Myofibroblastic Tumor Research Articles

Chapter 13: 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.

A Skin Inflammatory Myofibroblastic Tumor Penetrates Through Skull To The Dura: A Case Report

Abstract Introduction/Objective Inflammatory myofibroblastic tumor (IMT) is currently accepted to be a true neoplasm with a wide spectrum of biological behavior, varying from benign lesions to the rare tumors which are multifocal and prone to recurrence. IMT is characterized by a proliferation of myofibroblastic spindle cells with an inflammatory infiltrate. It was first described in the lung and later on reported in various sites such as stomach, intestine, spleen, bone. Here we report a rare IMT case in that the tumor penetrates through skull and extends to the dura. Methods/Case Report A 29-year-old female presented with a slowly progressive upper head scalp mass of one-year duration. Magnetic resonance imaging showed a soft tissue mass that extended through the skull and into the dura. Patient denies headache, syncopal episodes, neck pain, back pain, radicular symptoms, weakness, ataxia, nausea, vomiting, bladder or bowel incontinence, saddle anesthesia, or changes from baseline hearing, vision, or speech. Grossly, serial sectioning of the scalp skin specimen revealed a well-circumscribed mass lesion with white, firm, and homogeneous cut surface, with no hemorrhage or necrosis identified. The lesion measured 7.0 x 6.5 x 1.7 cm in greatest dimension. The lesion involved the deep margin and extended to the skull and dura. On histopathological examination, the lesion was composed of variable admixture of spindle cells with eosinophilic cytoplasm and inflammatory cells comprising of plasma cells and lymphocytes. The spindle cells were positive for smooth muscle actin, CD10 (partial), and negative for AE1/AE3, ALK–1, CD34, CD68, CD117, Desmin, Myogenin, p53, S-100, and SOX-10. The Ki-67 showed a spindle cell proliferation index at about 2%. The patient successfully went through surgery and was followed up without complications. Results (if a Case Study enter NA) NA Conclusion Our case showed a rare IMT case harboring histologically benign features like low cellularity, minimal nuclear atypia, and low proliferative index, but demonstrating locally very aggressive biological behaviors. Complete surgical resection and close follow up are suggested to avoid recurrence. Further studies are needed in this field to design in-depth investigation for accurate diagnosis and better clinical outcomes.

Mesenchymal and Non-meningothelial Tumors Involving the Central Nervous System

In the World Health Organization Classification of Brain Tumors Fifth Edition, mesenchymal non-meningothelial tumors involving the central nervous system are divided into three major categories: soft tissue tumors, chondro-osseous tumors, and notochordal tumors. Soft tissue tumors are classified into four groups: fibroblastic and myofibroblastic tumors, vascular tumors, skeletal muscle tumors, and tumors of uncertain differentiation. This article will focus on solitary fibrous tumors(SFTs), which are frequently encountered clinically and continue to undergo classification revisions in the 5th edition, and outline the three newly added histological diagnoses. Although SFTs and hemangiopericytomas occur throughout the body, including the central nervous system, nomenclatures have been different between the classifications of "Tumours of Soft Tissue and Bone" and "Tumours of the Central Nervous System." The latest nomenclature is "SFT" in accordance with the nomenclature of bone and soft-tissue tumors. In addition, three new diagnoses, which are intracranial mesenchymal tumor FET-CREB fusion-positive, CIC-rearranged sarcoma, and primary intracranial sarcoma DICER1-mutant, have been defined based on genetic abnormalities in tumors of uncertain differentiation.

