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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.

Angiomyofibroblastoma and superficial myofibroblastoma are distinctive benign mesenchymal tumors occurring in the female lower genital tract. Despite their significant overlapping clinicopathologic features, including the presence of bland-looking spindle or oval cells with myofibroblastic or myoid differentiation, the tumors have been regarded as separate entities. Although subepithelial, hormone-sensitive mesenchymal cells of the female lower genital tract are considered as their potential common progenitor cells, their potential kinship or pathogenetic similarities remain elusive. Based on the identification of a novel RNA sequencing-based MTG1-CYP2E1 fusion transcript in an angiomyofibroblastoma index case, we investigated an additional ten samples of the tumor and its site-specific histological mimics, including eight superficial myofibroblastomas, four deep angiomyxomas, four cellular angiofibromas, three fibroepithelial stromal polyps, and eight non-site-specific mesenchymal tumors occurring in the female lower genital tract. Using reverse transcription-polymerase chain reaction, we showed that the MTG1-CYP2E1 fusion transcripts were consistently detectable in angiomyofibroblastomas (5/5, 100%) and often in superficial myofibroblastomas (3/5, 60%) but were not detected in the other examined site-specific or non-site-specific mesenchymal tumors. Our immunohistochemical experiments showed that CYP2E1, an isoenzyme belonging to the cytochrome P450 superfamily, exhibited increased positivity in tumors with MTG1-CYP2E1 than was observed in fusion-negative tumors (RR = 6.56, p = 0.001). The results of our study provide further evidence supporting the assertion that angiomyofibroblastoma and superficial myofibroblastoma represent phenotypic variants of site-specific mesenchymal tumors and share a common oncogenic mechanism.

Inflammatory myofibroblastic tumor (IMT) of the uterus is an uncommon mesenchymal neoplasm that frequently harbors ALK rearrangements. In this report, we describe the first uterine IMT with a FN1-ROS1 fusion, which occurred in a 43-year-old woman who presented with menorrhagia. Morphologically, the well-circumscribed 3 cm tumor was comprised of compact and myxoid foci of relatively bland spindle cells admixed with scattered chronic inflammatory cells limited to the myxoid areas. ROS1 showed moderate cytoplasmic granular staining in < 30% of cells in the myxoid foci, while ALK was negative. RNA sequencing detected a FN1-ROS1 rearrangement that fused FN1 exon 37 to ROS1 exon 34. Although non-ALK-rearranged uterine IMTs are exceedingly rare, this example highlights the importance of performing ROS1 immunohistochemistry and/or molecular analysis in ALK-negative uterine neoplasms morphologically compatible with IMT.

Background/aim Myofibroblastoma of the breast is a rare benign mesenchymal tumor whose morphology is similar to that of spindle-cell lipoma. The few hitherto genetically investigated mammary myofibroblastomas have been shown to have had loss of material from chromosome 13, changes that are also common in spindle-cell lipoma. Our aim was to add to the existing knowledge of genetic aberrations in mammary myofibroblastoma by investigating another such tumor. Materials and methods Cytogenetic and array comparative genome hybridization (aCGH) analyses were performed on a surgically removed mammary myofibroblastoma from a 76-year-old man. Results Short-term cultured cells from the tumor showed the karyotype 45,XY,-13[3]/44~45,idem,add(19)(q13)[cp2]. aCGH detected loss of one entire chromosome 13 and heterozygous loss from 19q between sub-band 19q13.12 and 19qter. Conclusion These findings add to the evidence that loss of 13q material is typical of mammary myofibroblastomas.

Inflammatory myofibroblastic tumor (IMT) is a rare borderline malignancy, usually treated with surgery only. Exceedingly rare cases of inoperable, recurrent, or metastatic IMTs pose a therapeutic challenge. We report successful treatment of a 7-year-old girl with an inoperable anaplastic lymphoma kinase (ALK)-negative IMT of the tongue. The patient underwent various anti-inflammatory (steroids, nonsteroidal anti-inflammatory drugs, clarithromycin) and antiproliferative (chemotherapy) therapies to enable tumor regression and complete resection. Ultimately, next-generation sequencing of the tumor revealed a TFG-ROS-1 translocation, allowing for an off-label targeted therapy with crizotinib. Crizotinib treatment caused slight tumor regression but evident change of its structure, allowing for complete non-mutilating resection. Two histopathology examinations revealed complete disappearance of neoplastic cells following therapy. The patient remains disease-free 22 months after the delayed surgery. In children with inoperable ALK-negative IMTs, molecular testing must be performed to identify other targetable oncogenic fusions, including TFG-ROS1.

