Inflammatory myofibroblastic tumor: comparison of clinicopathologic, histologic, and immunohistochemical features including ALK expression in atypical and aggressive cases

Insights into inflammatory myofibroblastic tumor: A complex and challenging diagnosis

Inflammatory myofibroblastic tumor (IMT), also known as inflammatory pseudotumor or plasma cell granuloma, is an uncommon soft tissue tumor of mesenchymal origin with low to intermediate malignant potential. IMTs are most commonly located in the lung, abdomen/pelvis, or retroperitoneum, primarily affecting children and young adults. Although metastasis is rare, IMTs can recur after surgical resection, as oftentimes resection is limited due to infiltration with surrounding tissue. Here, we present a challenging case of IMT in a 22-year-old male who presented with chest pain and shortness of breath. Extensive diagnostic workup, including multiple biopsies and imaging studies, raised suspicion of malignancy, though initial biopsies failed to confirm a diagnosis. This case highlights the diagnostic difficulties and the importance of a coordinated approach in the diagnosis and management of IMT.

Pediatric-type Myoid Neoplasms of Somatic Soft Tissue: A Clinicopathological and Molecular Genetic Study of 78 Tumors, Highlighting Indolent Clinical Behavior and Frequent SRF Gene Rearrangements

Soft tissue tumors with smooth muscle differentiation are rare in pediatric patients. Despite often showing morphologic features sufficient for classification as "leiomyosarcoma" in adults (eg, high cellularity and mitotic activity), clinical follow-up has shown only indolent behavior. The pathological features of recently reported SRF-rearranged "cellular myofibromas/myopericytomas," typically occurring in children, overlap with those of true smooth muscle tumors. We studied a large series of pediatric tumors with morphologic and immunohistochemical evidence of smooth muscle differentiation, with the goals of better understanding their natural history and molecular genetic features. Seventy-eight tumors were identified in 45 males and 33 females, with a median age of 10 years. Clinical follow-up (50 patients; median, 45.5 months) disclosed local recurrence in 7 patients (15%). No metastases or deaths because of disease occurred. Group 1 (73/78) tumors consisted of cellular fascicles of mildly to at most moderately atypical, bland, ovoid to spindled cells with distinctly eosinophilic cytoplasm, appreciable mitotic activity (median, 5/50 high-power fields), and no necrosis. Group 2 tumors (5/78) showed greater cellularity, significant nuclear pleomorphism, and brisk mitotic activity (median, 59/50 high-power fields). Subsets of group 1 tumors harbored SRF rearrangements (16/47), and all group 2 tumors showed TP53 biallelic inactivation (5/5). SRF fusion partners included CITED1, NCOA2, C3orf62, RELA, ARGFXP1, ARNTI2, ICA1L, and unknown (n = 1). We conclude that the prognosis for pediatric tumors with smooth muscle differentiation that fall into group 1 is excellent. SRF rearrangements are present in a significant minority of tumors, typically showing features of smooth muscle rather than myopericytic differentiation. A smaller subset with more worrisome morphologic features harbor biallelic inactivation of TP53. To emphasize their unique features, we propose the term "pediatric-type myoid neoplasms of somatic soft tissue" rather than simply "leiomyoma" or "leiomyosarcoma" for group 1 tumors, and the designation of leiomyosarcoma in children should be limited to group 2 tumors.

Synchronous presentation of hepatic inflammatory pseudotumour and hepatocellular carcinoma within the same nodule: a case report

Inflammatory pseudotumours (IPTs) are benign lesions that rarely occur in the liver, usually presenting as mass-forming lesions characterized by bland spindle cells intermingled with a mixture of inflammatory cells, etiologically related to inflammatory response caused by infection and trauma. The combination of hepatic IPTs with primary liver malignancies is anecdotal to our knowledge. This study reports a case of hepatic IPT synchronously arising at the periphery hepatocellular carcinoma (HCC) in a 66-year-old male patient who had 2 liver biopsy procedures before undergoing surgical resection. The occurrence of IPT in this case is perceived as a reactive inflammatory response due to traumatic event (prior biopsy procedures) and fungal infection (Cystobasidium slooffiae) after conducting a thorough evaluation at the histological, immunohistochemical, and molecular levels to rule out the potential differential diagnoses and to identify any infectious agents.

Inflammatory myofibroblastic tumors of the colon in pediatrics: clinical presentation, management, and outcomes-A case report and systematic review of literature

PURPOSE

Inflammatory myofibroblastic tumors (IMTs) of the colon represent an exceptionally rare entity in the pediatric population. This systematic review aims to comprehensively analyze the clinical presentation, diagnostic workup, management strategies, and outcomes of colorectal IMTs in children.

METHODS

A systematic literature review was conducted across multiple electronic databases (inception to January 2025), including MEDLINE (via PubMed), Embase, Cochrane, Web of Science, and Google Scholar. Two independent reviewers screened abstracts, reviewed studies, and extracted data on all reported cases of colorectal IMTs in the pediatric population, including one previously unreported case from our institution.

RESULTS

Including our case, 53 pediatric patients with colorectal IMTs were identified from 39 studies. The mean age at diagnosis was 7 years (range: 5 months-17 years) with a slight female preponderance. The IMTs comprised a wide range of anatomic locations with rectum (27%) and ascending colon (24%) being the most common. Abdominal pain (54%), gastrointestinal bleeding (29%), and fever (21%) were the predominant symptoms. Anemia was the most common laboratory abnormality (62%). Surgical resection was the primary treatment modality in 98% of cases. After a mean follow-up of 38 months ( range: 3-181 months), the local recurrence rate was 11%, with no distant metastases reported.

CONCLUSION

Colorectal IMTs in children present diagnostic and therapeutic challenges. While complete surgical resection remains the gold standard treatment, emerging therapies such as ALK inhibitors and NSAIDs warrant further investigation. The potential for late recurrence mandates long term follow-up.

