escalation and dose-expansion study

BACKGROUND

Several paediatric malignancies, including anaplastic large cell lymphoma (ALCL), inflammatory myofibroblastic tumour (IMT), neuroblastoma, and rhabdomyosarcoma, harbour activation of anaplastic lymphoma kinase (ALK) through different mechanisms. Here, we report the safety, pharmacokinetics, and efficacy of ceritinib in paediatric patients with ALK-positive malignancies.

METHODS

This multicentre, open-label, phase 1 trial was done at 23 academic hospitals in ten countries. Children (aged ≥12 months to <18 years) diagnosed with locally advanced or metastatic ALK-positive malignancies that had progressed despite standard therapy, or for which no effective standard therapy were available, were eligible. ALK-positive malignancies were defined as those with ALK rearrangement, amplification, point mutation, or in the case of rhabdomyosarcoma, expression in the absence of any genetic alteration. Eligible patients had evaluable or measurable disease as defined by either Response Evaluation Criteria in Solid Tumours, version 1.1 for patients with non-haematological malignancies, International Neuroblastoma Response Criteria scan for patients with neuroblastoma, or International Working Group criteria for patients with lymphoma. Other eligibility criteria were Karnofsky performance status score of at least 60% for patients older than 12 years or Lansky score of at least 50% for patients aged 12 years or younger. This study included a dose-escalation part, followed by a dose-expansion part, in which all patients received treatment at the recommended dose for expansion (RDE) established in the dose-escalation part. Both parts of the study were done in fasted and fed states. In the dose-escalation part, patients were treated with once-daily ceritinib orally, with dose adjusted for body-surface area, rounded to the nearest multiple of the 50 mg dose strength. The starting dose in the fasted state was 300 mg/m² daily and for the fed state was 320 mg/m² daily. The primary objective of this study was to establish the maximum tolerated dose (ie, RDE) of ceritinib in the fasted and fed states. The RDE was established on the basis of the incidence of dose-limiting toxicities in patients who completed a minimum of 21 days of treatment with safety assessments and at least 75% drug exposure, or who discontinued treatment earlier because of dose-limiting toxicity. Overall response rate (defined as the proportion of patients with a best overall response of complete response or partial response) was a secondary endpoint. Activity and safety analyses were done in all patients who received at least one dose of ceritinib. This trial is registered with ClinicalTrials.gov (NCT01742286) and is completed.

FINDINGS

Between Aug 28, 2013, and Oct 17, 2017, 83 children with ALK-positive malignancies were enrolled to the dose-escalation (n=40) and dose-expansion (n=43) groups. The RDE of ceritinib was established as 510 mg/m² (fasted) and 500 mg/m² (fed). 55 patients (30 with neuroblastoma, ten with IMT, eight with ALCL, and seven with other tumour types) were treated with ceritinib at the RDE (13 patients at 510 mg/m² fasted and 42 patients at 500 mg/m² fed). The median follow-up was 33·3 months (IQR 24·8-39·3) for patients with neuroblastoma, 33·2 months (27·9-35·9) for those with IMT, 34·0 months (21·9-46·4) for those with ALCL, and 27·5 months (22·4-36·9) for patients with other tumour types. An overall response was recorded in six (20%; 95% CI 8-39) of 30 patients with neuroblastoma, seven (70%; 33-93) of ten patients with IMT, six (75%; 35-97) of eight patients with ALCL, and one (14%; <1-58) of seven patients with other tumours. The safety profile of ceritinib was consistent with that observed in adult patients. All patients had at least one adverse event. Grade 3 or 4 adverse events occurred in 67 (81%) of 83 patients and were mostly increases in aminotransferases (alanine aminotransferase increase in 38 [46%] patients and aspartate aminotransferase increase in 27 [33%] patients). At least one serious adverse event was reported in 40 (48%) of 83 patients and 31 (37%) of 83 patients had at least one grade 3 or 4 serious adverse event. 14 (17%) deaths occurred during the study, of which 12 were on-treatment deaths and two were after 30 days of the last dose. Of the 12 on-treatment deaths, ten were due to disease progression (neuroblastoma), one due to sepsis, and one due to intractable hypotension.

INTERPRETATION

Ceritinib 500 mg/m² once daily with food is the recommended dose for paediatric patients with ALK-positive malignancies. Ceritinib showed promising preliminary antitumour activity in patients with ALK-positive refractory or recurrent IMT or ALCL, and in a subset of patients with relapsed or refractory neuroblastoma, with a manageable safety profile. Our data support the notion that ALK inhibitors should be considered in therapeutic strategies for paediatric patients with malignancies with genetic ALK alterations.

FUNDING

Novartis Pharmaceutical Corporation.

Inflammatory Myofibroblastic Tumor 12 Years After Treatment for Synovial Sarcoma: A Case Report

Inflammatory myofibroblastic tumors (IMTs) are mesenchymal neoplasms most seen in the abdominopelvic region, lung, and retroperitoneum; and less commonly seen in virtually any other site. We report a case of two lower limb masses consistent with diagnosis of IMTs. This is a 39-year-old woman with a history of right lower extremity popliteal fossa synovial sarcoma diagnosed 12 years prior and treated with chemotherapy, surgery, and radiation. She presented with two new - one anterior and one posterior - right thigh masses. Biopsies of the lesions demonstrated low-grade inflammatory spindle cell lesions at both sites. Wide resection was performed for both masses and further characterization of the surgical specimens was most consistent with IMT. At follow-up, the patient is well with no signs of recurrence 19 and 7 months postoperative to the resection of the anterior and posterior thigh masses, respectively. This case represents the first reported IMTs occurring as late as 12 years after primary cancer treatment, and the first occurring after synovial sarcoma.

Molecular Alterations in Pediatric Fibroblastic/Myofibroblastic Tumors: An Appraisal of a Next Generation Sequencing Assay in a Retrospective Single Centre Study

BACKGROUND

Pediatric fibroblastic/myofibroblastic tumors (PFMTs) can be challenging to definitively classify. Large case series or diagnostic updates have not been recently published despite identification of molecular alterations that could improve diagnostic accuracy. Our review of the literature found that over two-thirds of the more than 30 types of PFMTs harbor recurrent molecular alterations. We performed an institutional review of PFMTs to highlight limitations of a predominantly morphological classification, and evaluated the utility of a next-generation sequencing assay to aid diagnosis.

METHODS

PFMTs identified over a period of 12 years were reviewed, categorized per the new WHO classification, and tested using the Oncomine Childhood Cancer Research Assay.

RESULTS

Eighty-seven specimens from 58 patients were reviewed; 50 were chosen for molecular analysis, 16 (32%) lacking definitive classification. We identified alterations, some novel, in 33% of assayed cases. Expected alterations were identified for most known diagnoses and mutations were identified in 6 of 16 tumors (38%) that were initially unclassified.

CONCLUSION

We confirmed a significant subset of PFMTs remain difficult to classify using current criteria, and that a combined DNA/RNA assay can identify alterations in many of these cases, improving diagnostic certainty and suggesting a clinical utility for challenging cases.