Inflammatory Myofibroblastic Tumour: State of the Art

Podcast on Emerging Treatment Options for Pediatric Patients with ALK-Positive Anaplastic Large Cell Lymphoma and Inflammatory Myofibroblastic Tumors

Anaplastic large cell lymphoma (ALCL) and inflammatory myofibroblastic tumor (IMT) are rare cancers observed predominantly in children and young adults. ALCL accounts for 10-15% of all pediatric non-Hodgkin lymphomas and is commonly diagnosed at an advanced stage of disease. In children, 84-91% of cases of ALCL harbor an anaplastic lymphoma kinase (ALK) gene translocation. IMT is a rare mesenchymal neoplasm that also tends to occur in children and adolescents. Approximately 50-70% of IMT cases involve rearrangements in the ALK gene. A combination of chemotherapeutic drugs is typically used for children with ALK-positive ALCL, and the only known curative therapy for ALK-positive IMT is complete surgical resection. Crizotinib, a first-generation ALK inhibitor, was approved in the USA in 2021 for pediatric patients and young adults with relapsed or refractory ALK-positive ALCL; however, its safety and efficacy have not been established in older adults. In 2022, crizotinib was approved for adult and pediatric patients with unresectable, recurrent, or refractory ALK-positive IMT. This podcast provides an overview of ALK-positive ALCL and IMT. We discuss the current treatment landscape, the role of ALK tyrosine kinase inhibitors, and areas of future research.

Abdominal inflammatory myofibroblastic tumour: Clinicopathological and molecular analysis of 20 cases, highlighting potential therapeutic targets

AIMS

Inflammatory myofibroblastic tumour (IMT) is a rare mesenchymal neoplasm of intermediate malignant potential, occurring at any age and at multiple sites. Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is an aggressive subtype of IMT, typically involving the abdomen. Most IMTs harbour kinase gene fusions, especially involving ALK and ROS1, but 20-30% of IMTs show no detectable translocations. The aim of this study is to further delineate clinicopathological and molecular characteristics of abdominal IMT and discover potential new therapeutic targets.

METHODS AND RESULTS

In 20 IMTs, including four EIMS, RNA fusion analysis was performed, followed by multiplex DNA analysis if no ALK or ROS1 fusion was detected. Fourteen IMTs (70.0%) had an ALK translocation and the fusion partner was identified in 11, including a RRBP1::ALK fusion, not previously described in classical (non-EIMS) IMT. RANBP2::ALK fusion was demonstrated in all EIMS. One IMT had a ROS1 fusion. In all ALK/ROS1 translocation-negative IMTs mutations or fusions - as yet unreported in primary IMT - were found in genes related to the receptor tyrosine kinase (RTK)/PI3K/AKT pathway. Three of four patients with EIMS died of disease [mean survival 8 months (4-15 months)], whereas only one of 14 classical IMT patients succumbed to disease [mean follow-up time 52 months (2-204 months); P < 0.01].

CONCLUSION

This study shows the wide clinical spectrum of abdominal IMTs and affirms the poor prognosis of EIMS, raising discussion about its status as IMT subtype. Furthermore, the newly detected alterations of the RTK/PI3K/AKT pathway expand the molecular landscape of IMTs and provide potential therapeutic targets.

Endobronchial Inflammatory Myofibroblastic Tumour Masquerading as a Ruptured Hydatid Cyst

Inflammatory myofibroblastic tumours (IMTs) represent a rare group of neoplastic lesions characterized by a diverse clinical presentation. Endobronchial involvement is infrequently reported, and its manifestation mimicking the symptoms of a ruptured hydatid cyst adds an additional layer of complexity to the diagnostic challenge. This case report delves into an exceptional clinical scenario where an endobronchial IMT masqueraded as a ruptured hydatid cyst, initially confounding the diagnostic team. Through a detailed examination of the patient's clinical history, radiological imaging, bronchoscopy findings and subsequent histopathological analysis, we aim to contribute to the existing medical literature and shed light on the nuances encountered in accurately identifying and differentiating these two entities.

