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.

Anaplastic lymphoma kinase1 positive inflammatory myofibroblastic tumor of the urinary bladder: A rare mesenchymal neoplasm with diagnostic and therapeutic implications

Inflammatory myofibroblastic tumors (IMTs) are rare mesenchymal neoplasms characterized by spindle-cell morphology with accompanying inflammatory infiltrates. Originally described in 1939, these tumors can arise in various anatomic locations, with the urinary bladder being a rare site of occurrence but the most common within the genitourinary tract. IMTs typically present as polypoid masses or firm submucosal nodules, often with painless hematuria in bladder cases. Histopathologically, IMTs are composed of myofibroblasts with myxoid stroma and mixed inflammatory cells, predominantly lymphocytes and plasma cells. Immunohistochemically, these tumors commonly express anaplastic lymphoma kinase1 (ALK1), vimentin, smooth muscle actin (SMA), and cytokeratin, with ALK1 serving as a crucial marker for diagnosis. This report details the case of a 31-year-old female presenting with hematuria, found to have a soft tissue mass in the urinary bladder (5.0 × 3.0 cm). Imaging revealed a well-defined lesion with vascularity. Histopathological examination confirmed an IMT, with immunohistochemistry showing diffuse ALK1 positivity, patchy SMA staining, and variable desmin expression, consistent with the diagnosis. IMTs are generally considered neoplasms of intermediate malignant potential. While metastasis is exceedingly rare in bladder IMTs, local recurrence has been reported, particularly in cases of incomplete surgical resection. Recent advances highlight the role of ALK inhibitors in managing unresectable cases, enabling partial cystectomy in select patients. This article underscores the importance of achieving complete surgical excision and highlights the role of ALK expression in diagnosis and differentiation from other spindle-cell neoplasms. Further studies are needed to elucidate the molecular and clinical factors influencing prognosis and to refine treatment strategies for IMTs.

Inflammatory Myofibroblastic Tumor in Bladder with Multiple Vesicocutaneous Fistula in Pediatric Patient: A Rare Case Report

Inflammatory myofibroblastic tumor (IMT) is a rare tumor that occurs at any age from childhood to late adulthood and may have a slight male predilection. A 7-year-old female presented with gross hematuria and a lump in the lower abdomen since 1 month prior to admission. The complaints were also accompanied by weight loss, abdominal pain and anemia. Ultrasound examination, Cystography, CT-Scan and MRI showed that mass in the bladder. Histopathology examination confirmed diagnosis for IMT, thus, radiology plays an important role in supporting histologic examination for diagnosis and evaluation of IMT.

Clinical features and prognostic factors of spinal fibroblastic/myofibroblastic tumors: a long-term, single-center, retrospective study

Background

Spinal fibroblastic and myofibroblastic tumors (FMTs) are extremely rare. Few studies have reported on the features and outcomes of this condition that affects the axial skeleton. We explored the clinical characteristics and factors affecting the prognosis of spinal FMTs.

Methods

We retroactively assessed the survival of 51 patients with spinal FMTs who underwent surgical and adjuvant treatments in our center between April 2006 and September 2018. Factors affecting disease-free survival (DFS) and overall survival (OS) were analyzed using the Kaplan–Meier method. Variables with p value ≤ 0.05 were subjected to multivariate analysis using the Cox proportional hazards regression model. A two-sided P value < 0.05 was considered statistically significant.

Results

The mean follow-up period was 50.8 ± 35.6 months (Range 4.2–172.6). Kaplan–Meier survival curves showed that the 5-year DFS was 10% (95% CI [31.09-42.56]) and the 5-year OS was 53% (95% CI [61.28–97.20]). Multivariate analysis showed that en bloc excision was associated with better DFS (HR 0.214, 0.011) and OS (HR 0.273, 0.043), radiotherapy negatively affected OS (HR 0.353, 0.033), and the recurrence and Ki-67 index <5% significantly affected DFS (HR 3.008, 0.008 and 2.754, 0.029).

Conclusions

Spinal FMTs are rare. Surgery is the treatment of choice and en bloc excision is strongly recommended to improve outcomes. Disease recurrence and the Ki-67 marker are correlated with the progression of these tumors.

Recurrent endobronchial inflammatory myofibroblastic tumors: Novel treatment options

Endobronchial inflammatory myofibroblastic tumors (IMTs) rarely occur in children younger than 10 years of age and have intermediate malignant potential. A 7-year-old girl initially presented with pneumonia. After failing outpatient treatment, she re-presented in status asthmaticus. Computed tomography showed a left mainstem endobronchial mass which was resected bronchoscopically. Pathology was consistent with IMT. Surveillance bronchoscopy identified a recurrence. Despite a left upper lobectomy, recurrence led to further treatment with celecoxib and argon plasma coagulation. Follow-up bronchoscopy revealed complete resolution. She remains disease and symptom-free at her six-year follow-up.

Inflammatory myofibroblastic tumor: The experience of the European pediatric Soft Tissue Sarcoma Study Group (EpSSG)

INTRODUCTION

We report the clinical findings and results of treatment in the cohort of patients with inflammatory myofibroblastic tumor (IMT) managed according to the European pediatric Soft Tissue Sarcoma Study Group (EpSSG) protocol from 2005 to 2016.