Inflammatory myofibroblastic tumor (IMT) is a distinctive fibroblastic and myofibroblastic spindle cell neoplasm with an accompanying inflammatory cell infiltrate and frequent receptor tyrosine kinase activation at the molecular level. The tumor may recur and rarely metastasizes. IMT is rare in the head and neck region, and limited information is available about its clinicopathologic and molecular characteristics in these subsites. Therefore, we analyzed a cohort of head and neck IMTs through a multi-institutional approach. Fourteen cases were included in the provisional cohort, but 1 was excluded after molecular analysis prompted reclassification. Patients in the final cohort included 7 males and 6 females, with a mean age of 26.5 years. Tumors were located in the larynx (n=7), oral cavity (n=3), pharynx (n=2), and mastoid (n=1). Histologically, all tumors showed neoplastic spindle cells in storiform to fascicular patterns with associated chronic inflammation, but the morphologic spectrum was wide, as is characteristic of IMT in other sites. An underlying fusion gene event was identified in 92% (n=11/12) of cases and an additional case was ALK-positive by IHC but could not be evaluated molecularly. ALK represented the driver in all but 1 case. Rearrangement of ALK, fused with the TIMP3 gene (n=6) was most commonly detected, followed by 1 case each of the following fusion gene partnerships: TPM3-ALK, KIF5B-ALK, CARS-ALK, THBS1-ALK, and a novel alteration, SLC12A2-ROS1. The excluded case was reclassified as spindle cell rhabdomyosarcoma after detection of a FUS-TFCP2 rearrangement and retrospective immunohistochemical confirmation of rhabdomyoblastic differentiation, illustrating an important diagnostic pitfall. Two IMT patients received targeted therapy with crizotinib, with a demonstrated radiographic response. One tumor recurred but none metastasized. These results add to the growing body of evidence that kinase fusions can be identified in the majority of IMTs and that molecular analysis can lead to increased diagnostic accuracy and broadened therapeutic options for patients.

Objectives Benign tumors with skeletal muscle differentiation are rare and their characterization in the literature is limited. We present a series of twelve pediatric benign tumors with rhabdomyomatous differentiation including seven rhabdomyomatous mesenchymal hamartomas, four fetal rhabdomyomas, and one benign triton tumor, analyzing myogenic markers as well as clinicopathologic and molecular features. A review of the literature was also performed with an emphasis on myogenic marker expression and correlation with molecular features. Methods and Results Cases obtained from three tertiary pediatric hospitals were retrospectively reviewed. Eleven of twelve cases expressed myogenin in rare to greater than 15% of cells. Five of nine cases had rare to 70–80% of cells positive for MyoD1. One fetal rhabdomyoma demonstrated homozygous deletions in ZEB2. The benign triton tumor harbored a CTNNB1 mutation. Review of the literature identified 160 pediatric benign tumors with skeletal muscle differentiation of which 9 reported myogenin positivity. Conclusions Myogenin and MyoD1 may be variably expressed in benign lesions with skeletal muscle differentiation. Recognition of key morphologic features remains critical to diagnose these lesions and, in rhabdomyoma, to exclude malignancy. Our series expands the knowledge of the relationship between rhabdomyoma and rhabdomyosarcoma (RMS) by identifying a shared molecular alteration in ZEB2.