Inflammatory Myofibroblastic Tumor: An Updated Review

Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm that is characterized by a proliferation of myofibroblastic and fibroblastic spindle cells, accompanied by an inflammatory infiltrate that is abundant in plasma cells, lymphocytes, and eosinophils. IMT can arise in various anatomical locations but most commonly occurs in the abdominal cavity, retroperitoneum, and lung, particularly in children and young adults. IMT typically demonstrates local invasion or recurrence, whereas metastasis is rare. IMTs pose a diagnostic challenge because of their overlapping morphological characteristics with a heterogeneous group of nonneoplastic and neoplastic lesions. Precise diagnosis is crucial for optimal management and accurate prognostication. Despite recent advancements in IMT diagnosis and treatment, its biological complexity and clinical management remain challenging due to significant histological heterogeneity and molecular genetic diversity. This review provides comprehensive updates on the clinical, molecular, and pathological characteristics of IMT, highlighting the diagnostic approaches and key differential diagnoses.

From benign appearance to malignant truth: a case report of mesenteric dedifferentiated liposarcoma with inflammatory myofibroblastic tumor-like features

Dedifferentiated liposarcoma (DDLPS) with inflammatory myofibroblastic tumor (IMT)-like features is a rare and diagnostically challenging variant of soft tissue sarcoma. We report the case of a 74-year-old man who presented with a mesenteric mass in 2022 and recurrent tumors in 2024. Tissue from both primary and recurrent tumors were submitted to our reference center for pathological reevaluation, with a suspicion of IMT being suspected. Although the tumors exhibited morphological characteristics consistent with those observed in IMT, they displayed distinctive histological, immunohistochemical and molecular features suggestive of DDLPS with IMT-like features, including amplification of the MDM2 gene. This report highlights the morphological spectrum of DDLPS, the diagnostic role of molecular pathology, and the importance of differentiating this aggressive neoplasm from benign entities such as IMT.

Thoracic Frozen Section Pitfalls: Lung Adenocarcinoma Versus Selected Mimics

CONTEXT.—

Intraoperative (frozen section) analysis of lung lesions (nodules, masses, ground-glass opacities) can occasionally be diagnostically challenging.

OBJECTIVE.—

To describe selected pitfalls in thoracic frozen sections with a focus on the differential diagnosis between adenocarcinoma and its mimics, and to provide tips to prevent misinterpretation.

DATA SOURCES.—

Peer-reviewed literature and the author's experience.

CONCLUSIONS.—

A common challenge in thoracic frozen sections is the differential diagnosis between lung adenocarcinoma and its mimics. Diagnostic difficulties arise because mimics of adenocarcinoma often entrap reactive lung epithelium that can appear atypical on frozen section slides. Entities that can be misinterpreted as adenocarcinoma include ciliated muconodular papillary tumor/bronchiolar adenoma, hamartoma, inflammatory myofibroblastic tumor, and pulmonary Langerhans cell histiocytosis. Knowledge of the key clinical, radiologic, and histologic features of these entities can help prevent overdiagnosis of adenocarcinoma. Pathologic findings that facilitate the distinction between adenocarcinoma and its mimics at frozen section include the appearance and contour of the lesion at low magnification, growth patterns, cilia, stromal features, shape of the epithelial cells (cuboidal versus columnar), nuclear features of malignancy (crowding, hyperchromasia, irregular contours), and abruptness of the junction between the lesion and adjacent uninvolved lung. Knowledge of the clinical context, imaging findings, and the surgical consequence of the intraoperative diagnosis can also prevent diagnostic errors. Finally, since adenocarcinomas of the lung are often relatively bland and lack the stromal desmoplasia seen in adenocarcinomas of other organs, familiarity with the morphologic spectrum of lung adenocarcinomas at frozen section analysis is important.

Case Report: Intestinal metastasis from ALK-rearranged pulmonary pleomorphic carcinomas mimicking inflammatory myofibroblastic tumors

Lung carcinomas usually spread to the liver, lungs, pleura, pericardium, adrenal glands, brain, and bones. Anaplastic lymphoma kinase gene (ALK) fusion occurs in approximately 5% of non-small cell lung cancer (NSCLC) cases and most frequently in adenocarcinoma. Here, we report a rare case of intestinal metastasis originating from pulmonary pleomorphic carcinoma in a 49-year-old male heavy smoker. At the local hospital, the patient was initially considered to have an ALK-positive intestinal tumor, leading to a differential diagnosis of inflammatory myofibroblastic tumor (IMT). Due to the tumor's peculiar morphology (including epithelioid and spindle cell components), pathologists of the local hospital sent slides of the case to our hospital for further consultation. Immunohistochemical analysis revealed that the epithelioid and spindle neoplastic cells were positive for CK7, TTF1, and ALK-V. Fluorescence in situ hybridization (FISH) confirmed the presence of the echinoderm microtubule-associated protein-like 4 (EML4):: ALK fusion. Based on these findings, we established the final diagnosis as intestinal metastasis of ALK-positive pulmonary pleomorphic carcinoma. A subsequent enhanced CT scan of the chest revealed a 3.0 cm solid mass in the right upper lung, further supporting the diagnosis of intestinal metastasis originating from pulmonary pleomorphic carcinoma. In conclusion, this case exhibited highly unusual clinicopathological features that could easily lead to misdiagnosis as primary intestinal tumors with ALK rearrangement. Pathologists must know this possibility to ensure accurate diagnosis and appropriate management.

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.

Inflammatory myofibroblastic tumor of the adrenal gland: A case report

INTRODUCTION AND IMPORTANCE

Inflammatory myofibroblastic tumor (IMT) is an extremely rare sarcoma mainly reported in the lung. The adrenal gland, however, is an extremely rare site of occurrence. Herein, we report a case of a large adrenal mass with no contributory imaging features presenting a challenging pathological diagnosis.

CASE PRESENTATION

A healthy 32-year-old male patient, with no personal nor family history, presented with loss of body weight and condition developing for two months. Physical examination revealed no abnormalities with a soft and depressible abdomen and absence of palpable lump. Circulating Chromogranin A and catecholamine metabolites were within normal range. The preoperative imaging features were noncontributory. The pathological examination on biopsy specimen concluded to a spindle cell proliferation set in a chronically inflamed background suggesting the diagnosis of IMT. The patient, subsequently, underwent radical nephrectomy unveiling a 25 cm adrenal mass. Pathological findings on resection specimen confirmed the diagnosis of IMT of the left adrenal gland.