METHODS

Patients (<25 years old) with IMT from 9 countries were prospectively registered via a web-based system. Their histology was reviewed by a national/international pathology panel. Immunohistochemistry for ALK assessment was mandatory. No adjuvant therapy was suggested for initially resected tumors. No specific systemic therapy was recommended for cases of unresectable disease.

RESULTS

Among 80 cases of IMT registered, 20 were excluded because pathology review led to a revised diagnosis. Of the remaining 60 patients (median age 9.5 years), 59 had localized, and 1 had multifocal/metastatic disease. The lung was the primary site in 14 cases. IMT developed as a second tumor in 2 cases. Forty cases were ALK-positive, and 20 were ALK-negative. Five-year event-free survival (EFS) and overall survival (OS) were 82.9% and 98.1%, respectively. No clinical variables correlated statistically with the outcome: survival was the same for ALK-positive and ALK-negative cases. The overall response to systemic therapy was 64%: 8/10 cases responded to vinblastine-methotrexate chemotherapy, and 5/5 to ALK-inhibitors.

CONCLUSIONS

This study demonstrated a good overall prognosis for IMT, even for initially unresectable disease and in ALK-negative cases. Chemotherapy is still a valid option for advanced disease. Larger studies involving both pediatric and adult patients are needed to clarify the role of ALK inhibitors.

PDGRFB mutation-associated myofibromatosis: Response to targeted therapy with imatinib

Heterozygous activating mutations in platelet-derived growth factor receptor B (PDGFRB) have been recently identified as a cause of autosomal-dominant infantile myofibromatosis. We describe a 36-year-old man with PDGFRB c.1681C>T (p.R561C) mutation. Upon progressive disease, the patient received treatment with imatinib and showed a remarkable response with remission of multiple lesions after 12 months. This is the first report of an adult patient with PDGFRB c.1681C>T mutation treated with imatinib.

TRK Fusion Cancers in Children: A Clinical Review and Recommendations for Screening

Chromosomal translocations involving the NTRK1, NTRK2, and NTRK3 genes (TRK fusions), which encode the neurotrophin tyrosine kinase receptors TRKA, TRKB, and TRKC, can result in constitutive activation and aberrant expression of TRK kinase. Certain cancers almost universally harbor TRK fusions, including infantile fibrosarcoma, cellular congenital mesoblastic nephroma, secretory breast cancer, and mammary analog secretory carcinoma of the salivary gland. TRK fusions have also been identified at lower frequencies across a broad range of other pediatric cancers, including undifferentiated sarcomas, gliomas, papillary thyroid cancers, spitzoid neoplasms, inflammatory myofibroblastic tumors, and acute leukemias. Here we review the prevalence and diseases associated with TRK fusions and methods of detection of these fusions in light of the recent development of selective TRK inhibitors, such as larotrectinib, which demonstrated a 75% response rate across children and adults with TRK fusion cancers. We provide recommendations for screening pediatric tumors for the presence of TRK fusions, including the use of immunohistochemistry or fluorescence in situ hybridization for patients with tumors likely to harbor TRK fusions. Further, we recommend next-generation sequencing for tumors that have a relatively low prevalence of TRK fusions, both to identify patients who may benefit from TRK inhibition and to identify other targetable oncogenic drivers that exist in the same tumor types.

Case report: rapid and durable response to PDGFR targeted therapy in a child with refractory multiple infantile myofibromatosis and a heterozygous germline mutation of the PDGFRB gene

Background

Infantile myofibromatosis belongs to a family of soft tissue tumors. The majority of these tumors have benign behavior but resistant and malignant courses are known, namely in tumors with visceral involvement. The standard of care is surgical resection. Observations suggest that low dose chemotherapy is beneficial. The treatment of resistant or relapsed patients with multifocal disease remains challenging. Patients that harbor an actionable mutation in the kinase domain are potential subjects for targeted tyrosine kinase inhibitor therapy.

Case presentation

An infant boy with inborn generalized infantile myofibromatosis that included bone, intracranial, soft tissue and visceral involvement was treated according to recent recommendations with low dose chemotherapy. The presence of a partial but temporary response led to a second line of treatment with six cycles of chemotherapy, which achieved a partial response again but was followed by severe toxicity. The generalized progression of the disease was observed later. Genetic analyses were performed and revealed a PDGFRB gene c.1681C>A missense heterozygous germline mutation, high PDGFRβ phosphokinase activity within the tumor and the heterozygous germline Slavic Nijmegen breakage syndrome 657del5 mutation in the NBN gene. Targeted treatment with sunitinib, the PDGFRβ inhibitor, plus low dose vinblastine led to an unexpected and durable response without toxicities or limitations to daily life activities. The presence of the Slavic NBN gene mutation limited standard chemotherapy dosing due to severe toxicities. Sister of the patient suffred from skull base tumor with same genotype and histology. The same targeted therapy led to similar quick and durable response.

Conclusion

Progressive and resistant incurable infantile myofibromatosis can be successfully treated with the new approach described herein. Detailed insights into the biology of the patient’s tumor and genome are necessary to understand the mechanisms of activity of less toxic and effective drugs except for up to date population-based chemotherapy regimens.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-017-3115-x) contains supplementary material, which is available to authorized users.