Objective: this study aimed to translate and cross-culturally adapt the musculoskeletal tumor society (MSTS) scoring system into Turkish and to determine the reliability and validity of the translated version for the functional evaluation of patients with musculoskeletal tumors. Methods: a total of 36 patients (16 women, 20 men; mean age=36.6; age range=13-75 years) who underwent limb-salvage surgery owing to benign aggressive or malignant musculoskeletal tumors were included in the study. Translation and back translations of the MSTS were performed according to the published guidelines. Short form (SF) 36 physical component, Western Ontario and McMaster Universities Arthritis Index (WOMAC), disabilities of the arm, shoulder, and hand (DASH), and range of motion scale (ROMS) that were previously analyzed for Turkish validation were used for validity. Reliability of MSTS Turkish version was evaluated by calculating test-retest reliability and internal consistency. Intraclass correlation coefficient (ICC) was used to evaluate the inter-observer consistency and test-retest reliability. Alpha coefficient (Cronbach's alpha) was used to evaluate the internal consistency. Results: it was observed that total MSTS score has a strong negative correlation with DASH (r=-0.689; p, NA

Uterine epithelioid and myxoid leiomyosarcomas and inflammatory myofibroblastic tumors are rare mesenchymal neoplasms. Next-generation sequencing recently detected novel PGR fusions in uterine epithelioid leiomyosarcomas that demonstrate characteristic rhabdoid and spindled morphology. PLAG1 gene fusions have also been identified in a subset of myxoid leiomyosarcomas and are associated with PLAG1 overexpression. ALK rearrangements underpin the vast majority of uterine inflammatory myofibroblastic tumors, which demonstrate morphologic, and immunohistochemical features similar to those of inflammatory myofibroblastic tumors elsewhere. This review summarizes the morphologic, immunophenotypic, and molecular genetic features of PGR fusion-positive epithelioid leiomyosarcoma, PLAG1 fusion-positive myxoid leiomyosarcoma, and inflammatory myofibroblastic tumors of the uterus.

Inflammatory myofibroblastic tumors are rare tumors with an ALK (anaplastic lymphoma kinase) gene rearrangement in up to 65% of all cases. In our patient, the tumor was not primary resectable due to its extension. Under neoadjuvant treatment with the first generation ALK inhibitor crizotinib no tumor response was seen, but the following therapy with the next generation ALK inhibitor lorlatinib led to a rapid and deep response, enabling a complete tumor resection by partial cystectomy. Our case indicates that ALK positive inflammatory myofibroblastic tumors which do not respond to ALK inhibition with crizotinib can be successfully treated with newer agents.

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.

Intranodal palisaded myofibroblastoma (IPM) is a rare, benign mesenchymal neoplasm of the lymph nodes with a broad differential diagnosis. We report a case of an 82-year-old woman presenting with a slow growing, right inguinal mass. The tumor arose as a circumscribed neoplasm inside a lymph node and consisted of bland spindle cells with nuclear palisading and intervening areas of amianthoid-like fibers among interstitial hemorrhage and hemosiderin-laden histiocytes in the stroma, typical histomorphological characteristics of IPM. Immunohistochemically, the neoplastic cells were positive for vimentin, smooth muscle actin (SMA), β-catenin, cyclin D1 and discovered on gastrointestinal stromal tumor (GIST) 1 (DOG1) immunostainings. A literature review and differential diagnosis of IPM are discussed. To the best of our knowledge, this is the first case of DOG1 immunoexpression in a case of IPM.

淋巴结内栅栏状肌纤维母细胞瘤是一种罕见的发生于淋巴结内的良性间叶源性肿瘤。该病主要累及45~55岁的中年人，病变主要累及腹股沟淋巴结。本文报道1例65岁老年女性患者，镜下表现显示梭形细胞栅栏状排列伴间质内出血及石棉样纤维形成，免疫组织化学平滑肌肌动蛋白、肌动蛋白、波形蛋白、cyclin D1、β-catenin阳性表达。该病罕见，需要加强对本病的认识，避免不必要的误诊和过度治疗。.

Inflammatory myofibroblastic tumors (IMTs) are mesenchymal solid tumors, in which anaplastic lymphoma kinase (ALK) gene rearrangement might be detected. A 48-year-old female presented with IMT of lung, treated with surgery. After a 39-month disease-free survival metastatic recurrence was occurred involving soft tissues both infra- and supradiaphragmatic regions. The biopsies obtained from metastatic regions confirmed the recurrence with ALK rearrangement in immunohistochemistry. Initial partial response observed early in treatment course remained as a stable disease with crizotinib treatment. Although an excellent outcome with overall survival of 57 months was observed in our case, there is not enough information about survivals with crizotinib and the treatment options beyond progression. Therefore, every individual case has a unique value paving the way for more effective treatment.