CLINICAL DISCUSSION

Due to their rarity in the adrenal gland and their noncontributory radiological features, IMTs are typically not considered as a potential diagnosis in this location. As a result, this condition is often underdiagnosed. In this setting, suspicion for IMT should be raised when spindle cell histology is observed.

CONCLUSION

It is fundamental for practicians to keep this entity in mind as the treatment consists of complete tumor extirpation. The latter being the only guarantee of recurrence free follow up.

Mesenchymal Tumors of the Liver: An Update Review

Hepatic mesenchymal tumors (HMTs) are non-epithelial benign and malignant tumors with or without specific mesenchymal cell differentiation. They are relatively uncommon. Except for mesenchymal hamartoma, calcified nested stromal-epithelial tumor, and embryonal sarcoma, most mesenchymal lesions are not specific to the liver. Pathologists face challenges in diagnosing HMTs due to their diverse morphologies and phenotypic variations. Accurate diagnosis is critical for directing appropriate patient care and predicting outcomes. This review focuses on mesenchymal tumors with a relative predilection for the liver, including vascular and non-vascular mesenchymal neoplasms. It provides a thorough and up-to-date overview, concentrating on clinical and pathological features, differential diagnosis, and diagnostic approaches.

Superficial ALK-rearranged myxoid spindle cell neoplasms: Clinicopathologic and molecular analysis of two cases and a review of the literature

Superficial anaplastic lymphoma kinase (ALK)-rearranged myxoid spindle cell neoplasms are a recently identified subtype of cutaneous soft tissue tumors, distinct for their co-expression of CD34 and S100 and characterized by ALK gene rearrangements. Although 72 cases have been reported primarily as isolated case reports, this tumor subtype has yet to be included in the WHO classification of soft tissue tumors, underscoring the need for further study. In this study, we diagnosed two additional cases, both arising in the dermis and subcutaneous tissue. These tumors exhibited characteristic pathological features, including linear or concentric whorl patterns, prominent myxoid and collagenized stroma, mild cellular atypia, and rare mitotic activity. The presence of infiltrative margins and the potential for recurrence after surgery suggest at least locally aggressive clinical behavior. Immunohistochemically, the tumors diffusely expressed S100 and CD34, with strong ALK-D5F3 positivity, confirmed by ALK gene rearrangement. These findings further expand the clinical and pathological spectrum of ALK-rearranged neoplasms and highlight the need for continued research on their biological behavior and classification.

Inflammatory Myofibroblastic Tumor of the Esophagus and Stomach Successfully Treated With ALK Inhibitor in a Pediatric Patient: A Case Report and Concise Review of Literature

An inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal neoplasm of borderline malignant potential. Nearly half of all IMTs have rearrangement of anaplastic lymphoma kinase (ALK) locus on chromosome 2p23 which can be treated with targeted therapy. Herein, we describe an unusual presentation of IMT involving an anatomical region rarely implicated in this disease process. A 15-year-old male patient came to the ER with dysphagia and coffee ground emesis. On esophagogastroscopy, a nodular luminal obstructing 30 × 50 mm mass in the lower esophagus was found, which was continuous with a large, partially circumferential gastric mass extending from the mid-body to the proximal antrum. Biopsies from esophageal and gastric masses revealed submucosal lesions composed of cytologically bland spindle and epithelioid cells, intermingled with inflammatory infiltrate, for which several immunohistochemical (IHC) stains were performed. The molecular study demonstrated ATIC::ALK fusion. Based on morphological, IHC, and molecular study findings, the diagnosis of ALK-positive IMT was rendered. Because surgical excision was deemed infeasible, the patient was started on ALK-inhibiting therapy with crizotinib. The patient responded well with no evidence of residual or recurrent disease on follow-up imaging or surveillance esophagogastroduodenoscopy. Crizotinib was ultimately discontinued after 10 months of therapy, and the patient continues to undergo surveillance imaging for monitoring of disease burden.

Gastric inflammatory myofibroblastic tumor invading the esophagus and spleen: a rare case report and literature review

Inflammatory myofibroblastic tumor (IMT) is a rare neoplasm with intermediate biological potential. The stomach is an uncommon site for IMTs, and gastric IMTs are typically confined to the submucosal layer. This report presents a rare case of a 29-year-old woman with a gastric IMT located in the gastric fundus, exhibiting local invasion into the esophagus and spleen.

Identification of the molecular characterization and tumor microenvironment of thoracic inflammatory myofibroblastic tumors

BACKGROUND

Inflammatory myofibroblastic tumors (IMTs), rare soft tissue neoplasms, are characterized by a blend of myofibroblastic proliferation and inflammatory features. While generally characterized by slow growth, IMTs can exhibit locally aggressive behavior, and in rare instances, metastasize to distant sites. This study elucidated the clinical characteristics, molecular profile, and tumor microenvironment of thoracic IMTs.

METHODS

We retrospectively analyzed cases of IMTs diagnosed at the National Taiwan University Hospital between 2000 and 2020. ALK immunohistochemistry (IHC) was performed, followed by fluorescence in situ hybridization (FISH) for confirmation. Next-generation sequencing (NGS) was employed to detect unknown oncogenic drivers, and multiplex immunofluorescence staining was used to characterize the tumor microenvironment. Demographic, clinicopathological characteristics, and treatment outcomes were systematically recorded and analyzed.

RESULTS

We identified a total of 8 patients with thoracic IMTs, whose median age of the participants was 33.8 years (range: 18.6-58.7). The disease status of all tumors were early-stage, and all patients underwent surgical excision. ALK fusions were detected in 6 tumors (all spindle-cell patterns), with fusion partners including 3 TPM3, 2 DCTN1, and one EML4. In the remaining 2 tumors without ALK fusion, NGS showed NTRK3 alteration with high gene expressions. Multiplex IHC of three cases identified a pronounced infiltration of macrophages cells within the tumor microenvironment.

CONCLUSION

Patients with thoracic IMT patients are typically young with early-stage disease. ALK fusion were the most common genetic alteration, particularly in spindle-cell patterns. Characterization of the tumor microenvironment indicates the potential of immune profiling in the tumor biology and targeted immunotherapy approaches.

