Inflammatory myofibroblastic tumor from molecular diagnostics to current treatment.

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

Inflammatory myofibroblastic tumor in the urinary bladder in a dog.

An 8-year-old castrated male Maltese dog was presented with a urinary bladder mass, urolithiasis, and hematuria. A solitary, pedunculated, intraluminal mass on the caudodorsal wall was identified with extensive irregular bladder wall thickening, and the mass was surgically removed. Postoperative histopathology demonstrated a submucosal lesion comprising spindle cells with marked inflammatory cell infiltration, without malignant changes. Immunohistochemical staining revealed vimentin and desmin positivity in the mass. An inflammatory myofibroblastic tumor (IMT) was definitively diagnosed. No recurrence was observed during a 43-month follow-up period. Although IMTs are rare in dogs, they should be considered a differential diagnosis for mass-like urinary bladder lesions accompanying a chronic inflammatory disease process. Key clinical message: Canine IMT should be included in the differential diagnoses of bladder masses, especially when dogs exhibit chronic irritation and inflammation.

Tumeur myofibroblastique inflammatoire de la vessie chez un chienUn chien maltais mâle castré de 8 ans a été présenté avec une masse à la vessie, une lithiase urinaire et une hématurie. Une masse intraluminale pédonculée solitaire sur la paroi caudodorsale a été identifiée avec un épaississement important et irrégulier de la paroi vésicale, et la masse a été retirée chirurgicalement. L'histopathologie postopératoire a mis en évidence une lésion à la sous-muqueuse comprenant des cellules fusiformes avec une infiltration cellulaire inflammatoire marquée, sans modification maligne. La coloration immunohistochimique a révélé une positivité à la vimentine et à la desmine dans la masse. Une tumeur myofibroblastique inflammatoire (IMT) a été définitivement diagnostiquée. Aucune récidive n'a été observée au cours d'une période de suivi de 43 mois. Bien que les IMT soient rares chez le chien, ils doivent être considérés comme un diagnostic différentiel des lésions de la vessie de type masse accompagnant un processus de maladie inflammatoire chronique.Message clinique clé:L'IMT canine doit être incluse dans les diagnostics différentiels des masses vésicales, en particulier lorsque les chiens présentent une irritation et une inflammation chroniques.(Traduit par Dr Serge Messier).

Inflammatory myofibroblastic tumours of the liver - a systematic review.

BACKGROUND: Hepatic inflammatory myofibroblastic tumours (HIMTs) are rare and poorly described in the literature. Most publications are single patient case reports and lack detailed reporting on characteristics, management, and outcomes. This systematic review aimed to assess the demography, clinical presentation, typical imaging features, histopathology, treatment, and outcomes of patients presenting with HIMTs. METHODS: A systematic literature search was performed in MEDLINE (PubMed), EMBASE (Scopus), JSTOR, Cochrane CENTRAL (Cochrane Library), and the databases included in the Web of Science for studies published between 1940 and 2023 on HIMTs, including its reported synonyms. Case series or cohort studies that reported on the management and outcomes of at least four patients with histologically confirmed HIMTs were included in the analysis. RESULTS: After screening 4553 publications, 22 articles including a total of 440 patients with confirmed HIMTs were eligible for inclusion. The average age was 53.4 years (range 42.0-65.0) with a male to female ratio of 1.7:1. Abdominal pain, discomfort, fever, and loss of weight were the most common presenting symptoms. Surgical resection is the standard of care for HIMTs and is associated with low mortality of 3.4% and low disease recurrence. CONCLUSION: HIMT is a disease more often affecting middle-aged males. The lesions are typically solitary with low recurrence after treatment. The relative roles of surgical versus medical treatment remain unclear. Differences in clinical presentation, histopathology, and treatment of HIMTs compared to inflammatory myofibroblastic tumour (IMT) at extrahepatic sites could challenge the current view of IMT as a single pathological entity.

Treatment and outcomes in pediatric inflammatory myofibroblastic tumors - A systematic review of published studies.