Sarcoma Research with Cancer Registry Data: Data and Peculiarities of Germany in the Light of Other Countries

Introduction: Sarcomas are documented in population-based and in clinic-associated databases. This study evaluated the status quo regarding the potential and obstacles of cancer registry-based research on sarcomas exemplified by Germany in comparison to similar databases in the US and Europe. Completeness and quality of data are discussed based on statistical analyses of a pooled data set established for the German Cancer Congress 2020. Methods: We analyzed data derived from 16 German institutions (federal state cancer registries and some facility-based registries). Malignant sarcomas in adults diagnosed between 2000 and 2018 with information on histology were grouped according to the WHO classification of soft tissue and bone tumors. Descriptive analyses of the study population regarding the distribution of age, sex, histology, localization of primary tumors, and metastases were performed. Survival for the ten most frequent histological groups and UICC stages was evaluated according to Kaplan-Meier and Cox regression. Time interval between surgery and subsequent radiation was calculated. Results: The initial data set contained 35,091 sarcomas. After several steps of data cleaning, 28,311 patients with known sex and unambiguous assignment to a histological subgroup remained (13,682 women and 14,629 men). Between 40 and 54 years, women were more likely to develop sarcomas, whereas in the older age groups more men were affected. Gastrointestinal stromal tumors, fibroblastic, and myofibroblastic tumors, smooth muscle tumors (mostly non-uterine leiomyosarcomas), and adipocytic tumors represented 48% of all sarcomas. Preferential sites for fibrosarcomas were the limbs, the trunk, and the head and neck region. The liposarcoma occurred most frequently on the trunk and limbs. Distant primary metastases were mostly located in the lung (43%), followed by the liver (14%), and bones (13%). Vascular and smooth muscle tumors showed the worst survival prognosis (5-year survival: approx. 15%, median survival approx. 8–16 months), whereas in low stages, the probability of survival of many sarcoma patients was beyond 5 years. Adjuvant radiotherapy was applied within 90 days in 71% of patients (n = 2,534). Conclusion: Our results correspond to the data from the literature. However, a lack of data quality and completeness hampers further meaningful analyses, especially nonspecific or missing information about morphology and stage. Compared to some other countries, a comprehensive database is presently missing in Germany. However, currently, there are important efforts and legislative initiatives to create a comprehensive database on a national level within the near future.

Parotid's Intranodal Palisaded Myofibroblastoma: A Very Rare Tumour.

Intranodal palisaded myofibroblastoma is a rare benign tumor of the lymph nodes, that arises from smooth muscle cells or myofibroblast, chiefly in the inguinal lymph nodes. Intranodal palisaded myofibroblastoma of the parotid gland is exceedingly scarce, even more, its recurrent characteristic; which underlines the grave importance of a long, strict monitoring and surveillance plan. Alongside these salient points in this unusual case, we also aim to highlight the peculiar difficulties inevitably faced, given the unfortunate lack of typical pathognomonic clinical and radiological features. We therefore, report a rare case of recurrent intranodal palisaded myofibroblastoma, arising in the felt parotid gland in a 53-year-old male patient, diagnosed by anatomopathological and immunopathological analysis. Described as benign tumor intranodal palisaded myofibroblastoma is a scarce myofibroblastic neoplasm of the lymph nodes. Histological and immunopathological features represent the determining factors for the diagnosis, of this favorable prognosis tumor.

Fibroma of tendon sheath: a clinicopathological and genetic analysis of 134 cases

