Soft Tissue Tumors Research Articles

Percutaneous cryoablation in soft tissue tumor management: an educational review

Abstract Background Percutaneous cryoablation (PCA), having shown effectiveness in treating liver, lung, prostate, breast, and kidney tumors, is now gaining attention for the treatment of soft tissue tumors. PCA functions by freezing tissue, which induces ice crystal formation and cell death without damaging collagen structures. Technical considerations include the selection and handling of cryoprobes and cryogenic agents, procedural duration, and choice of image guidance for precision. This review aims to synthesize the mechanisms, applications, and technical aspects of PCA in the treatment of soft tissue tumors. Methods Adhering to PRISMA 2020 guidelines, a review was conducted of studies published prior to March 2024 that investigated PCA of soft tissue tumors. The review focused on technical and procedural aspects of cryoablation, cryobiological principles, cellular and tissue responses to extreme cold, intra- and post-procedure physiological mechanisms during and post-procedure, and main clinical applications. Results PCA is efficient in treating soft tissue tumors, including desmoid tumors, vascular malformations, and abdominal wall endometriosis. Several cryobiological mechanisms are involved, notably ice crystal formation, cellular dehydration, osmotic effects, and the inflammatory response, all of which contribute to its efficacy. Key technical aspects include the choice of cryoprobes, cryogenic agents (argon gas or liquid nitrogen), and the duration and control of freezing/thawing cycles. PCA also frequently outperformed traditional treatments like surgery and radiotherapy in terms of pain reduction, tumor size reduction, and patient outcomes. Moreover, its nerve sideration properties make it effective under local anesthesia. Conclusion Demonstrating substantial pain reduction, tumor size decrease, and high technical success rates, PCA offers a promising and minimally invasive alternative for soft tissue tumor treatment. Critical relevance statement Percutaneous cryoablation provides a minimally invasive, precise alternative for soft tissue tumor management, advancing clinical radiology by offering effective treatment with reduced patient risk and enhanced outcomes through image-guided procedures. Key Points Percutaneous cryoablation (PCA) offers a promising, minimally invasive alternative for managing soft tissue tumors. PCA employs image-guided techniques to accurately target and treat tumors, ensuring high precision and control. PCA preserves structures like collagen, reduces pain, decreases tumor size, and generally enhances patient outcomes. Graphical Abstract

Abstract C050: Leveraging ECM deposition by CAF-like Ewing sarcoma tumor cells to target micrometastases with matrix-binding VHHs

Abstract Ewing sarcoma (EwS) is an aggressive bone and soft tissue tumor and EwS patients often succumb to their disease years after initial treatment due to relapses at metastatic sites. Novel therapeutic strategies are needed that can successfully eliminate microscopic residual disease foci that persist at the end of primary therapy. Extracellular matrix (ECM) proteins in the tumor microenvironment (TME) provide critical pro-survival and pro-invasion signals to tumor cells. Our published and unpublished data show that the glycoprotein tenascin-C (TNC) is enriched in EwS metastases and that TNC and other pro-tumorigenic ECM proteins are deposited by subpopulations of CAF-like tumor cells that are activated in response to tumor and TME-derived TGF-beta ligands. TNC is abundantly produced by multiple human tumors of epithelial and non-epithelial lineage but is otherwise rarely expressed outside of development and wound healing. Importantly, TNC is specifically enriched in metastatic lesions where it has been implicated as a mediator of metastatic competence and treatment resistance. In the current work we have tested whether the TNC-rich TME of disseminated EwS tumor foci could be leveraged to direct therapies to sites of residual micrometastatic disease. To achieve this, we generated monovalent and bivalent anti-human TNC VHHs (hTNC-VHH) using a mammalian expression platform. Camelid-derived hTNC-VHH sequences were sourced from published literature. VHHs are single domain heavy chain only antibody fragments with higher stability and tissue penetration than conventional monoclonal antibodies. Using EwS tumor spheroids in collagen-rich 3D culture, hTNC-VHH penetrated dense ECM matrices and bound through multiple cell layers in under 10 minutes. hTNC-VHH accumulated in TNC-positive but not TNC-knockout EwS spheroids and were retained beyond 96 hours. To assess their potential to drive protein and immune therapies to TNC-rich TMEs, we fused hTNC-VHH to immune modulating CD3- and CD28-activating VHHs. These hTNC-VHH-CD3/CD28-conjugates promoted immune cell activation and tumor cell death in PBMC-tumor co-culture assays as determined by CD25 flow cytometry and fluorescence microscopy, respectively. To assess in vivo localization, fluorescently-tagged hTNC-VHH were intravenously injected into mice that had been xenografted with EwS cells. Tissue microscopy confirmed selective binding of hTNC-VHH to small lung and liver EwS micrometastases in less than 4 hours. VHHs were not retained in non-tumor bearing organs including the brain and heart or in tumor-free lung and liver regions. Experiments are ongoing to assess anti-tumor efficacy and pharmacodynamics of hTNC-VHH conjugates in EwS xenografts. Together these findings suggest that the ECM-remodeling properties of CAF-like EwS cells can be exploited to recruit novel ECM-targeting protein therapeutics to micrometastases. If successful, this innovative approach could eradicate microscopic residual disease and prevent metastatic EwS recurrence. Citation Format: Emma D. Wrenn, Jason P. Price, Raymond O. Ruff, Nicolas M. Garcia, James M. Olson, Elizabeth R. Lawlor. Leveraging ECM deposition by CAF-like Ewing sarcoma tumor cells to target micrometastases with matrix-binding VHHs [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C050.