Clinical features, treatment strategies, and prognosis of epithelioid inflammatory myofibroblastic sarcoma in children: a multicenter experience

Background

Inflammatory myofibroblastic tumors (IMTs) are a spectrum of tumors that range in morphology and biological behavior from benign, intermediate, to apparently malignant and epithelioid inflammatory myofibroblastic sarcoma (EIMS) is one of the malignant subtypes. This study tried to provide experience and new ideas for treating this rare disease.

Methods

This study retrospectively analyzed and followed up 12 children with EIMS admitted to Beijing Children's Hospital, Baoding Children's Hospital, and Children's Hospital of Chongqing Medical University from August 2016 to May 2022.

Results

Of the 12 children, 7 were male and 5 were female, with a median age of 74.50 [interquartile range (IQR), 61.50-90.00] months. Of these patients, eight had a single lesion and four had multiple lesions. The maximum diameter of the single tumor foci was 19.30 cm, the full meridian of the multiple tumor foci target lesions was 32.67 cm, and the median maximum tumor size was 11.99 (IQR, 7.80-15.70) cm. The site of disease was the abdominopelvic cavity in eight cases, the thoracic cavity in two cases, the maxillofacial region in one case, and the larynx in one case. The clinical manifestations were predominantly elevated body temperature (n=8). There was one case of ROS1 fusion mutation and nine cases of ALK fusion mutation. Of the 12 children, 6 were biopsied at the initial diagnosis and 6 were surgically treated. Follow-up treatment included preoperative neoadjuvant chemotherapy (n=4), peritoneal thermal perfusion therapy (n=2), targeted therapy (n=3), postoperative chemotherapy (n=5), and radiotherapy (n=3). The follow-up time was 14.50 (IQR, 10.50-31.50) months, with eight cases of tumor-free survival, two cases of death, and two cases of loss of follow-up.

Conclusions

EIMS in children is extremely rare and clinically aggressive. The clinical presentation is nonspecific, and the initial diagnosis of the tumor is often large. Mutations in the ALK gene are common in EIMS. Surgery is the mainstay of EIMS treatment, and patients benefit from a multidisciplinary combination that includes targeted therapies, with long-term prognosis remaining subject to ongoing follow-up.

Anaplastic Lymphoma Kinase (ALK) in Posterior Cranial Fossa Tumors: A Scoping Review of Diagnostic, Prognostic, and Therapeutic Perspectives

Anaplastic Lymphoma Kinase (ALK) has been implicated in several human cancers. This review aims at mapping the available literature on the involvement of ALK in non-glial tumors localized in the posterior cranial fossa and at identifying diagnostic, prognostic, and therapeutic considerations. Following the PRISMA-ScR guidelines, studies were included if they investigated ALK's role in primary CNS, non-glial tumors located in the posterior cranial fossa. A total of 210 manuscripts were selected for full-text review and 16 finally met the inclusion criteria. The review included 55 cases of primary, intracranial neoplasms with ALK genetic alterations and/or protein expression, located in the posterior fossa, comprising of medulloblastoma, anaplastic large-cell lymphoma, histiocytosis, inflammatory myofibroblastic tumors, and intracranial myxoid mesenchymal tumors. ALK pathology was investigated via immunohistochemistry or genetic analysis. Several studies provided evidence for potential diagnostic and prognostic value for ALK assessment as well as therapeutic efficacy in its targeting. The available findings on ALK in posterior fossa tumors are limited. Nevertheless, previous findings suggest that ALK assessment is of diagnostic and prognostic value in medulloblastoma (WNT-activated). Interestingly, a substantial proportion of ALK-positive/altered CNS histiocytoses thus far identified have been localized in the posterior fossa. The therapeutic potential of ALK inhibition in histiocytosis warrants further investigation.