Objective: To investigate the clinicopathological features, immunophenotypes and molecular genetics of fibroma of tendon sheath (FTS). Methods: One hundred and thirty-four cases of FTS or tenosynovial fibroma diagnosed in the Department of Pathology, West China Hospital, Sichuan University, Chengdu, China from January 2008 to April 2019 were selected. The clinical and histologic features of these cases were retrospectively reviewed. Immunohistochemistry, fluorescence in situ hybridization (FISH) and reverse transcription-polymerase chain reaction (RT-PCR) were performed on the above cases. Results: There were a total of 134 cases of FTS, including 67 males and 67 females. The patients' median age was 38 years (ranged from 2 to 85 years). The median tumor size was 1.8 cm (ranged from 0.1 to 6.8 cm). The most common site was the upper extremity (76/134, 57%). Follow-up data was available in 28 cases and there was no detectable recurrence. Classic FTS (114 cases) were well-defined and hypocellular. A few spindle-shaped fibroblasts were scattered in the dense collagenous sclerotic stroma. Characteristically elongated slit-like spaces or thin-walled vessels were observed. Most of cellular FTSs (20 cases) were well-defined and the area with increased cellularity of the spindle cells coexisted with classic FTS. There were occasional mitotic figures, but no atypical mitotic figures. Immunohistochemistry was performed in 8 cases of classic FTS and most cases were positive for SMA (5/8). Immunohistochemistry was also performed in 13 cases of cellular FTS and showed 100% positive rate for SMA. FISH was conducted on 20 cases of cellular FTS and 32 cases of classical FTS. USP6 gene rearrangement was found in 11/20 of cellular FTS. Among 12 cases of CFTS with nodular fasciitis (NF)-like morphological feature, 7 cases showed USP6 gene rearrangement. The rearrangement proportion of USP6 gene in cellular FTS without NF-like morphological features was 4/8. By contrast, 3% (1/32) of the classic FTS showed USP6 gene rearrangement. RT-PCR was performed in those cases with detected USP6 gene rearrangement and sufficient tissue samples for RT-PCR. The MYH9-USP6 fusion gene was detected in 1 case (1/8) of the cellular FTSs, while no target fusion partner was detected in the classic FTS. Conclusions: FTS is a relatively rare benign fibroblastic or myofibroblastic tumor. Our study and recent literature find that some of the classic FTS also show USP6 gene rearrangements, suggesting that classical FTS and cellular FTS are likely to be at different stages of the same disease (spectrum). FISH for USP6 gene rearrangement may be used as an important auxiliary diagnostic tool in distinguishing FTS from other tumors.

Desmoid-type fibromatosis in splenic hilum with rupture of lienal artery aneurism in a 17-year-old male

Desmoid Fibromatosis (DF) is locally aggressive benign fibroblastic or myofibroblastic tumor with no metastatic potential, but has high recurrence rate. The symptoms vary according to tumor location, abdominal or extra-abdominal.

Clinicopathologic and genetic characterization of angiofibroma of soft tissue: a study of 12 cases including two cases with AHRR::NCOA3 gene fusion.

Angiofibroma of soft tissue (AFST) is a benign tumour characterised by prominent arborizing blood vessels throughout the lesion. Approximately two-thirds of AFST cases were reported to have AHRR::NCOA2 fusion, and only two cases have been reported to have other gene fusions: GTF2I::NCOA2 or GAB1::ABL1. Although AFST is included in fibroblastic and myofibroblastic tumours in the World Health Organization's 2020 classification, histiocytic markers, especially CD163, have been reported to be positive in almost all examined cases, and it still remains the possibility of a fibrohistiocytic nature of the tumour. Therefore, we aimed to clarify the genetic and pathological spectrum of AFST and identify whether histiocytic marker-positive cells were true neoplastic cells. We evaluated 12 AFST cases, which included 10 cases with AHRR::NCOA2 and two with AHRR::NCOA3 fusions. Pathologically, nuclear palisading, which has not been reported in AFST, was detected in two cases. Furthermore, one tumour resected by additional wide resection revealed severe infiltrative growth. Immunohistochemical analysis indicated varying levels of desmin-positive cells in nine cases, whereas CD163- and CD68-positive cells were diffusely distributed in all 12 cases. We also performed double immunofluorescence staining and immunofluorescence in situ hybridisation in four resected cases with >10% desmin-positive tumour cells. The results suggested that the CD163-positive cells differed from desmin-positive cells with AHRR::NCOA2 fusion in all four cases. Our findings suggested that AHRR::NCOA3 could be the second most frequent fusion gene, and histiocytic marker-positive cells are not genuine neoplastic cells in AFST.

Desmoid Fibromatosis With TP53 Mutation and Striking Nuclear Pleomorphism.