An inflammatory myofibroblastic tumor (IMT) is a rare invasive soft tissue mass with intramuscular penetration that is primarily treated via a surgical procedure. However, with unclear boundaries and a high rate of relapse, there is no standard treatment for recurrence or unresectable tumors. It is noteworthy that approximately half of IMTs harbor genetic rearrangements of the anaplastic lymphoma kinase (ALK). ALK inhibitors have been used successfully in the treatment of IMTs with a variety of ALK fusions. Here, we present a case of a 15-year-old patient with IMT around the hip. Next-generation sequencing (NGS) revealed an LRRFIP1-ALK fusion, which has not yet been reported in the literature. Crizotinib, an ALK inhibitor, was effective in the treatment of this patient, indicating that ALK inhibitors may be effective for IMT with LRRFIP1-ALK fusions. This report expands the list of gene fusions in IMTs and highlights a new target for treatment.

Mammary-type myofibroblastoma (MFB) is a benign spindle cell tumor of the breast and soft tissue characterized by 13q14 alterations leading to loss of Rb-1 protein expression, a feature shared among spindle cell lipoma and cellular angiofibroma. In this article, we present a novel case of MFB arising in the left breast of a 70-year old man that microscopically showed an abrupt transition from classic MFB morphology to an area with cytologic atypia and mitotic activity, akin to sarcomatous transformation described in cellular angiofibromas. A thorough workup of the molecular underpinnings of both components using chromosomal microarray and next-generation sequencing platforms supported a clonal relationship. Nearly identical copy number changes, including a single copy loss of 13q14, were found in both components; in addition, the sarcomatous component harbored biallelic TP53 alterations. It is important for pathologists to recognize that sarcomatous features can occur in mammary-type MFB to arrive at the correct diagnosis.

A 34-year-old Chinese woman found a lump in her left leg for more than 3 weeks without any discomfort. Grossly, the tumor was relatively well delineated with focal infiltration. Histopathologic evaluation showed a compact fascicular spindle cell proliferation with variable myxoid and collagenous stroma and scattered inflammatory infiltrate. Immunohistochemically, the tumor cells showed positive expression of ALKD5F3 and SMA and negative expression of CD34, desmin, and cytokeretin. Fluorescence in situ hybridization analysis of the ALK locus showed break-apart signals in 20% of tumor cells, and DNA sequencing discovered a novel CLIP2-ALK fusion gene. The lesion was diagnosed as an inflammatory myofibroblastic tumor (IMT). To the best of our knowledge, this is the first case with CLIP2-ALK gene fusion in the somatic soft tissue IMTs.

Inflammatory myofibroblastic tumor (IMT) is a non-neoplastic benign lesion comprising various inflammatory cells, including myofibroblasts and vascular tissues. It is a rare tumor that sometimes shows similar signs and progression as malignant tumors. The anatomical sites of IMTs include the lungs, liver, orbit, skin, mesentery, and maxillary sinus, but they rarely occur in the limb musculoskeletal system. To our knowledge, no case of neurological symptoms caused by the tumor in the triceps brachii muscle has been reported. In this article, we report the case of a 42-year-old male patient with an IMT that grew rapidly in the triceps brachii muscle and consequently caused symptoms of ulnar nerve lesion owing to its increasing size. The patient showed no ulnar nerve lesion symptoms after undergoing wide excision and was diagnosed with anaplastic lymphoma receptor tyrosine kinase- negative IMT.