Unraveling the spectrum of inflammatory myofibroblastic tumors in the lung: A comprehensive case series highlighting endobronchial, pleural, and lung parenchymal tumors

Objectives

Diverse cases of inflammatory myofibroblastic tumors (IMTs) in the lung (pleural, endobronchial, and parenchymal) are presented while discussing the (preoperative) diagnostic challenges and treatment modalities. Other objectives include emphasizing the significance of gene rearrangements and highlighting the multidisciplinary approach in addressing IMTs.

Methods

Four cases of IMT in the lung are presented, including a young adolescent girl with an ETV6-neurotrophic tyrosine receptor kinase 3 (NTRK3) gene rearrangement, a 5-year-old boy with challenging preoperative diagnosis, and 2 middle-aged women with respectively pleural and endobronchial tumors with one peribronchial relapse.

Results

The cases demonstrate the diverse clinical presentations and diagnostic complexities associated with IMT in the lung. Surgical resection remains the primary treatment modality, with complete resection leading to a cure in most patients. Unfortunately, aggressive relapse can occur, as in our last case of an endobronchial tumor. Frozen section may confirm the presence of malignant cells perioperatively and impact further treatment. The presence of gene rearrangements, such as ETV6-NTRK3, suggests potential therapeutic implications.

Conclusions

Early detection and complete surgical removal of IMT are crucial for effective treatment. Identifying gene rearrangements such as ETV6-NTRK3 holds promise for targeted therapies. Diagnostic challenges, including the controversy of biopsies and preoperative evaluations, underscore the importance of a multidisciplinary approach. Anatomopathological recognition of IMT stays demanding. Close surveillance is necessary due to potential relapse, whereas frozen section perioperatively can help further treatment. This case series emphasizes the diagnostic challenges and therapeutic considerations for IMT in the lung.

Uniportal video-assisted thoracoscopic fissureless right upper lobe anterior segmentectomy for inflammatory myofibroblastic tumor: A case report

BACKGROUND

Inflammatory myofibroblastic tumors (IMTs) are exceptionally rare neoplasms with intermediate malignant potential. Surgery is the accepted treatment option, aiming for complete resection with clear margins.

CASE SUMMARY

A 39-year-old woman presented with a growing solitary pulmonary nodule measuring 2.0 cm in the right upper lobe (RUL) of the lung. The patient under-went a RUL anterior segmentectomy using uniportal video-assisted thoracoscopy. A preliminary tissue diagnosis indicated malignancy; however, it was later revised to an IMTs. Due to the absence of a minor fissure between the right upper and middle lobes, an alternative resection approach was necessary. Therefore, we utilized indocyanine green injection to aid in delineating the intersegmental plane. Following an uneventful recovery, the patient was discharged on the third postoperative day. Thereafter, annual chest tomography scans were scheduled to monitor for potential local recurrence.

CONCLUSION

This case underscores the challenges in diagnosing and managing IMTs, showing the importance of accurate pathologic assessments and tailored surgical strategies.

Gastric inflammatory myofibroblastic tumor presented with severe anemia and inflammation: a case report

BACKGROUND

Inflammatory myofibroblastic tumor (IMT) is a rare stromal tumor, often found in children and young adults, and most commonly occurs in the lungs. Surgical resection is considered the standard treatment for localized IMT, although only limited data exist. Gastric IMT in adults is extremely rare, and there are no established guidelines for its treatment.