Abstract C008: New insights from a novel mouse model of synovial sarcoma

Abstract Mouse models are the basis of preclinical and translational research in solid tumors. Multiple methods exist to induce tumor formation in mice, including genetically engineered mouse models, chemotoxic agents, injection of tumor cells, and xenograft approaches. Synovial sarcoma, a rare highly malignant soft-tissue tumor, poses a serious threat to patients due to its aggressive nature and associated high rates of mortality and morbidity. This disease's underlying cause and development remain poorly comprehended, and existing treatment approaches have yielded unsatisfactory outcomes. In the last two decades, numerous effective animal models of soft tissue sarcoma (STS) have been created, primarily utilizing genetically engineered mice and zebrafish, however long latency of tumor development for several months in these models creates a barrier for practical in-vivo experiments for drug testing or manipulating the cellular composition of the tumor microenvironment. In studying cancer immunotherapy, it is important to consider aspects of antitumor immune responses and to produce a model that mimics the complexity of the immune system We have generated a new mouse model of synovial sarcoma of exceptionally fast tumor development. Intramuscular delivery of Cre recombinase protein in mice which drives conditional knockdown in PTEN, stabilization of β-catenin, and formation of fusion oncogenes of SS18-SSX2 was sufficient to initiate high-grade synovial sarcomas with myofibroblastic differentiation in 3 weeks. As immunotherapy is increasingly applied to sarcomas, our mouse model will serve as a great tool for preclinical data. Flow cytometry-based analysis of peripheral blood shows significant changes in immune cell populations as early as five days after Tat-Cre injection and continues throughout the development of synovial sarcoma. These results suggest a significant systemic phenotypic alteration of circulating immune cells, which may impact other major organs in this genetic mouse model of synovial sarcoma. Single- cell RNA sequencing of the CD45+ leukocytes in the tumor microenvironment reveals subsets that may promote tumor progression. Our work promises to significantly enhance our understanding of the pathogenesis of this disease and establish a reliable preclinical platform for devising and assessing therapeutic interventions. Citation Format: Hesham Mohei, Donn Van Deren, Irene S. Molina, Malay Haldar. New insights from a novel mouse model of synovial sarcoma [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C008.

