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 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 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.

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.

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.

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.

Inflammatory myofibroblastoma mimicking cavernous hemangioma in the liver.

A 37-year-old female patient was admitted to the hospital with a large liver mass, diagnosed as hepatic inflammatory myofibroblastic tumour (HIMT), characterized by unique radiographic features and predominantly occurring in adults. HIMT consists of myofibroblast spindle cells infiltrated by plasma cells and/or lymphocytes, with an unclear aetiology linked to factors like infection and immune response. Treatment typically involves surgical resection, with chemotherapy or targeted therapy options for cases of incomplete resection or metastasis, emphasizing the need for precise diagnosis and tailored treatment strategies.

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.

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 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.

Superficial myofibroblastoma of the lower female genital tract: A clinicopathological analysis of 15 cases.

OBJECTIVE: To describe the clinicopathological features and differential diagnoses of 15 cases of superficial myofibroblastoma, a rare mesenchymal tumor involving the lower female genital tract. METHODS: The clinicopathological data and immunohistochemical findings were retrospectively analyzed in 15 cases of superficial myofibroblastoma. Meanwhile, a systematic literature review was conducted. RESULTS: The age of patients ranged from 34 to 73 years (median, 49 years). Most patients presented with nodular or polypoid masses ranging in size from 0.4 cm to 6.5 cm. Twelve tumors were located in the vagina, two in the vulva, and one in the cervix. Microscopically, the tumor was located in the subepithelial tissue, with a clear boundary and without capsule on the surface. The tumor cells were spindle, oval, stellate or wavy, and arranged in various architectural patterns of reticular, fascicular, wavy and disorderly patterns. There were no obvious cellular atypia and mitotic figures. Thin collagen fibers and thin-walled vessels could be observed in all cases. Most cases were diffusely and strongly reactive to Vimentin (12/12), Desmin (14/15), ER (15/15) and PR (13/14). Variable immunoreactivity for CD34 (8/15), Caldesmon (2/8), SMA (4/14) and CD99 (4/5) were observed. The tumors showed a low Ki67 proliferative index (≤5 %). Follow-up information was available in 10 patients and there was no evidence of recurrence or metastasis. CONCLUSIONS: Superficial myofibroblastoma is a rare benign tumor that originates from the hormone-sensitive, subepithelial mesenchymal tissue of the lower female genital tract, and should be differentiated from other mesenchymal tumors.

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.

Diagnostic Challenges of Intra-operative Frozen Consultation for Mammary Epithelioid Myofibroblastoma.

Myofibroblastoma (MFB) of the breast is a rare benign neoplasm that exhibits several morphologic variants and presents diagnostic challenges for pathologists, especially in recognizing intra-operative frozen sections. In order to raise awareness of this tumor and avoid misdiagnosis, we describe a case of a 38-year-old female patient diagnosed as epithelioid MFB. This painless tumor was well-circumscribed, found in the left breast and was physically examined over a period of six months. Histologically, this tumor was predominantly composed of epithelioid cells, which arranged as single cells, small clusters or nests. Tumor stroma was collagenized with spindle cells, adipose and focal myxoid areas. This case was misinterpreted as invasive carcinoma in the frozen section. The immunohistochemical profile demonstrated positivity for Vimentin, desmin, SMA, calponin, CD34, ER, PR and AR, whereas pan-keratin, keratin 7, keratin 34ßE12, keratin 5/6, EMA, p63 and S100 were negative. RB1 was abnormally negative, confirming the diagnosis of epithelioid MFB. Making a correct diagnosis is primarily dependent on awareness by the pathologist of this unusual variant of MFB and careful integration of clinicopathologic findings to avoid potential diagnostic pitfalls.

Liver mesenchymal neoplasms: something old, something new.

Histological examination of liver biopsies and resection specimens remains the gold standard to establish a definitive diagnosis of liver lesions. While hepatocellular carcinoma remains the most commonly encountered liver lesion on mass-directed biopsies, surgical pathologists must be aware of other entities that may pose diagnostic challenges, as an accurate diagnosis is key for patient management. Mesenchymal tumours of the liver are relatively uncommon, therefore many pathologists are unfamiliar with these tumours. While the clinical presentation and radiological features of these lesions often overlap, careful attention to histological clues can assist in weeding out various congeners to arrive at the most accurate diagnosis. An additional challenge when diagnosing mesenchymal tumours is the specimen type, as mass-directed core biopsies are limited and have become standard clinical practice. Besides careful attention to histological features, radiological findings and clinical history, immunohistochemical analysis and molecular studies have become of immense diagnostic value. In this review, we discuss several common and rare mesenchymal hepatic lesions as defined in the current World Health Organization (WHO) classification and most up-to-date literature. We also discuss immunohistochemistry panels and relevant molecular findings that may assist in rendering an accurate diagnosis when encountering these lesions in daily practice.

Mammary-type Myofibroblastoma with Leiomyomatous Differentiation: A Rare Variant with Potential Pitfalls.

Myofibroblastoma is a rare, benign stromal tumor with a diverse morphologic spectrum. Mammary-type myofibroblastoma (MTMF) is the extra-mammary counterpart of this neoplasm and its occurrence throughout the body has become increasingly recognized. Similar morphologic variations of MTMF have now been described which mirror those seen in the breast. We describe a case of intra-abdominal MTMF composed of short fascicles of eosinophilic spindle cells admixed with mature adipose tissue. The spindle cells stained diffusely positive for CD34, desmin, smooth muscle actin, and h-caldesmon by immunohistochemistry. Concurrent loss of RB1 (13q14) and 13q34 loci were confirmed by fluorescence in situ hybridization whereas anchored multiplex PCR and whole transcriptome sequencing did not reveal any pathognomonic fusions suggesting an alternative diagnosis. To the best of our knowledge this is the first documented case of leiomyomatous variant of MTMF.

Intranodal Palisaded Myofibroblastoma: A Diagnostic Differential for Inguinal Lymphadenopathy.

BACKGROUND Benign tumors of the lymph nodes are rare and are not usually considered in the differential diagnosis in cases of lymphadenopathy because reactive hyperplasia, lymphoma, and metastatic carcinoma are the most likely causes of enlarged nodes. Intranodal palisaded myofibroblastoma (IPM) is a very rare benign mesenchymal tumor of the lymph nodes most often affecting but not limited to the inguinal region, with up to 92 cases reported in the English literature. The cell of origin is the intranodal differentiated smooth muscle cell or myofibroblast. Although the pathophysiology of IPM remains unclear, theories about viral oncogenesis and mutational changes in the ß-catenin gene with subsequent abnormal expression of ß-catenin and cyclin D1 have been raised. CASE REPORT We report a case of IPM in a 48-year-old man who presented with a mass in the left groin, with inconclusive imaging. The typical histologic findings of smooth muscle actin, cyclin D1, and ß-catenin positive intranodal spindle cell proliferation with characteristic palisades, amianthoid fibers, collagenous bodies, lack of atypia, and very low mitotic count, together with characteristic profile on ancillary testing, confirmed the diagnosis. In addition to staining with smooth muscle actin, cyclin D1 and ß-catenin, immunohistochemical studies showed focal positivity with desmin, a finding previously reported in 2 of the published cases. Surgical excision is usually curative, with a 6% recurrence rate and no reported cases of locally aggressive disease or malignant transformation. CONCLUSIONS Although rare, IPM should be included in the differential diagnosis of isolated lymphadenopathy.