CASE PRESENTATION

A 69-year-old male presented with persistent fatigue and weakness. Laboratory examination revealed severe anemia and inflammation. Upper gastrointestinal endoscopy at admission revealed a 40-mm type I softish tumor in the lesser curvature of the gastric body, without apparent hemorrhage. Repeated biopsies, including partial resection with snare, failed to give a definitive diagnosis. Computed tomography (CT) revealed a massive lesion at the gastric body, protruding into the gastric lumen, which was consistent with the gastric tumor. After admission, the patient developed anemia refractory to frequent blood transfusions despite the absence of apparent gastrointestinal bleeding. In addition, the patient had recurrent fevers of 38 °C or higher, and persistent high inflammatory levels. Fluorodeoxyglucose-positron emission tomography (FDG-PET) CT 1 month after the first visit exhibited an increased FDG uptake in the gastric tumor. In addition, this CT scan revealed a rapid increase in tumor size to 75 mm. It was suspected that the undiagnosed gastric tumor caused these serious clinical symptoms, and he underwent distal gastrectomy and cholecystectomy. The gross image of the tumor showed an 80-mm cauliflower-like shape with a gelatinous texture. The histopathological diagnosis was IMT. The postoperative course was uneventful, and the patient's symptoms subsided drastically, improving both anemia and systemic inflammation. The patient has shown no recurrence or relapse of the symptoms over one and a half years.

CONCLUSIONS

In this case, the tumor resection finally enabled the diagnosis of IMT and resolved the clinical symptoms. Despite its predominantly benign morphological nature, some cases of IMT present clinically adverse courses. Surgical treatment may lead to its final diagnosis and improvement of clinical symptoms.

Inflammatory myofibroblastic tumor of the submandibular gland Harboring MSN-ALK gene fusion: A case report and literature review

Inflammatory myofibroblastic tumors (IMTs) are rare lesions with distinct clinical, pathological, and molecular characteristics. IMTs typically arise in the abdominal soft tissues, including the mesentery, omentum, and retroperitoneum, followed by the lungs and mediastinum, and usually affect both children and young adults. Herein, we present a rare case of an IMT in the submandibular gland of a 47-year-old male patient. Microscopically, the tumor displayed an infiltrative growth pattern with diffuse glandular tissue destruction. Their backgrounds revealed characteristic spindles and inflammatory cells. Immunohistochemistry revealed positivity for anaplastic lymphoma kinase (ALK), smooth muscle actin, and calponin in neoplastic cells. The inflammatory cells and some neoplastic cells were positive for CD68. In contrast, negative staining for cytokeratin, desmin, and CD30 was observed. Furthermore, fluorescence in situ hybridization revealed ALK gene rearrangements, and next-generation sequencing detected a moesin (MSN)-ALK gene fusion. This case highlights a rare and unique occurrence of IMT originating from the submandibular gland, which exhibited an MSN-ALK gene fusion.

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.

Multiple Intrahepatic Inflammatory Myofibroblastic Tumor on 68 Ga-FAPI and 18 F-FDG PET/CT

ABSTRACT

A 31-year-old man with multiple intrahepatic inflammatory myofibroblastoma tumor was referred to nuclear medicine department to assess its malignant potential. Multiple lesions in the liver exhibited 68 Ga-FAPI uptake at different degrees. Instead, there was no abnormal 18 F-FDG activity in the other hepatic lesions under the normal liver background except for the puncture site. This case reflects tumor heterogeneity of the disease and shows the potential value of 68 Ga-FAPI PET/CT for the evaluation of hepatic inflammatory myofibroblastoma tumor.

[Receptor tyrosine kinase- fusions in paediatric spindle cell tumors]

Pediatric spindle cell tumors are rare and often difficult to diagnose due to a similar morphology and a non-specific immunohistochemical profile. Genetic characterization of these lesions has been constantly improving, which has led to the identification of new subgroups that were partly included in the WHO classification. Receptor tyrosine kinase fusions play a special role in these tumors and their verification has diagnostic relevance and can be an option for target-oriented therapies. In the case of pediatric spindle cell tumors, genetic fusions form especially with NTRK1‑3, ALK, RET, and ROS1. Overall, pediatric tumors with receptor tyrosine kinase fusions are predominantly low-grade tumors, which are often subdivided into the group of intermediate-malign tumors.