Rare Site of an Inflammatory Myofibroblastic Tumor at the Epididymis: A Case Report

Background

Inflammatory myofibroblastic tumors (IMT) are uncommon with an estimated 150-200 people being diagnosed in the US annually. We describe a healthy adult male who presented with an enlarging, painless scrotal mass. Based on current literature, only nine epididymal inflammatory myofibroblastic tumors have been reported and in this case report we describe the tenth.

Case Presentation

A 40-year-old Caucasian male presented with an enlarging mass near his right testicle with no associative symptoms or obvious etiology. Scrotal ultrasound showed a solid heterogenous mass with internal vascularity. Tumor markers were unremarkable for lactate dehydrogenase (LDH), beta-human chorionic gonadotropin (b-hCG), and alpha-fetoprotein (AFP). A right inguinal approach was performed. A 2-3 cm round mass adjacent to the tail of the epididymis was excised with clear margins and sent to pathology. Histology confirmed a 2.4 cm inflammatory myofibroblastic tumors with scattered positivity for smooth muscle actin, negative pancytokeratin, and negative anaplastic lymphoma kinase. Patient recovered well with no reoccurrence at this time.

Conclusion

Inflammatory myofibroblastic tumors recurrence rate is <2%; however, some literature suggests higher depending on location and immunohistochemical profile. The expertise of pathologists, utilization of morphology, and immunohistological profile are all crucial in accurate diagnoses of these lesions. Literature reports some lesions have demonstrated metastatic tendencies and therefore complete excision of the mass is the recommended therapy of choice. This case highlights the increasing need to include IMT in differential diagnoses for patients presenting with painless lumps even in unlikely locations. While there is little data on epididymal tail mass recurrence rate potential, we report no current recurrence after complete excision of the mass.

Case report: Musculoskeletal metastastic inflammatory myofibroblastic tumor (IMT) treated by sequential ALK-TKI with longterm response

Inflammatory myofibroblastic tumors (IMTs) are known to be associated with rearrangements of the anaplastic lymphoma kinase (ALK) gene. The treatment of this type of tumor includes systemic therapies such as chemotherapies or anti-inflammatories; in recent years, targeted anti-ALK therapies have emerged and became the standard of care in ALK rearranged patients. We aimed to present a rare case of musculoskeletal IMT with ALK rearrangement, characterized by metastatic evolution and enhanced responses to sequential treatment with all ALK-TKI. We have outlined a potential treatment pathway involving sequential ALK-TKI targeted therapies and successive local interventions to control the cancer.

What is new in fibroblastic/myofibroblastic tumors in children

Fibroblastic and myofibroblastic neoplasms represent about 12% of pediatric soft tissue tumors. Most of these neoplasms in children are either benign or locally aggressive with rare metastasis, while malignant cases are uncommon. Diagnosing these tumors is challenging due to overlapping morphologies and the limited utility of immunohistochemistry. Advances in molecular techniques, especially RNA sequencing, have improved our understanding of the molecular drivers of these tumors, leading to better classification. Key molecular alterations, such as RTK and MAPK activation, are central in the development of tumors like infantile fibrosarcoma (IFS) and inflammatory myofibroblastic tumors (IMT). The identification of alternative fusions in IFS and IMT underscores the importance of an integrated diagnostic approach. Furthermore, new RTK-driven lesions, now included in the WHO's "NTRK-rearranged mesenchymal neoplasms", have been identified. This review provides an update on recent findings in RTK-driven myofibroblastic tumors and highlights novel entities still in need of classification.

"Update on pediatric primary liver tumors"

Liver masses are common in children, however primary malignant neoplasms are rare, representing only 1% of all pediatric cancers. Hepatocellular neoplasms are the most common primary liver malignancies and hepatoblastoma (HB) is the most frequently diagnosed. The incidence of HB, which is increasing, is approximately of 2 cases per million in the United States, followed by hepatocellular carcinoma (HCC). Pediatric primary liver tumors of mesenchymal origin are less common, except for benign vascular tumors (hemangiomas). Malignant mesenchymal neoplasms represent approximately 10-15% of all, the most common being embryonal sarcoma and malignant rhabdoid tumor. Malignant vascular tumors are rare, but epithelioid hemangioendothelioma (EHE) and angiosarcoma can be seen in children. The development and adoption of consensus diagnostic, therapeutic and risk-stratifying approaches for pediatric patients with malignant liver tumors has been historically challenged by their rarity and by their diverse clinical and histological appearance. On-going collaborative efforts of international consortia including the Children's Oncology Group (COG) in North America, the German Society of Paediatric Oncology and Haematology (GPOH), the Societe Internationale d' Oncologie Pediatrique Liver Tumor Study Group (SIOPEL) in Europe and the Japanese Liver Tumor group (JPLT), have made significant contributions to understanding the clinical and histopathological features, as well as the underlying biology of pediatric liver tumors, in particular HB. A new classification of pediatric liver tumors drafted at the international consensus meeting held in Los Angeles, has been incorporated in the recent WHO classification and is currently used by the PHITT (Paediatric Hepatic Malignancy International Tumour Trial) and other therapeutic protocols. This manuscript provides an overview of salient diagnostic features and updates in classification and molecular characterization for the most common pediatric primary liver neoplasms. It also includes a brief overview of other less common but relevant tumors, which should be considered in the differential diagnosis.

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.

A rare case of inflammatory myofibroblastic tumour of the thigh : A case report and literature review

Towards the beginning of the twentieth century, inflammatory myofibroblastic tumors were described as neoplasms characterized by myofibroblastic spindle cells with an infiltrate of inflammatory cells. These rare tumors occur mainly in children and young adults with a preferential pulmonary and abdominal location. They have intermediate biological potency with a tendency to local recurrence and rarely metastasize. We describe the case of an adolescent who presented with an inflammatory myofibroblastic tumor of the thigh, a very rare entity that has only been reported in the literature as case reports, and its clinical, radiological, echographic and MRI appearance. The patient underwent complete surgical resection of the mass with healthy margins and did not receive any additional treatment. No sign of recurrence was detected after 6 months of follow-up.