Desmoid fibromatosis is a myofibroblastic neoplasm of intermediate biologic potential, which has a strong predilection for local recurrence but does not metastasize. Arranged in long, sweeping fascicles with infiltrative borders, desmoid fibromatosis typically consists of uniform, bland myofibroblastic spindle cells that harbor mutation of CTNNB1 (or less often APC). In this report, we present a remarkable case of desmoid fibromatosis associated with striking nuclear pleomorphism. We hypothesize that this striking pleomorphism is due to a germline TP53 mutation, a finding first suspected due to strong and diffuse p53 staining by immunohistochemistry and subsequently confirmed by molecular testing. The combination of the pleomorphism and TP53 mutation in desmoid fibromatosis represents a novel finding unreported in the literature.

Desmoid Tumor of the Abdominal Wall: A Case Report

Desmoid tumors alternatively known as aggressive fibromatosis are benign myofibroblastic neoplasms originating from the muscle aponeurosis and classified as deep fibromatoses and these tumors are non-cancerous growth that occurs in the connective tissue. These tumors constitute 3% of all soft tissue tumors and 0.03% of all neoplasms and they occur usually between the age group of 20-40 years with a strong prevalence among women with fertile age group. In female patients presenting a tumor of the lower abdominal wall especially after cesarian section, an endometriotic tumor as well as an aggressive desmoid tumor should be considered. Symptoms in correlation with the monthly period can facilitate the presurgical differentiation between endometriosis and fibromatosis. Ultrasound reveals the typical location of both tumors and its remarkable sonographic appearance. In the clinical practice, the desmoid fibromatosis of the lower abdominal wall is a very rare disease. We present a case of a 19-year-old pregnant and discuss diagnostic and therapeutic options by literature review. With the knowledge of the prognosis of the desmoid fibromatosis and the respective treatment options including wait and see, complete surgical resection with macroscopically free margins and adjuvant approaches is essential to avoid further interventions and progression of the locally destructive tumor.
 EMCJ. July 2022; 7(2): 28-31

Clinico-histopathological evaluation of spindle cell soft tissue tumours

Introduction: Spindle cells are of mesenchymal origin and part of connective tissue. Soft tissues defined as non-epithelial, extra skeletal tissues of the body that may be voluntary muscles, fat and fibrous tissue and vessels. Soft tissue tumours are defined as mesenchymal proliferation which occur in the extraskeletal nonepithelial tissues of the body, excluding the viscera, coverings of brain and lymphoreticular system. Aims: The aims of the study is to classify according to WHO, evaluate the incidence rate and age, sex, site wise distribution and histopathological findings of the various types of spindle cell soft tissue tumours and comparing it with national and international study.Materials and Methods: The present study was done on surgical specimens received in Department of Pathology from August 2019 to August 2021. The Autolysed, poorly preserved specimens were excluded from the study. The specimens were fixed, grossly examined, representative tissue bits taken, processed in automated tissue processor for routine paraffin embedding, Tissue sectioning by microtomy and staining with the routine hematoxylin and eosin method done. Special stains were used if necessary. The microscopic examination was done and the results were analysed. Results: Out of 110 cases of spindle cell soft tissue tumors, most common tumors were Peripheral nerve sheath tumours (34.5%) followed by Fibroblastic and myofibroblastic tumours (22.7%). Most of the cases in present study occur between 21-30 years of age and more common in males. Higher rates of tumours located in head and neck region (36.4%). Conclusion: Spindle cell soft tissue tumours are classified according to morphological and histogenetic basis. Definite diagnosis especially for difficult cases should be made by performing immunohistochemistry and molecular biology. Present study was unique on the basis of that it includes spindle cell soft tissue tumours.