Analysis of surgical management and survival of pediatric patients with gastric tumors treated at our institution. A retrospective study of patients with primary gastric tumors treated between 1993 and 2018 was conducted. Eight patients, five girls and three boys, were diagnosed with gastric tumors at an average age of 10.4 years (1 day–15.4 years). Surgical management included Billroth type I procedure in five and tumor excision in three patients. Histology revealed gastrointestinal stromal tumor (GIST) in four patients and one of each of schwannoma, myofibroblastic tumor, hamartoma and teratoma. Microscopically clear margins were reported in six patients. Repeated local recurrence occurred in three patients (2 × GIST, 1 × myofibroblastic tumors) who consequently underwent three, four and six reoperations. One of these patients had liver metastases, which were managed with ligation of the hepatic arteries. This patient was also diagnosed with a lung hamartoma, which was treated with a lobectomy. Survival rate was 100% with a median follow-up of 8.6 years (7 months–25.5 years). Gastric tumors are rare in children and represent a management challenge. Repeated recurrence of GISTs and myofibroblastic tumors remains frequent even after complete resection and may necessitate multiple surgeries, therefore patients require a lifelong follow-up.

Myofibroblastic tumors are rare lesions which can affect any part of the body. Although benign, their mass effect causes symptoms that can become life-threatening. Supraglottic laryngeal involvement is extremely rare, with only 4 cases described in the English literature. Because the pathophysiology is unknown and the incidence is so low, there is no standardized therapeutic management, although for laryngeal tumors surgery has traditionally been the preferred initial option. Another less common option is intravenous and oral corticosteroid therapy, but this is usually reserved for myofibroblastic tumors in other head and neck sites that are more difficult to access surgically, or patients who cannot undergo surgery. These lesions have a very high tendency to recur, and morbidity rates are therefore also high. We present a case of supraglottic myofibroblastic tumor in which we elected high-dose corticosteroid therapy as the only form of treatment. With this new therapeutic approach, we avoided the undesirable effects of the usual type of surgery. At the 12-month follow-up, the patient is in complete remission.

As inflammatory myofibroblastic tumors (IMTs) have become more widely recognized in the female genital tract, an intriguing subset of uterine tumors associated with pregnancy has emerged. Whether uterine IMTs occurring in the setting of pregnancy are clinically or biologically distinct from other uterine IMTs is unknown. Furthermore, little is known about the perinatal factors that may influence the development of these tumors. Here, we report the largest case series of 8 pregnancy-associated IMTs. All pregnancy-associated IMTs in this series occurred in association with pregnancy complications, including abnormal implantation (n=1), gestational diabetes (n=2), preeclampsia and/or HELLP syndrome (n=2), antiphospholipid syndrome (n=1), premature rupture of membranes (n=1), and hepatitis B (n=1). Notably, all IMTs were expelled at the time of delivery or immediately postpartum and were either adherent to the placenta or presented as separate, detached tissue. Tumors ranged from 2.0 to 6.0 cm (median, 3.9 cm), were well-circumscribed and showed classic histologic features of IMTs, including myxoid stroma and a lymphoplasmacytic infiltrate. Seven of 8 cases were positive by ALK immunohistochemistry and confirmed to have an ALK gene rearrangement by fluorescent in situ hybridization and RNA sequencing. The ALK-rearranged IMTs were found to be particularly enriched for TIMP3-ALK (n=5) and THBS1-ALK (n=2) fusions. The single case that was negative for an ALK rearrangement exhibited the classic morphology of an IMT. None of the 4 cases with available clinical follow-up recurred. The clinicopathologic features of pregnancy-associated IMTs in this series in conjunction with those reported in the literature suggests that these may be transient tumors that develop during pregnancy and shed at parturition; they appear to have a relatively indolent clinical course and favorable outcome, although studies with a longer duration of follow-up are still required.