Radiologic findings of an adolescent epithelioid inflammatory myofibroblastic sarcoma

Epithelioid inflammatory myofibroblastic sarcoma, a variant of the inflammatory myofibroblastic tumor, is a rare tumor that is not well described in the radiologic literature. We present a case of a 14-year-old male adolescent who presented with fever, fatigue, and weight loss symptoms and was found to have an abdominal mass on contrast enhanced CT. Initial differentials included lymphoma, pheochromocytoma, desmoid, and sarcoma, and pathological evaluation revealed an epithelioid inflammatory myofibroblastic sarcoma. The mass was separate from the surrounding structures of the left upper abdomen with unique radiologic features not previously described in the literature. Prior literature examples of epithelioid inflammatory myofibroblastic sarcoma described a heterogenous, enhancing lobulated mass, and our case was a lobulated, avidly enhancing homogenous mass on CT with surrounding inflammation and avid uptake on PET/CT. In addition to the imaging features, we describe the surgical findings, the pathologic features of the tumor, and the oncologic treatment of this patient. This case highlights the importance of including rare tumors such as epithelioid inflammatory myofibroblastic sarcoma as a potential differential consideration of an avidly enhancing homogenous abdominal mass in an adolescent.

Added-value of dynamic contrast-enhanced MRI to conventional MRI for the differentiation between inflammatory myofibroblastic tumor and squamous cell carcinoma in the sinonasal region

PURPOSE

The purpose of this study was to evaluate the additional value of dynamic contrast-enhanced (DCE) MRI and diffusion weighted MRI (DWI) in differentiation between inflammatory myofibroblastic tumor (IMT) and squamous cell carcinoma (SCC) in the sinonasal cavity.

METHODS

Patients with pathologically proven IMT and SCC in the sinonasal region were enrolled in this retrospective study. All participants underwent conventional MRI and dynamic contrast-enhanced MRI, while a subset of them performed DWI. All the MRI parameters were independently analyzed by two investigators.

RESULTS

This retrospective study included 21 patients with IMT and 55 patients with SCC. Significant differences were found in the conventional MR imaging features including mass margin, T2 signal intensity and track sign of maxillary (p < 0.05). For DCE-MRI features, significant differences were found in progressive centripetal continual enhancement and CImax (p < 0.001 and p = 0.026, respectively). A marginal significant difference was found in ADC values between IMT (0.86 ± 0.59) and SCC (1.14 ± 0.25) (p = 0.061). The conventional MRI analysis revealed that the combination of mass margin and track sign of maxillary yielded an accuracy of 81.6%. Using a combination of progressive centripetal continual enhancement on DCE-MRI and track sign of maxillary in multivariate logistic regression analysis, the accuracy was elevated to 92.1%.

CONCLUSION

The incorporation of DCE-MRI features into conventional MRI showed improved diagnostic performance in differentiating IMT from SCC in the sinonasal region. The novel progressive centripetal continual enhancement on DCE-MRI is the most effective feature of IMT.

A Rare Case of Inflammatory Myofibroblastic Tumor Mimicking Fibrous Adhesions Resulting in Bowel Obstruction

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumors of unknown etiology composed of myofibroblastic cells admixed with inflammatory cells. Presented is a 72-year-old male hospitalized for severe abdominal pain and hematochezia with onset of associated symptoms of fever and sweats a few hours prior to abdominal pain. A computed tomography (CT) demonstrated left colonic thickening interpreted as partial obstruction, gross adhesions, and ischemia. At surgery, marked bowel ischemia from the distal transverse to proximal sigmoid colon was seen with extensive gross adhesions. Histopathology revealed a mesenteric mass chiefly composed of stellate-to-spindled myofibroblastic cells and fibrous adhesions, intermixed with lymphocytes, histiocytes, and plasma cells. The tumor was positive for desmin, smooth muscle actin, and keratin; tumor staging, grade, and postsurgical follow-up were not completed as the patient expired postoperatively. Illustrated is a rare pathologic mimic of ischemic colitis with fibrous adhesions, IMT. Thus, it should not be assumed that fibrous adhesions are always the etiology of obstruction when "adhesions" between sections of bowel are noted radiologically or surgically.

Pediatric skull inflammatory myofibroblastic tumor: a rare case report and literature review

Inflammatory myofibroblastic tumors (IMTs) represent rare neoplasms, particularly infrequent in the pediatric skull. We present a novel case of a newborn male with a 5 cm right temporal mass and discuss current diagnostic and treatment options for IMTs. A multidisciplinary effort to surgically remove the lesion was successful, and the patient's skull defect healed without neurological deficits. The etiology of IMTs remains elusive, with proposed associations with chromosomal mutations in the anaplastic lymphoma kinase (ALK) gene. Surgical excision remains the primary treatment for IMTs. Promising pharmacological treatments, like Crizotinib, warrant further research into understanding potential alternatives in IMT management.

Mesenchymal Tumors of the Head and Neck

The majority of neoplasms of the head and neck are of epithelial origin primarily including mucosal squamous cell neoplasms (papillomas; squamous cell carcinoma) as well as salivary gland neoplasms. However, the full spectrum of mesenchymal neoplasms (benign and malignant) typically arising in soft tissue sites may also develop in superficial layers of the upper aerodigestive tract. The diversity of mesenchymal neoplasms arising in the head and neck is beyond the scope of this article, and our focus will be on some of the more common and/or diagnostic problematic mesenchymal tumors occurring in the sinonasal tract, oral cavity/odontogenic, pharynx, larynx, and neck.

An Inflammatory Myofibroblastic Tumor With a Novel ALKV1180L Mutation Leading to Acquired Resistance to Tyrosine Kinase Inhibitors

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal neoplasm that can locally recur and potentially metastasize. Approximately 50% of IMTs harbor rearrangements in the gene encoding anaplastic lymphoma kinase (ALK), a receptor tyrosine kinase that can be therapeutically targeted with tyrosine kinase inhibitors (TKIs). With successful application of TKI in ALK-positive nonsmall cell carcinoma (NSCLC), ALK inhibitors are often first-line treatments for patients with unresectable or metastatic IMTs. Although acquired resistance to these agents may develop, resistance mechanisms are sparsely reported for IMTs. Here we report a case of a 71 year-old man with metastatic pulmonary IMT harboring a DCTN1::ALK fusion that progressed during alectinib TKI treatment. Whole exome sequencing of an enlarging metastatic lesion in right 4th rib revealed a novel p.V1180L mutation in the ALK tyrosine kinase domain as the mechanism of acquired resistance. To our knowledge, this is the first report of acquired p. V1180L mutation in IMTs treated with TKIs. In cases of ALK-positive IMTs that progress on TKI therapy, targeted sequencing for acquired ALK mutations may inform clinical decisions to adopt second-line therapeutic strategies.