Study of Histomorphological Spectrum of Mesenchymal Tumors of GIT at Tertiary Care Centre

Introduction: Mesenchymal neoplasms of gastrointestinal tract are a group of rare tumors with overlapping histological features. There is significant morphologic overlap among diagnostic entities on the differential of mesenchymal lesions. So, use of a panel of immunohistochemical antibodies is necessary for accurate characterization of mesenchymal lesions of gastrointestinal system. Aim: The study was conducted in a tertiary care hospital in western India between January, 2019 to June 2020 to study the histomorphological spectrum and utility of IHC in the final diagnosis of mesenchymal tumor of GIT. Material & Methods: The cases were selected on the basis of inclusion & exclusion criteria defined and thereafter a panel of IHC antibodies was applied to diagnose mesenchymal tumors of gastrointestinal tract. Results: The study included 92 cases with a clinical and provisional morphologic diagnosis of mesenchymal tumors of GIT, mesentery and omentum. 25.00% cases of MT of GIT and were diagnosed on morphology alone. While, 75.00% required IHC for final diagnosis. Tumors with spindle cell morphology 61.95%, epithelioid cell morphology 5.80%, with mixed (spindle+epithelioid) cell morphology 10.14% and pleomorphic cell morphology 1.45%. Using” WHO 2013 of soft tissue tumors” MT of GIT were classified according to clinical behavior in to Benign tumors in 44.57% cases, lipoma being the commonest tumour diagnosed 34.15% cases. Intermediate tumors in 8.70% cases, all cases 100% being fibromatosis. Malignant tumors in 46.74% cases. Using “WHO 2019 of MT of Digestive System”, tumors were classified based on cell type. The commonest phenotype was “GIST” with 42.39% cases, followed by the second common phenotype “Adipose and Myofibroblastic tumor” with 33.69% cases, “Smooth and Skeletal Muscle tumors” with 9.78% cases. “Neural Tumors” with 7.63% cases, “Vascular and Perivascular” with 5.43% cases. Conclusion: GIST are the commonest MT of GIT. The availability of targeted chemotherapy warrants confirmation and ruling out GIST amongst all MT on priority basis. IHC panel should be applied in stepwise manner over “morphologically suspicious” cases Mesenchymal Tumors of GIT to diagnose and rule out GIST with first panel being CD117 and DOG1. These optimize the use of antibodies and make it cost effective. Keywords: Mesenchymal tumors, GIST, CD 117, DOG 1 antibody

Current management of benign retroperitoneal tumors

Benign retroperitoneal tumors (BRT) represent a rare group of heterogeneous diseases. The literature lacks high-quality evidence about the optimal management of BRT, and most of the information available takes the form of case reports or case series. The aim of this review is to provide an overview of current management strategies for adult patients with BRT.A literature search using PubMed indexed articles was conducted and BRT were classified into five different biological subgroups: 1) lipomatous tumors, 2) smooth muscle tumors, 3) peripheral nerve sheath tumors, 4) myofibroblastic tumors, and 5) others. Tumors that are primarily pelvic in origin were excluded.Despite the significant heterogeneity of the disease, several generic considerations have emerged and can be applied to the management of BRT. Specifically, the risk of misdiagnosing a BRT with another pathology such as retroperitoneal sarcoma is notable. When encountered, suspected BRT should therefore be referred to a specialized sarcoma center. Multidisciplinary tumor boards, present at these centers, have a pivotal role in managing BRT. The decision of whether to offer surgery, nonsurgical treatment or a “watch-and-wait” approach should be made after multidisciplinary discussion, depending on tumor histology. Moving forward, collaborative research efforts dedicated to BRT remain crucial in gathering evidence and knowledge to further optimize patient care.

INTRA-ABDOMINAL DESMOID TUMOUR- A RARE CASE REPORT WITH REVIEW OF LITERATURE.