Inflammatory myofibroblastic tumor (IMT) is a soft tissue neoplasm which can be locally invasive, recur, or in rare cases metastasize. Often originating from the abdomen or thorax, IMT most commonly affects children and young adults. Due to its rarity comprehensive reports detailing clinical management and outcome(s) are sparse and often based on limited index case numbers. This study systematically analyzes outcome metrics of pediatric IMT and identifies risk factors for mortality. Medline/Embase databases were searched in accordance with PRISMA guidelines. Final analysis included 57 studies with 673 IMT patients (355 males, 53 %). Individual patient data was available for 405 cases with a median follow-up period of 36 months. Tumor sites included abdomen/pelvis (n = 233, 58 %), thorax (n = 125, 31 %), head/neck (n = 34, 8 %), and extremities (n = 13, 3 %). Surgical tumor resection was the mainstay of treatment, while only 20 patients (5 %) were treated non-operatively. Recurrence(s) were reported in 80 patients (20 %) with 34 (12 %) requiring reoperation. Positive tumor margins were a significant risk factor for tumor recurrence (p < 0.0001). Chemo/radiotherapy was reported in 98 patients (25 %). Most patients (94 %) survived; 81 % (n = 237) with no evidence of recurrent disease, 14 % (n = 41) were alive with disease, and 25 (6 %) died of disease. Positive margins at primary operation, and metastatic disease were associated with mortality (p < 0.0001 for both). IMT is a rare tumor with favorable outcome for the majority of patients. Whilst most patients will present with benign tumors, complete surgical resection (R0) is crucial, as positive surgical margins are a significant risk factor for tumor recurrence and mortality.

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.

Uterine Inflammatory Myofibroblastic Tumors: p16 as a Surrogate for CDKN2A Deletion and Predictor of Aggressive Behavior.

Uterine inflammatory myofibroblastic tumors (IMTs) are rare mesenchymal neoplasms of uncertain malignant potential. Aside from the recently described risk stratification score, which has not been validated by other studies, and rare reports of aberrant p16 expression in malignant tumors, there are no criteria to reliably predict behavior. Herein, we evaluated the clinicopathologic features and p16 expression patterns in 30 IMTs, with genomic profiling performed in a subset (13 malignant, 3 benign). Fifteen patients had malignant IMTs, defined by extrauterine disease at diagnosis (n=5) or recurrence (n=10; median: 24 mo). Patients ranged from 8 to 65 (median: 51) years and tumors from 6 to 22 (median: 12.5) cm. In primary tumors (n=13), infiltrative borders were noted in 10, moderate/severe cytologic atypia in 9, tumor cell necrosis in 7, and lymphovascular invasion in 6, while mitoses ranged from 0 to 21 (median: 7) per 10 high-power fields. In contrast, 15 patients with benign IMTs ranged from 28 to 65 (median: 44) years, with follow-up of 18 to 114 (median: 41) months. Tumors ranged from 1.9 to 8.5 (median: 5.5) cm, 2 demonstrated infiltrative borders, and 1 had moderate cytologic atypia. No other high-risk histologic features were observed. Application of the previously described clinicopathologic risk stratification score in all primary IMTs with complete data (n=18) classified 8 as high-risk (all malignant), 8 as intermediate-risk (3 malignant, 5 benign), and 2 as low-risk (benign). p16 was aberrant in all malignant IMTs, with <1% expression noted in 10, overexpression (>90%) in 4, and subclonal loss in 1; all benign tumors had patchy staining (20% to 80%; median 50%). Molecular analysis detected CDKN2A deletions in 8 of 9 tumors with <1% p16 expression, while the other harbored a TERT promoter mutation. TERT promoter mutations were also identified in 2 of 3 IMTs with p16 overexpression. Neither of these alterations was detected in the 3 sequenced benign IMTs. Thus, we recommend performing p16 on all uterine IMTs, which, combined with the risk stratification score, is a promising and cost-effective tool for predicting CDKN2A status and outcome in these patients. It may be particularly useful for tumors with incomplete information for risk stratification (ie, morcellated tumors) and for further stratifying intermediate-risk IMTs when sequencing is unavailable.

Advances in uterine inflammatory myofibroblastic tumours: Diagnostic challenges and risk stratification.