A Rare Endobronchial Tumor in a Pediatric Patient

A pediatric patient who presented with non-specific respiratory symptoms, including mild hemoptysis, wheezing, and eventual respiratory distress, was found to have a rare endobronchial inflammatory myofibroblastic tumor obstructing her right mainstem bronchus. It was diagnosed and initially debulked using bronchoscopy, which helped to stabilize the patient and eliminate the need for supplemental oxygen. The patient subsequently underwent successful removal of the residual tumor with parenchymal-sparing sleeve resection. This case highlights the importance of pursuing appropriate imaging along with diagnostic and therapeutic bronchoscopy for an endobronchial lesion to help manage pediatric patients with persistent respiratory symptoms.

Unusual gastric localization of an inflammatory myofibroblastic tumor: A case report and review of the literature

INTRODUCTION AND IMPORTANCE

Primary inflammatory myofibroblastic tumor is a rare subgroup of mesenchymal tumors. Gastric localization is extremely rare, and patients may present with abdominal pain and a palpable abdominal mass. Here, we present a case of gastric inflammatory myofibroblastic tumor revealed by abdominal pain, which was treated with wide local excision.

CASE PRESENTATION

This report illustrates the case of a 55-year-old female who presented with abdominal pain. Imageology and gastrointestinal endoscopy revealed a posterior gastric mass, which was treated with wide local excision. Immunohistochemical analysis of the specimen confirmed the diagnosis of inflammatory myofibroblastic gastric tumor. The patient had an uneventful postoperative course and she remained in remission after 6 months of follow-up.

DISCUSSION

Inflammatory myofibroblastic tumor is a very rare mesenchymal tumor that usually affects children and young adults. Gastric localization is also very rare and does not typically cause specific clinical symptoms. Surgery is the mainstay of treatment, and resection depends on the size and location of the lesion. The definitive diagnosis is confirmed by immunohistochemical analysis of the specimen.

CONCLUSION

Myofibroblastic tumor is a rare subgroup of mesenchymal tumor. Gastric localization is an uncommon presentation. Surgery is the mainstay of the treatment. Histological analysis of the surgical specimen is essential for a final diagnosis.

Incidentally Detected ALK-Positive Histiocytosis with EML4::ALK Fusion in a Solitary Pulmonary Nodule Following COVID-19 Infection: A Rare Case Report

We hereby report a patient with ALK-positive histiocytosis with localized lung involvement. A 47-year-old woman presented with a solitary pulmonary nodule in the left upper lobe, 7 months after COVID infection. A well-defined 15 mm yellow mass was found in trisegmentectomy specimen. Histopathological examination revealed that the mass was composed of epithelioid and spindle cells with foamy cytoplasms. No necrosis, pleomorphism, or nuclear atypia was detected. The cells were positive for CD68, CD163, PU.1, ALK and negative for KRT, smooth muscle actin (SMA), S100, Melan-A, CD34, STAT6, and BRAF VE1. Flourescence in situ hybridization demonstrated ALK gene rearrangement, and next generation sequencing confirmed EML4::ALK fusion. Lung involvement in ALK-positive histiocytosis is characterized by the presence of pulmonary nodules, which can be seen in all forms of the disease. However, lung involvement is rarely seen in single-system ALK-positive histiocytosis. Our report represents the fourth documented instance of localized lung involvement in ALK-positive histiocytosis, an exceedingly rare occurrence, and it is the third instance with available molecular data.

Inflammatory Myofibroblastic Tumor of the Lung: A Case Report

Inflammatory myofibroblastic tumor (IMT) is a rare mesenchymal tumor classified as an intermediate malignancy that rarely metastasizes. The most common site for IMTs is the lung, though they can develop in various other anatomical locations. Pulmonary IMTs are more common in children and adolescents and are infrequently diagnosed in adults. This case report describes a 49-year-old woman with a history of breast cancer previously treated with subtotal mastectomy and chemotherapy who developed an IMT in the lung. This case emphasizes the rarity of the disease and the associated clinical challenges when managing such cases.

Soft Tissue Fine-Needle Aspiration: Current and Future Impact on Patient Care

Soft tissue neoplasms pose many diagnostic challenges on fine-needle aspiration (FNA), owing largely to their rarity, large number of entities, and histologic diversity. Advances in ancillary testing now allow detection of the characteristic immunophenotypes and molecular alterations for many neoplasms and include reliable surrogate immunohistochemical markers for underlying molecular events that are highly efficient in small biopsies. A morphology-based framework is recommended to guide appropriate differentials and judicious selection of ancillary tests for small biopsies. The accurate diagnosis of soft tissue tumors is crucial for patient management and prognostication, with many potential implications in this era of precision medicine.

Inflammatory myofibroblastic tumor of the maxillary sinus: A case report

Inflammatory myofibroblastic tumors (IMTs) are one of the most complex and rare neoplasms that have been discovered, with varying behavior in different cases. They mostly arise in the thoracic and abdominal cavity, the lungs, retroperitoneum, and extremities. They can also be detected in the head and neck area. IMTs have no age or gender preference which makes them tougher to anticipate. Head and neck IMTs are benign neoplasms with locally aggressive behavior and a low risk of metastatic spread. They have an unknown etiology, and they resemble malignant lesions radiologically. In this case report, we will review the case of a 40-year-old woman with an unusual IMT in the maxillary sinus that presented as a challenge in diagnosis and management.

Epithelioid inflammatory myofibroblastic sarcoma treated with Alectinib: a case report and literature review

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is an extremely rare and aggressive form of inflammatory myofibroblastic tumor. Clinically, it has a high risk of relapse and peripheral organ infiltration, and it responds poorly to conventional chemotherapy. Anaplastic lymphoma kinase (ALK) inhibitors are currently the most effective targeted therapy for EIMS. This report discusses a typical case of abdominal EIMS in a 43-year-old woman. The tumors recurred rapidly within one month after surgery. Alectinib was promptly administered upon diagnosis. However, the patient developed a severe allergic reaction to the medication. After a comprehensive assessment and symptomatic treatment, her condition stabilized, leading to a favorable prognosis. This study summarizes cases of abdominal EIMS, highlights the successful use of Alectinib for treatment, and discusses the management of medication-related complications.