Introduction: Desmoid tumours (DTs) are benign, slowly growing deep seated monoclonal myo-fibroblastic neoplasms. It arises from musculoaponeurotic stromal elements. The incidence in the general population is 2-4 cases per million people per year. DTs are typically sporadic; and can occur anywhere in the body. A 30 year male patient presented with a giant intraabdominal DT is discussed here with review of available literature. DTs areDiscussion: benign, deep-seated slowly growing monoclonal myo-fibroblastic neoplasms arise from musculoaponeurotic stromal elements. Diagnosis may be confirmed with biopsy and immunohistochemistry. Preoperative assessment with MRI, CT with angiogram are imperative for definitive surgical resection. There are roles of chemotherapy and radiation therapy in management of primary and recurrent lesions. The surgical resection remains the mainstay of its management. Conclusions: The management of DT is challenging. Surgical resection is the cornerstone of its management. Chemotherapy and radiation therapy in management of primary and recurrent lesions may be considered.

Mesenchymal Neoplasms of the Prostate and Seminal Vesicles: Spectrum of Disease with Radiologic-Pathologic Correlation.

There is a wide spectrum of benign and malignant mesenchymal neoplasms of the prostate, which account for less than 1% of all prostatic tumors. These include distinctive tumors that arise from the specialized prostatic stroma and site-agnostic neoplasms such as smooth muscle tumors, fibrous or myofibroblastic neoplasms, neurogenic tumors, vascular tumors, and a plethora of sarcomas. Select tumors show classic sites of origin within the prostate. While stromal tumors of uncertain malignant potential (STUMPs) commonly involve the peripheral zone at the prostate base, leiomyomas typically originate from the central prostate toward the apex. Some "prostatic" neoplasms such as gastrointestinal stromal tumors, solitary fibrous tumor (SFT), paragangliomas, and neurogenic tumors arise primarily from periprostatic soft tissues. Most mesenchymal tumors of the prostate and seminal vesicles manifest as large tumors that cause nonspecific symptoms; prostate-specific antigen level is not typically elevated. Diverse mesenchymal neoplasms demonstrate characteristic histopathologic and immunocytochemical features and variable cross-sectional imaging findings. While leiomyoma and SFT typically display low signal intensity on T2-weighted images, synovial sarcomas commonly show hemorrhage. Diagnosis is difficult because of the rarity and lack of awareness of the tumors and the significant overlap in histopathologic features. Select tumors show characteristic genetic abnormalities that allow the diagnosis to be established. For example, more than 90% of SFTs are characterized by a unique NAB2-STAT6 gene fusion, and more than 95% of synovial sarcomas are associated with a distinctive SYT-SSX chimeric transcript. Accurate diagnosis is imperative for optimal management owing to markedly different tumor biology as well as attendant therapeutic and prognostic implications. While STUMPs commonly recur, sarcomas typically charter an aggressive course with poor prognosis. Online supplemental material is available for this article. ©RSNA, 2022.

Pulmonary inflammatory myofibroblastic tumor in a breast cancer patient, a rare presentation

Inflammatory myofibroblastic tumor (IMT), a benign and rare neoplasm, of mesenchymal origin, pseudoarcomatous, is responsible for about 0.7% of all neoplastic presentations in the pulmonary region, being the most frequent cause of pulmonary nodules in pediatric patients, approximately 50% of the presentations. Thus, the present study aims to report a rare case of IMT in the lung site in a 31-year-old patient undergoing treatment for breast cancer, according to a literary review, relating the data according to the clinical presentation. Due to scarce documentation in the medical literature, no cases were found similar to the one described in relation to the reported oncological primary condition of the patient, making the present case a clinical challenge in modern medical practice.

The Role of Video-Assisted Thoracoscopic Surgery in Pediatric Oncology: Single-Center Experience and Review of the Literature.