Introduction Fibroblastic/myofibroblastic tumors constitute 12% of all pediatric soft tissue tumors with the majority of them belonging to the benign and intermediate prognostic categories. They are often misdiagnosed owing to their variable clinical presentation and unusual microscopic features. The diagnosis, specially cytological diagnosis of benign and intermediate categories is difficult due to paucity of cellular component and increased amount of extracellular matrix as compared to malignant ones. We hereby discuss the Fine needle aspiration cytology (FNAC) findings of non-malignant fibroblastic/myofibroblastic lesion in the pediatric age group encountered at our institute. Methods All the benign and intermediate fibroblastic/myofibroblastic/fibroadipocytic lesions (age 0-12 years) diagnosed on FNAC over a period of 3½ years (Jan 2016- July 2019), with availability of corresponding histopathology were included in the study. Results A total of seven pediatric benign and intermediate fibroblastic/myofibroblastic lesions with histopathological confirmation were identified which included Infantile digital fibromatosis (IDF) (n = 2), Lipofibromatosis (n = 1), Fibrous hamartoma of infancy (FHI) (n = 1), Fibromatosis colli (FC) (n = 2) and myofibroma/myofibromatosis (n = 1). FNAC smears were mainly paucicellular with presence of benign spindle shaped cells in a collagenous stroma common to almost all the cases. A few additional findings such as degenerated skeletal muscle fibres, muscle giant cells and mature adipose tissue were also present in some cases. Conclusion Fibroblastic/myofibroblastic tumors although uncommon, form an important category that must be considered in the differential diagnosis of pediatric soft tissue tumors. FNAC cytology features when assessed in a proper clinical setting (specially the age and site of presentation) are helpful in suggesting probable preoperative diagnosis in these lesions.

Inflammatory myofibroblastic tumor (IMT) is a neoplasm of intermediate biological potential. Few cases of spermatic cord IMT have been reported in the literature. Inflammatory myofibroblastic tumor is a consequence of the proliferation of fibroblasts and inflammatory cells. Despite its benign nature, the tumor often clinically mimics intrascrotal malignancy and usually remains undiagnosed preoperatively. The diagnosis of spermatic IMT is difficult preoperatively due to the non-specific findings. Therefore, if testicular tumors cannot be precisely excluded, radical orchiectomy should be performed for the diagnosis and treatment. However, it mainly occurs in children and young adults; spermatic IMT may also be seen among elderly men. Here, we report two cases of inflammatory myofibroblastic tumor involving the spermatic cord. SIMILAR CASES PUBLISHED: There are seven cases entitled “inflammatory myofibroblastic tumor of spermatic cord” in the literature. In our study we present two cases that had a spermatic cord IMT. Furthermore, one of these cases was 82 years of age and is the oldest patient presented in the literature.

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 34βE12, 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.

According to the WHO classification, mesenchymal tumors of the kidney are divided into mesenchymal tumors occurring mainly in adults and children. Accumulating evidence suggests that renal mesenchymal tumors represent a group of histologically heterogeneous diseases. We are reporting the case of a 58-year-old man with a history of nephron-sparing surgery due to renal cell carcinoma in 2014 in his left kidney. He was urgently admitted to the hospital due to left-sided nephrotoxic and anuria. Computed tomography (CT) imaging was performed and revealed irregular tumor mass. He underwent left-sided nephrectomy. Microscopic appearance and immunoprofile allowed to diagnose the tumor as an inflammatory myofibroblastic tumor (IMT) of the kidney. According to the 2016 World Health Organization (WHO) classification of tumors of the urinary system and male genital organs, IMT is a benign mesenchymal tumor with malignant potential. Typical locations are the liver and biliary tract, lung, and gastrointestinal tract. In the urogenital system, IMT occurs mainly in the bladder. So far, 48 cases have been reported in the kidney.

Inflammatory myofibroblastoma (IMT) is a rare solid tumor, and its etiology and pathogenesis are unclear. Crohn's disease is a non-specific intestinal inflammatory disease. The clinical manifestations, laboratory examinations, and imaging examinations of IMT are not specific, making diagnosis difficult. A case of Crohn's disease combined with IMT of abdominal wall was admitted to the Department of Gastroenterology at the Third Xiangya Hospital, Central South University, on Nov. 21, 2017. This patient was admitted to our hospital because of repeated right lower abdominal pain for 4 years. A 6 cm×5 cm mass was palpated in the right lower abdomen. After completing the transanal double-balloon enteroscopy and computed tomographic enterography for the small intestinal, the cause was still unidentified. The patient underwent surgery due to an abdominal wall mass with intestinal fistula on Sept. 12, 2018 and recovered well currently. According to histopathology and immunohistochemistry, he was diagnosed with Crohn's disease combined with IMT. Up to July 2020, the patients still took azathioprine regularly, without abdominal pain, abdominal distension, and other discomfort, and the quality of his life was good.炎性肌纤维母细胞瘤(inflammatory myofibroblastoma，IMT)是一种罕见的实体瘤，其病因和发病机制尚不清楚。克罗恩病(Crohn's disease)是一种非特异性肠道炎症性疾病。IMT的临床表现、实验室检查及影像学检查均无明显特异性，诊断困难。国内外暂无克罗恩病与IMT在腹壁的病例报道。中南大学湘雅三医院消化内科于2017年11月21日收治1例克罗恩病合并腹壁IMT的患者。患者反复右下腹腹痛4年，体格检查右下腹可触及一6 cm×5 cm大小包块，完善经肛双气囊小肠镜、小肠CT造影等检查未明确病因，2018年9月12日患者因腹壁包块并发肠瘘行手术治疗，术后恢复良好，经组织病理及免疫组织化学检测确诊为克罗恩病合并腹壁IMT。随访至2020年7月，患者仍规律服用硫唑嘌呤，未出现腹痛、腹胀等不适，生活质量良好。.