Case Report: Ensartinib for gastric epithelioid inflammatory myofibrosarcoma with STRN-ALK fusion

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is a highly aggressive malignant subtype of inflammatory myofibroblastoma (IMT) associated with poor prognosis. IMT can occur in various parts of the body, most frequently in the lungs, followed by the mesentery, omentum, retroperitoneum, and pelvis, among other areas; however, it is exceptionally rare in the stomach. Anaplastic lymphoma kinase (ALK) is a critical driver of lung cancer development and is currently the "gold standard" target for non-small cell lung cancer treatment. However, there are few reports on the use of ALK inhibitors for EIMS, necessitating further investigation. A male patient with postoperative inflammatory myofibroblastic sarcoma of the stomach received postoperative chemotherapy and had a stable outcome. However, a repeat CT scan performed 11 months later revealed disease progression. The patient later underwent immunohistochemistry testing that indicated ALK positivity, and next-generation sequencing revealed STRN-ALK fusion. Ensartinib 225 mg qd was administered as recommended, and the patient experienced only mild pruritus and no adverse effects such as rash. Eight months after CT follow-up, the patient's subseptal soft tissue nodules had decreased, and the outcome was assessed as a partial response. The findings of this case report introduce a novel strategy for treating ALK-positive EIMS that utilizes ensartinib, a drug with previously demonstrated success in the treatment of ALK-positive cancer.

Small biopsies in the head and neck: Bone and soft tissue

Bone and soft tissue lesions in the head and neck encompass not only a broad morphologic spectrum but also significant inherent clinicopathologic overlap. Epidemiology, radiology, and location - similar to the diagnostic assessment in other sites - are especially important considerations in the context of an established mesenchymal proliferation. Herein, the approach towards diagnosis is stratified by morphology (spindle, sarcomatoid, epithelioid, round cell), cellular lineage (fibroblastic, nerve sheath, rhabdomyogenic), and tumor grade (benign, low- to high-grade malignant) as the basis of further immunohistochemical or molecular investigation.

An update on selected cutaneous (myo) fibroblastic mesenchymal tumors

Cutaneous (myo)fibroblastic tumors constitute a group of tumors with overlapping clinicopathological features and variable biologic behavior. In the present review we focus on the histomorphology, immunohistochemical profile and molecular background of the following entities: dermatofibrosarcoma protuberans (DFSP), CD34-positive fibroblastic tumor (SCD34FT), myxoinflammatory sarcoma (MIFS), low-grade myofibroblastic sarcoma, solitary fibrous tumor and nodular fasciitis. Although some of these entities typically arise in deep-seated locations, they may occasionally present as cutaneous/superficial tumors and might be challenging to recognize. This review covers in depth the latest advances in molecular diagnostics and immunohistochemical markers that have significantly facilitated the correct classification and diagnosis of these neoplasms.

Increased 68 Ga-FAPI Activity in Hepatic Inflammatory Myofibroblastoma

ABSTRACT

Hepatic inflammatory myofibroblastoma is an uncommon borderline tumor. We present 68 Ga-FAPI PET/CT findings of hepatic inflammatory myofibroblastoma in a 58-year-old man. The rare hepatic inflammatory myofibroblastoma demonstrated intense tracer uptake on 68 Ga-FAPI PET/CT. This case demonstrates the potential value of 68 Ga-FAPI PET/CT for the evaluation of hepatic inflammatory myofibroblastoma.

Surgical treatment for lung metastasis of inflammatory myofibroblastic tumor of the lung: A case report

Inflammatory myofibroblastic tumor (IMT) is a rare disease that is considered an intermediate neoplasm, with the risk of recurrence and metastasis. Surgical treatment is the standard therapy for IMT, although there are only a few reports of surgery for lung metastasis of pulmonary IMT. We opine that surgical treatment might be effective not only for localized tumors, but also for cases of lung metastasis of 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.

Prevertebral Inflammatory Myofibroblastic Tumor Following COVID Vaccine Booster Dose

We report a case of a 30-year-old previously higid female presenting with dorsal pain and persistent fever after COVID-19 vaccine booster dose. CT and MR revealed a prevertebral heterogeneous and infiltrating mass, with spontaneous regression in control imaging which biopsy confirmed an inflammatory myofibroblastic tumor.