Aim: Video-assisted thoracoscopic surgery (VATS) has been widely used in the last decades. Nevertheless, the pros and cons of thoracoscopy vs. open surgery in pediatric oncology are still under debate. In literature, VATS has been applied for both diagnostic and ablative surgery to treat neurogenic tumors, thymic neoplasms, lung tumors and metastases, germ cell tumors, lymphoproliferative diseases, and other rare tumors. Recent reviews described excellent outcomes in pediatric oncology as well as in the treatment of adult lung cancer, with a significantly higher rate of mortality and complication in thoracotomy compared to VATS. We reviewed our experience on thoracoscopy in pediatric malignancy and compared it to the literature.Materials and Methods: This was a retrospective cohort-study of pediatric oncological patients who underwent VATS at our institution from 2007 to 2020, and a review of the recent literature on the topic.Results: A total of 43 procedures were performed on 38 oncological patients (18 males, 20 females). Median age was years 7.72 (0.35–18.6). Diagnosis: 10 neurogenic tumors, nine hematological diseases, five metastases, four lypoblastomas, three thymic pathologies, three germ cell tumors, two pleuropneumoblastomas, two myofibroblastic tumors, one myoepithelial carcinoma, one liposarcoma, and three suspected oncological mass. In three cases, a 3D model was elaborated to better plan the surgical approach. Diagnostic biopsies were 22 (51.1%), and ablative surgeries, 21 (48.9%). One neurogenic tumor was resected with the Da Vinci Robot. Median operative time was 120 min (30–420). A drain was left in place in 20 (46.5%) for a median of 4 days. Median length of hospitalization was 5 days (1–18). One case (2.3%) was converted (intraoperative bleeding). There were three post-operative complications (7.0%): one pneumonia, one pleural effusion, and one diaphragmatic paralysis (need for plication). Results were compared to recent literature, and morbidity and conversion rate were comparable to reviewed publications.Conclusion: VATS represents a valuable tool for diagnostic and therapeutic procedures in pediatric oncology. Nonetheless, it is a challenging technique that should be performed by expert surgeons on oncological and mini-invasive surgery. Three-dimensional reconstruction can optimize the pre-operative planning and guarantee a safer and more targeted treatment. Finally, the advent of robotics-assisted surgery represents a new challenge that may further implement the advantages of VATS.

Fibroma of tendon sheath is defined by a USP6 gene fusion—morphologic and molecular reappraisal of the entity

Fibroma of tendon sheath (FTS) is an uncommon benign myofibroblastic neoplasm that arises in association with tenosynovial tissue. Fusions of the USP6 gene have been recently documented in a proportion of so-called “cellular FTS” but not in “classic FTS”. It remains unknown whether FTS can be defined by a USP6 fusion, regardless of cellularity, and what are USP6 fusion-negative “cellular FTS”. Furthermore, FTS with low cellularity seems to be frequently confused with desmoplastic fibroblastoma. We performed a comprehensive analysis, including targeted RNA sequencing, of 58 consecutive cases originally diagnosed as FTS (n = 49), desmoplastic fibroblastoma (n = 6), or nodular fasciitis (n = 3); the latter two at the predilection sites for FTS. After review of the original slides, 28 lesions were morphologically classified as FTS (13 “classic” and 15 “cellular”) and 23 as desmoplastic fibroblastoma. Among originally diagnosed FTS at the more cellular end of the spectrum, we identified seven lesions that shared many morphologic features of FTS but, in addition, showed several distinct morphologic features consistent with myofibroma, such as myoid appearance, branching thin-walled vessels, and perivascular growth. Targeted RNA sequencing showed a USP6 fusion in 17 of 18 analyzed FTS, regardless of cellularity, 0 of 5 desmoplastic fibroblastomas and 0 of 4 myofibromas. MYH9, COL1A1, and ASPN were identified as fusion partners in three cases each, and MIR22HG, CTNNB1, SPARC, CAP1, EMP1, LINC00152, NR1D1, and RAB1A in a single case each. FTS, regardless of cellularity, can be defined by a USP6 fusion with a variety of fusion partners. More cellular lesions exhibiting some morphologic features of FTS but lacking a USP6 fusion tend to be myofibromas.