A Case Report of Inflammatory Myofibroblastic Tumor of the Sphenoidal Sinus

Inflammatory myofibroblastic tumor (IMT) is a tumor composed of differentiated myofibroblastic spindle-shaped cells. It occurs in the soft tissues of the abdomen and lungs, and is very rare in the sphenoid sinus. The diagnosis depends on histopathology and immunohistochemistry, and is easily misdiagnosed. Although metastasis is rare, the recurrence rate is high. Surgical resection is the treatment of choice, and where complete resection is difficult, radiation therapy, hormonal therapy, or molecular targeted drug therapy can be administered. We report a rare case of IMT with a primary origin in the sphenoid sinus, which was entirely resected by nasal endoscopy and confirmed by histological examination.

A case report: Pathological complete response to neoadjuvant lorlatinib for Epithelioid inflammatory myofibroblastic sarcoma with EML4-ALK rearrangement

Inflammatory myofibroblastic tumor (IMT) is a rare tumor originating from mesenchymal tissue. Epithelioid inflammatory myofibroblastic sarcoma (EIMS) represents a rare and particularly aggressive variant, associated with a worse prognosis. Almost all EIMS cases exhibits activating anaplastic lymphoma kinase (ALK) gene rearrangements, which suggests that EIMS patients may potentially benefit from treatment with ALK tyrosine kinase inhibitors (TKIs). We presented a case involving a 34-year-old woman who was diagnosed with mediastinal EIMS and had a rare echinoderm microtubule-associated protein-like 4 (EML4) -ALK fusion. Following 15 months of neoadjuvant lorlatinib treatment, the patient underwent a complete surgical resection, resulting in a pathological complete response. Given the heightened risk of postoperative recurrence associated with EIMS, the patient's treatment plan included ongoing adjuvant therapy with lorlatinib. As of the present moment, the patient has achieved an overall survival of over 2 years with no observed tumor recurrence. Consequently, the case offers valuable clinical evidence supporting the potential benefits of neoadjuvant lorlatinib treatment for ALK-positive locally mediastinal EIMS patients, with a demonstrated tolerable safety profile.

Treatment of intracranial inflammatory myofibroblastic tumor with PD-L1 inhibitor and novel oncolytic adenovirus Ad-TD-nsIL12: a case report and literature review

Inflammatory myofibroblastic tumor (IMT) is a rare pathological entity first described in 1939. This lesion is most commonly found in the lungs, but cases involving other systems, such as the central nervous system known as intracranial IMT (IIMT), have also been reported. Diagnosis currently relies on pathological results due to the lack of characteristic imaging changes. Surgical resection is an effective treatment, though the disease is invasive and may recur. Previous literature has reported a high level of programmed death 1 (PD-1) expression in IMT tissues, suggesting that immunotherapy may be effective for this condition. In this case report, we present a middle-aged male who received PD-1 inhibitor and oncolytic adenovirus (Ad-TD-nsIL12) treatment after IIMT resection surgery. This successful approach provides a new direction for the treatment of IIMT.

A Diagnosis of Gastric Inflammatory Myofibroblast Tumor: A Challenge Like No Other!

Inflammatory myofibroblastic tumors (IMTs) are mesenchymal tumors of intermediate malignant potential. Gastric IMTs are rare and commonly affect young adults. They are typically confused with gastrointestinal stromal tumors, inflammatory fibroid polyps, and leiomyosarcomas. The etiology of IMTs remains unclear, but is theorized to be due to hyperinflammatory response to chronic infections. We present a middle-aged woman found to have a gastric mass positive for Helicobacter pylori, underwent multiple endoscopies with endoscopic ultrasound, and a definitive diagnosis of gastric IMT was only made after a partial gastrectomy with immunohistochemistry negative for CD-117, S-100, ALK-1, and positive for vimentin and SMA.

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.

ALK-rearranged mesenchymal neoplasms: a clinicopathological and molecular study of eight additional cases of an emerging group of tyrosine kinase fusion mesenchymal tumours

AIMS

Mesenchymal neoplasms characterised by ALK fusions mainly include inflammatory myofibroblastic tumour (IMT) and epithelioid fibrous histiocytoma (EFH). Most recently, ALK-rearranged mesenchymal tumours that are not IMT or EFH have been reported. Our aim is to further characterise eight such neoplasms, with a detailed clinicopathological, immunohistochemical and molecular analysis.

METHODS

Clinicopathological features were assessed and partner agnostic targeted RNA-sequencing on clinically validated platforms was performed.

RESULTS

The patients consisted of seven males and one female with a median age of 47 years (28 -59 years). The tumours ranged in size from 2.0 to 10.0 cm (mean=3.0 cm) and involved superficial and deep soft tissue (n=6) and visceral locations (n=2). Of the seven patients with follow-up (9-130 months), two developed distant metastases and five had no disease recurrence or metastasis. The tumours demonstrated diverse architectures and variable cellularity and cellular morphologies. The main constitutive cells appeared in elongated spindled in three, primitive to ovoid in two and round to epithelioid in three cases. We expanded the histopathological spectrum to include mildly to moderately cellular spindled to stellate cells in a multinodular growth in a prominent myxoid and vascularised stroma (n=2). All tumours expressed ALK(D5F3); seven were positive for S100 protein and six were positive for CD34. By fluorescence in situ hybridisation, ALK rearrangement was identified in all eight tumours. ALK fusion partners were identified by RNA-sequencing in all cases, including previously reported: EML4 (n=3), DCTN (n=1), CLIP1 (n=1) and PLEKHH2 (n=1), and also two novel fusion partners: TKT (n=1) and MMP2 (n=1).

CONCLUSIONS

Our study expands the clinicopathological and molecular spectrum of ALK-rearranged mesenchymal neoplasms.