Background Crizotinib is a first-generation tyrosine kinase inhibitor used for anaplastic lymphoma kinase (ALK) positive cancers. Simple and complex renal cyst formation is a rare complication of crizotinib use that has been reported previously in the adult population. Case We report a case of a right renal mass in a 17-year-old with ALK-positive epithelioid inflammatory myofibroblastic sarcoma treated with Crizotinib. After cessation of Crizotinib and initiating Alectenib, a second generation ALK inhibitor, the mass decreased in size and the patient remained asymptomatic without evidence of recurrence at three months of follow-up.

Patient: Male, 48-year-old Final Diagnosis: Intranodal palisaded myofibroblastoma Symptoms: Inguinal lump Medication: — Clinical Procedure: Lumpectomy Specialty: Pathology • Surgery Objective: Rare disease 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 β-catenin gene with subsequent abnormal expression of β-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 β-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 β-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.

本文报道1例发生于儿童原发性喉部巨大炎性肌纤维母细胞瘤病例（inflammatory myofibroblastic tumor，IMT）。患儿女，10岁，因“睡眠打鼾伴呼吸不畅3个月”于2018年10月31日至南京市儿童医院就诊。术前行喉镜及CT检查示喉部左侧类圆形孤立肿物，入院诊断为喉部肿物。入院后，患儿在全身麻醉下行支撑喉镜喉肿物切除术，肿物为2 cm×2 cm×1 cm大小质中肿块，术后病理诊断为IMT。术后出院随访至今未见复发，预后良好。.

Inflammatory myofibroblastic tumours (IMTs) are rare tumours with unpredictable biological behaviour ranging from benign to locally invasive and rarely, distant metastasis. While neurofibromatosis type 1 (NF1) may manifest with gastrointestinal soft tissue tumours, this is the first report in the literature that describes an IMT occurring in a NF1 patient who presented with intestinal obstruction. Our patient presented with intestinal obstruction secondary to an obstructing terminal ileum mesenteric tumour. En bloc bowel resection was performed, with histology revealing an IMT and an adjacent neurofibroma. The resection margins were clear and the patient was free of recurrence at six months.

To describe the clinicopathological features and differential diagnoses of 15 cases of superficial myofibroblastoma, a rare mesenchymal tumor involving the lower female genital tract.The clinicopathological data and immunohistochemical findings were retrospectively analyzed in 15 cases of superficial myofibroblastoma. Meanwhile, a systematic literature review was conducted.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.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.

Východiska: Zanětlivý myofibroblastický nador jicnu je vzacna mezenchymalni neoplazie středně maligniho potencialu. Přestože se nejcastěji vyskytuje v plicich, může se objevit v mnoha jiných anatomických lokalizacich vc. gastrointestinalniho traktu, avsak postiženi jicnu je velmi vzacne. Myofibroblastický nador jicnu se nejcastěji manifestuje u děti a mladých dospělých. Zakladnim terapeutickým postupem je chirurgicka resekce. Kazuistika: V teto kazuistice prezentujeme připad 13leteho chlapce s myofibroblastickým nadorem jicnu, který podstoupil chirurgickou resekci v roce 2013 a od te doby je v trvale remisi. Zavěr: Chirurgicka lecba je nejvice upřednostňovanou metodou lecby. V připadě kompletni resekce je riziko recidivy nizke. Nicmeně každeho pacienta po resekci je třeba peclivě dispenzarizovat.