The current understanding of inflammatory myofibroblastic tumours (IMTs) of the gynaecological tract has recently been enhanced by their increased recognition. This increase is largely due to greater accessibility to RNA-based molecular assays used to identify their defining ALK rearrangements. This review summarises the clinical characteristics, morphological spectrum, immunohistochemical profile and molecular underpinnings of uterine IMT. Additionally, this review discusses practical diagnostic considerations including overlap between uterine IMT and smooth muscle tumours as well as pregnancy-associated uterine IMT. Finally, we highlight recent literature demonstrating the potential for aggressive behaviour in uterine IMT, including a novel risk stratification model for identifying high-risk IMT.

Unresectable infantile myofibroma discovered in utero.

The authors present a case of a proliferative nodule located beneath an infant's lower lip that was initially discovered on prenatal ultrasound and fetal magnetic resonance imaging (MRI). Biopsy revealed a smooth muscle actin-positive spindled cell proliferation with hemangiopericytoma-like vessels consistent with infantile myofibromatosis (IM). Since the location prevented surgical management, the clinicians opted to observe the lesion. Ultimately, the lesion fully regressed on its own confirming conservative management is an option for isolated IM.

[Intranodal palisaded myofibroblastome: A rare cause of inguinal lymphadenopathy]. / Le myofibroblastome palissadique intraganglionnaire : une cause rare d'adénopathie inguinale.

INTRODUCTION: Lymphadenopathies are a major cause of consultation in internal medicine, with various causes of diagnosis. Unexplained persistent lymphadenopathy must be biopsied to rule out malignant tumor. CASE REPORT: We report the case of a 53-year-old man, with inguinal lymphadenopathy evolving for more than one year. The patient had no associated symptoms and his blood tests were unremarkable. Due to the progression of the adenopathy and its hypermetabolism on PET-CT, an excisional biopsy was performed. Histological analysis revealed an intranodal proliferation of spindle cells with a palisading pattern. ß-catenine and smooth muscle actin labelling were positive, leading to the diagnosis of intranodal palisaded myofibroblastoma, a benign tumour. CONCLUSION: Intranodal palisaded myofibroblastoma is a rare benign cause of adenopathy, with often inguinal lymph node localization and slow growth and without risk of recurrence after surgical removal.

Vulval superficial myofibroblastoma with lymphocytic and eosinophilic infiltrate.

We present the case of a vulval superficial myofibroblastoma with a lymphocytic and eosinophilic rim in a woman in her late 20s. The tumour presented in pregnancy as a cystic lesion with pain and increasing size. While the histopathology of superficial myofibroblastomas has been well defined in the literature, to our knowledge, there has been no documentation of the presence of an inflammatory infiltrate of lymphocytes and eosinophils surrounding and within the tumour. This may potentially act as a diagnostic or prognostic reference.

CTNNB1 somatic mutations drive Wnt pathway activation in a case of incidental intranodal palisaded myofibroblastoma.

Intranodal palisaded myofibroblastoma (IPM) is a rare stroma-derived spindle-cell neoplasm of the lymph node with myofibroblastic differentiation and CTNNB1 (ß-catenin gene) somatic mutations. We present a case of IPM found incidentally in the staging of lung adenocarcinoma. We describe the major histopathological and phenotypic features, including a palisaded bland spindle cell proliferation with myofibroblastic differentiation and Wnt pathway activation by immunohistochemistry, including ß-catenin expression. Production of osteoid-like collagen directly from tumor cells was observed. We confirmed p.Gly34Arg CTNNB1 mutation by direct sequencing. We also reviewed the literature for similar cases.

[Mammary myofibroblastoma: a clinicopathological analysis of fifteen cases].

Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of breast myofibroblastoma. Methods: The clinicopathological data and prognostic information of 15 patients with breast myofibroblastoma diagnosed at the Department of Pathology of the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China from 2014 to 2022 were collected. Their clinical characteristics, histological subtypes, immunophenotypes and molecular characteristics were analyzed. Results: There were 12 female and 3 male patients, ranging in age from 18 to 78 years, with a median and average age of 52 years. There were 6 cases in the left breast and 9 cases in the right breast, including 12 cases in outer upper quadrant, 2 cases in inner upper quadrant and 1 case in outer lower quadrant. Most of the cases showed a well-defined nodule grossly, including pushing growth under the microscope in 13 cases, being completely separated from the surrounding breast tissue in 1 case, and infiltrating growth in 1 case. Among them, 12 cases were classic subtype and composed of occasional spindle cells with varying intervals of collagen fiber bundles; eight cases had a small amount of fat; one case had focal cartilage differentiation; one case was epithelioid subtype, in which epithelioid tumor cells were scattered in single filing or small clusters; one case was schwannoma-like subtype, and the tumor cells were arranged in a significant palisade shape, resembling schwannoma, and one case was invasive leiomyoma-like subtype, in which the tumor cells had eosinophilic cytoplasm and were arranged in bundles, and infiltrating into the surrounding mammary lobules like leiomyoma. Immunohistochemical studies showed that the tumor cells expressed desmin (14/15) and CD34 (14/15), as well as ER (15/15) and PR (15/15). Three cases with histologic subtypes of epithelioid subtype, schwannoma-like subtype and infiltrating leiomyoma-like subtype showed RB1 negative immunohistochemistry. Then FISH was performed to detect RB1/13q14 gene deletion, and identified RB1 gene deletion in all three cases. Fifteen cases were followed up for 2-100 months, and no recurrence was noted. Conclusions: Myofibroblastoma is a rare benign mesenchymal tumor of the breast. In addition to the classic type, there are many histological variants, among which the epithelioid subtype is easily confused with invasive lobular carcinoma. The schwannoma-like subtype is similar to schwannoma, while the invasive subtype is easily misdiagnosed as fibromatosis-like or spindle cell metaplastic carcinoma. Therefore, it is important to recognize the various histological subtypes and clinicopathological features of the tumor for making correct pathological diagnosis and rational clinical treatment.

Cytopathological findings of intranodal palisaded myofibroblastoma: Case report and review of the literature.

INTRODUCTION: Intranodal palisaded myofibroblastoma (IPM) is an exceedingly rare benign mesenchymal tumor of the lymph nodes. Magnetic resonance imaging (MRI) findings are unspecific, which may present diagnostic challenges to fine-needle aspiration cytology (FNAC). The histological and immunohistochemical features of IPM are unique. CASE REPORT: A previously healthy 40-year-old male patient presented a slow-growing solitary left inguinal mass. FNAC revealed clustered cells within a metachromatic stroma, single spindle cells without atypia, hemosiderin pigment, and siderophages. An MRI showed a central hyperintense septum in fat-suppressed, T2-weighted sequences. The excised lymph node contained central haphazard fascicles of spindle cells with focal nuclear palisading, hemosiderin pigment, extravasated erythrocytes, and hemorrhagic areas. Vimentin and smooth muscle actin were diffusely positive. Amianthoid collagen fibers were not clearly observed. CONCLUSION: IPM is an extremely rare mesenchymal benign intranodal tumor that should be included in the differential diagnosis of spindle cell lesions in the inguinal region.

Myofibroblastoma in the Liver: A Case Report and Review of Literature.

Myofibroblastoma is a rare benign mesenchymal tumor first described in the breast. It is also known as mammary-type myofibroblastoma outside of the breast, more frequently located along the embryonic milk line. Exceptionally, myofibroblastoma can occur at visceral locations. We present a case of myofibroblastoma detected incidentally in the liver. A well-circumscribed mass, grossly measuring 6.2 cm in the liver parenchyma, was found on imaging studies. Histologically, the lesion is characterized by benign spindle cells in a hyalinized collagenous stroma, with positive staining for SMA and ER, focal positivity for CD34, negative for desmin, and loss of RB1. This rare tumor at such an unusual location makes it diagnostically challenging, especially on core biopsy of the lesion. To our knowledge, this is the second case of myofibroblastoma in the liver reported in the English literature and the first such case with a detailed pathology description.

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 Sigmoid Colon in an Infant: A Case Report and Literature Review.

Inflammatory myofibroblastic tumor (IMT) infrequently involves the sigmoid colon, and has not previously been described in an infant sigmoid colon.An inflammatory myofibroblastic tumor arose from the sigmoid colon of an 11-month-old boy, confirmed by anaplastic lymphoma kinase (ALK), smooth muscle actin (SMA) and desmin immunohistochemical staining. The patient recovered well after complete resection of the tumor.Sigmoid IMT can occur in infancy. This eighth case is the youngest so far. The child did well after surgical resection.