Inflammatory Myofibroblastic Tumor of the Sciatic Nerve Mimicking Lumbar Disc Herniation: A Diagnostic Challenge

Inflammatory myofibroblastic tumors (IMTs), which involve the proliferation of fibroblastic-myofibroblastic cells mixed with inflammatory infiltrates, are exceedingly rare in the extremities. There are no reported IMTs involving the sciatic nerve. This type of involvement may cause entrapment of the sciatic nerve, whose symptoms may mimic lumbar disc herniation (LDH), especially when it occurs in patients with lumbar degenerative disc disease. We describe the case of a 40-year-old male with lumbar degenerative disc disease accompanied by IMT involving the sciatic nerve whose symptoms mimicked LDH and posed a diagnostic challenge. We showed the course of the disease as well as the systematic imaging manifestations of IMTs involving the sciatic nerve and discussed their therapeutic management.

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.

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.

Multiple anaplastic lymphoma kinase-positive primary inflammatory myofibroblastic tumors with spontaneously expanding and shrinking nodules in both lungs: a case report

BACKGROUND

Inflammatory myofibroblastic tumors (IMTs) are uncommon neoplasms most prevalent in individuals under 40 years old and predominantly in the lungs. Despite their rarity, multiple anaplastic lymphoma kinase (ALK)-positive IMTs, especially those of various sizes, have not been widely reported. This report describes a case of multiple ALK-positive IMTs in the lungs, aiming to further our understanding of their behavior and management.

CASE PRESENTATION

Herein, we present the case of a 64-year-old woman who presented with an abnormal shadow on chest examination. Chest computed tomography revealed a main tumor in the right middle lobe and multiple irregularly shaped small nodules in both lungs. Thus, thoracoscopic wedge resection of the left lower lobe was performed for diagnosis. Pathological findings indicated smooth muscle proliferation without malignancy. IMT was diagnosed following thoracoscopic right middle lobectomy. Twenty months postoperatively, one residual nodule shrank, but another grew.

CONCLUSIONS

This is the first report of multiple ALK-positive IMTs in both lungs, highlighting the need for definitive diagnosis and treatment of IMTs based on surgical resection. Although caution is required in patients with lymph node metastases or distant metastases, careful follow-up is acceptable unless there is a tendency for nodules to increase in size on imaging.

Inflammatory myofibroblastic tumor of the cecum presenting as acute abdomen, a rare pathology with a rarer presentation

Inflammatory myofibroblastic tumor is an extremely rare neoplastic lesion with a predilection for aggressive local and recurrent behavior. The tumor tends to occur in the lungs of children and young adults, and although it can develop in older patients and other organs, this is extremely rare. Symptoms are nonspecific and depend on the location and size of the tumor. The gastrointestinal tract is rarely this mass's primary site of origin, and the cecum is an even rarer location. We present the case of an otherwise healthy 55-year-old female who presented with an acute abdomen and a mass in her abdomen; after successful surgery, she fully recovered. Inflammatory myofibroblastic tumor causing acute abdomen was the final diagnosis.

Update on immunohistochemistry in bone and soft tissue tumors: Cost-effectively replacing molecular testing with immunohistochemistry

Soft tissue tumors form part of a challenging domain in diagnostic pathology owing to their comparative rarity, astonishing histologic diversity, and overlap between entities. Many of these tumors are now known to be defined by highly recurrent, or, in some instances, unique molecular alterations. Insights from gene profiling continue to elucidate the wider molecular landscape of soft tissue tumors; many of these advances have been co-opted by immunohistochemistry (IHC) for diagnostic applications. There now exists a multitude of antibodies serving as surrogate markers of recurrent gene fusions, amplifications, and point mutations, which, in certain settings, can replace the need for more resource and time-intensive cytogenetic and molecular genetic analyses. IHC presents many advantages including rapid turnaround time, cost-effectiveness, and interpretative reproducibility. A sensible application of these immunohistochemical markers complemented by a working knowledge of the molecular pathogenesis of bone and soft tissue tumors permits accurate diagnosis in the majority of cases. In this review, we will outline some of these biomarkers while emphasizing molecular correlates and highlighting interpretative challenges and pitfalls.

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.

Non-gastrointestinal stromal tumor, mesenchymal neoplasms of the gastrointestinal tract: a review of tumor genetics, pathology, and cross-sectional imaging findings

There is a diverse group of non-gastrointestinal stromal tumor (GIST), mesenchymal neoplasms of the gastrointestinal (GI) tract that demonstrate characteristic pathology and histogenesis as well as variable imaging findings and biological behavior. Recent advancements in tumor genetics have unveiled specific abnormalities associated with certain tumors, influencing their molecular pathogenesis, biology, response to treatment, and prognosis. Notably, giant fibrovascular polyps of the esophagus, identified through MDM2 gene amplifications, are now classified as liposarcomas. Some tumors exhibit distinctive patterns of disease distribution. Glomus tumors and plexiform fibromyxomas exhibit a pronounced affinity for the gastric antrum. In contrast, smooth muscle tumors within the GI tract are predominantly found in the esophagus and colorectum, surpassing the incidence of GISTs in these locations. Surgical resection suffices for symptomatic benign tumors; multimodality treatment may be necessary for frank sarcomas. This article aims to elucidate the cross-sectional imaging findings associated with a wide spectrum of these tumors, providing insights that align with their histopathological features.

A diagnostically challenging case of inflammatory myofibroblastic tumor primary to the peritoneum

Introduction

Inflammatory myofibroblastic tumors are difficult to diagnose because of the lack of specific indicators. We describe a diagnostically challenging case of an inflammatory myofibroblastic tumor primary to the peritoneum.

Case presentation

The patient was a 25-year-old male who presented at our hospital with lower abdominal pain. Computed tomography revealed a mass lesion 80 mm in diameter just above the bladder. This was suspected to be a bleeding tumor of the urachus. Since malignancy could not be ruled out, surgery was planned. This revealed a fragile tumor arising from the peritoneum. Following its removal, the tumor was diagnosed by histopathological analysis as an inflammatory myofibroblastic tumor.

Conclusion

We describe a case of inflammatory myofibroblastic tumor primary to the peritoneum diagnosed by histopathology. Inflammatory myofibroblastic tumor should be considered in the differential diagnosis of abdominal wall and anterior bladder tumors.