Inflammatory myofibroblastic tumor (IMT) is a rare, mesenchymal tumor that has an increased incidence in childhood. Tumors are usually isolated to the chest, abdomen, and retroperitoneum, but metastatic presentations can be seen. Presenting symptoms are nonspecific and include fever, weight loss, pain, shortness of breath, and cough. Approximately 85% of IMTs harbor actionable kinase fusions. The diagnosis can be delayed because of overlapping features with inflammatory disorders, such as elevated inflammatory markers, increased immunoglobin G levels, fever, weight loss, and morphologic similarity with nonmalignant conditions. We present a girl aged 11 years with a TFG-ROS1 fusion–positive tumor of the lung that was initially diagnosed as an immunoglobin G4–related inflammatory pseudotumor. She underwent complete left-sided pneumonectomy and later recurred with widely metastatic disease. We then report the case of a boy aged 9 years with widely metastatic TFG-ROS1 fusion–positive IMT with rapid molecular diagnosis. In both children, there was an excellent response to oral targeted therapy. These cases reveal that rapid molecular testing of inflammatory tumors is not only important for diagnosis but also reveals therapeutic opportunities. Targeted inhibitors produce significant radiologic responses, enabling potentially curative treatment approaches for metastatic ROS1 fusion IMT with previously limited treatment options. Primary care pediatricians and pediatric subspecialists have a crucial role in the early consultation of a pediatric oncology center experienced in molecular diagnostics to facilitate a comprehensive evaluation for children with inflammatory tumors.

Plaque-like myofibroblastic tumour (PLMT) is a rare skin condition which presents in childhood and infancy as a nodular fibrous plaque. Including our case, there are currently only 14 cases reported in the literature. Although it represents a well-defined clinicopathological diagnosis, there is significant under-reporting of this condition secondary to under-recognition and potential misdiagnosis as dermatofibroma.

Purpose: European Organisation for Research and Treatment of Cancer (EORTC) 90101 (CREATE) was a prospective, multicentric, non-randomised, open-label phase II bas-ket trial to assess the efficacy and safety of crizotinib in patients with different types of cancers, including advanced inflammatory myofibroblastic tumour (IMT) with or without anaplastic lymphoma kinase (ALK) rearrangements. Here, we report updated results with long-term follow-up. Patients/methods: After central reference pathology, eligible ALK-positive and ALK-negative patients with advanced/metastatic IMT deemed incurable with surgery, radiotherapy or sys-temic therapy received oral crizotinib 250 mg twice daily. The ALK status was assessed cen-trally using immunohistochemistry and fluorescence in situ hybridisation. The primary end-point was the proportion of patients who achieved an objective response (i.e. complete or par-tial response). If >6 ALK-positive patients achieved a confirmed response, the trial would be deemed successful. Results: At data cut-off on 28th January 2021, we performed the final analysis of this trial. Of the 20 eligible and treated patients (19 of whom were evaluable for efficacy), with a median follow-up of 50 months, five were still on crizotinib treatment (4/12 ALK-positive and 1/8 ALK-negative patients). The updated objective response rate (ORR) was 66.7% (95% confi-dence interval [CI] 34.9-90.1%) in ALK-positive patients and 14.3% (95% CI 0.0-57.9%) in ALK-negative patients. In the ALK-positive and ALK-negative patients, the median progression-free survival was 18.0 months (95% CI 4.0-NE) and 14.3 months (95% CI 1.2-31.1), respectively; 3-year overall survival rates were 83.3% (95% CI 48.2-95.6) and 34.3% (95% CI 4.8-68.5). Safety results were consistent with previously reported data. Conclusion: These updated results confirm previous findings that crizotinib is effective, with durable responses, in patients with locally advanced or metastatic ALK-positive IMT. With further follow-up after the original primary analysis, the ORR increased, as patients derived long-term benefit and some responses converted from stable disease to partial responses. Clinical trial number: EORTC 90101, NCT01524926. 2021 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).