Groin Pain - Weightlifter

HISTORY: A 25 y.o. male weightlifter presented for progressive R groin pain over the past 4 months. He describes gradual onset of intermittent sharp pain located over the anterior groin with radiation down the anterior thigh to the knee. Associated with numbness/tingling in the same distribution and swelling in the R groin. The pain and numbness recently began radiating to the R low back and waking him up at night. Symptoms are aggravated by prolonged standing, sitting, squatting and lifting. He denies focal weakness, change in bowel/bladder function, fevers, chills, night sweats or weight loss. PHYSICAL EXAMINATION: Gait: Normal. Inspection: Unremarkable. Palpation: TTP in the RLQ and groin with fullness. ROM: Full and symmetrical. Strength: Painful 5/5 hip flexion, abduction and adduction. Positive Thomas test. Negative femoral log roll, FADIR, FABER, Trendelenberg. Negative SLR. Neuro: Decreased sensation to light touch over anterior thigh. 2+ patellar and achilles DTR. Intact heel/toe walk. Vascular: DP pulses 2 + . DIFFERENTIAL DIAGNOSIS: 1. Lumbar radiculopathy 2. Meralgia paresthetica 3. Hip flexor/iliopsoas strain 4. Athletic pubalgia 5. Pelvic mass TEST AND RESULTS: XR: Unremarkable. US GROIN: Benign b/l lymphadenopathy w/o hernia or suspicious findings. MR L-SPINE: Unremarkable L-spine. Partially-imaged large R retroperitoneal lesion. CT ABD/PELVIS W CONTRAST: Heterogeneous mass arising from the R psoas muscle (8.5 x 6.4 x 7.5 cm) with calcifications at the inferior aspect. The mass displaces and compresses the R common iliac a/v and encases the R external iliac a/v. CT CHEST WO CONTRAST: No evidence of intrathoracic metastatic disease. FINAL WORKING DIAGNOSIS: Right retroperitoneal pelvic sarcoma with involvement of right external iliac artery and vein TREATMENT AND OUTCOMES: Core needle biopsy showed a low grade spindle cell myofibroblastic neoplasm. Given the lesion’s aggressive appearance, however, this likely represented a sampling of reactive tissue adjacent to an unsampled high grade sarcoma. He underwent radical resection of retroperitoneal pelvic mass with segmental resection and anastomosis of the R external iliac artery and vein, extensive ureterolysis of R ureter and neurolysis of R femoral and obturator nerve. Pathology results are pending and will guide further multimodality treatment.

Update of pediatric soft tissue tumors with review of conventional MRI appearance-part 2: vascular lesions, fibrohistiocytic tumors, muscle tumors, peripheral nerve sheath tumors, tumors of uncertain differentiation, and undifferentiated small round cell sarcomas.

There are numerous soft tissue tumors and tumor-like conditions in the pediatric population. Magnetic resonance imaging is the most useful modality for imaging these lesions. Although certain soft tissue lesions exhibit magnetic resonance features characteristic of a specific diagnosis, most lesions are indeterminate, and a biopsy is necessary for diagnosis. We provide a detailed update of soft tissue tumors and tumor-like conditions that occur in the pediatric population, emphasizing each lesion's conventional magnetic resonance imaging appearance, using the recently released 5th edition of the World Health Organization Classification of Soft Tissue and Bone Tumors as a guide. In part one of this review, pediatric tumor-like lesions, adipocytic tumors, fibroblastic and myofibroblastic tumors, and perivascular tumors are discussed. In part two, vascular lesions, fibrohistiocytic tumors, muscle tumors, peripheral nerve sheath tumors, tumors of uncertain differentiation, and undifferentiated small round cell sarcomas are reviewed. Per the convention of the WHO, these lesions involve the connective, subcutaneous, and other non-parenchymatous organ soft tissues, as well as the peripheral and autonomic nervous system.