An Observational Study on The Role of Magnetic Resonance Imaging in The Evaluation of Soft Tissue Tumors with Histopathological Correlation at Tertiary Care Centre

Background: The primary aim of this study is to evaluate the role of magnetic resonance imaging (MRI) in the assessment of soft tissue tumors with histopathological correlation at a tertiary care center. Methods: An observational study was conducted on 75 patients (n = 75) in the Department of Radiodiagnosis over 18 months. The targeted population comprised patients who presented to the Radiodiagnosis Department for radiological imaging of soft tissue tumors. Results: Out of 75 cases, 20% were found to have benign tumors, while 80% were found to have malignant tumors. The most frequent benign tumor was fibromatosis, with n = 10 cases (13.33%), and the most common malignant tumor was synovial sarcoma, with n = 14 cases (18.66%). The benign age group ranged from 11 to 20 years. T2-weighted heterogeneous hyperintensity was noted more frequently in malignant lesions, demonstrating a high positive predictive value; that is, 83% of malignant tumors exhibited changes on diffusion-weighted imaging/ apparent diffusion co efficient (DWI/ADC). Low-grade malignant lesions showed no restrictions. Most benign lesions displayed restrictions, with a high positive predictive value of 98.14%, specificity of 93.33%, and sensitivity of 88.33%. Conclusions: Soft tissue tumors can be detected and locally staged using MRI; thus, this technique has proven its value. Intralesional hemorrhage and calcification are two parameters that have been shown to have no substantial association with cancer. Due to its high sensitivity, MRI is a viable option for evaluating soft tissue tumors.

Angiofibrolipoma in the Head and Neck Region: A Case Report and Literature Review.

Angiofibrolipomas are rare, benign soft tissue tumors composed of mature fat cells, blood vessels, and fibrous connective tissue. Typically occurring in subcutaneous locations, this case report presents a unique instance of an angiofibrolipoma arising in the pharynx. According to our review of the literature, it is the second reported case in the pharynx and the sixth in the head and neck region. A 58-year-old woman presented with a 1 year history of globus sensation and an incidentally-discovered extra-oral polyp. Endoscopic examination revealed the polyp originating from the upper esophagus and extending into the pharynx. Magnetic resonance imaging confirmed the nature and extent of the lesion. The polyp was successfully removed via endoscopic resection, and histopathological analysis confirmed the diagnosis of angiofibrolipoma. This case highlights the rarity of pharyngeal angiofibrolipomas and underscores the importance of endoscopic evaluation for patients presenting with ambiguous pharyngeal symptoms. While surgical resection is generally recommended for such tumors, endoscopic removal can be a safe and effective option for smaller pedunculated lesions.

Clinico-dermoscopic and Histopathological Evaluation of Benign Skin, Soft Tissue and Appendageal Tumours of Skin: A Cross-sectional Study from a Tertiary Care Hospital

Abstract Background: Benign skin, soft tissue and appendageal tumours of skin are one of the most frequently encountered skin disorders. An organised systematic approach along with dermoscopic and histopathological examination can aid in the diagnosis of these diverse disorders. Objective: To evaluate clinico-dermoscopic and histopathological findings of benign skin, soft tissue and appendageal tumours of skin in patients attending a tertiary care hospital. Methods: Cross-sectional hospital-based study where patients of all age groups irrespective of gender suspected of having benign skin, soft tissue and appendageal tumours were enrolled. Clinical, dermoscopic and histopathological findings were recorded and the agreements between them were evaluated using the Cohenʼs Kappa coefficient. Results: The study included a total of 415 patients with a mean age of 37.9 ± 15.59 years and a male to female ratio of 1:1.3. The mean duration of the disease was 4.3 ± 2.14 years. Soft tissue tumours were the commonest (60%), followed by benign skin tumours (24.3%) and benign appendageal tumours (17.1%). A good agreement between dermoscopic and clinical diagnosis was found (Cohenʼs Kappa = 0.879) and between dermoscopic and histopathological diagnosis was also found (Cohenʼs Kappa = 0.789). Conclusion: This study infers that benign tumours of the skin include a heterogeneous group of skin disorders affecting a heterogeneous population. Dermoscopy improved the diagnostic accuracy of this large group of skin disorders and reduced the number of unnecessary excisions; however, histopathology remains the benchmark diagnostic tool to differentiate these tumours from other benign tumours and their malignant counterparts.

Deciphering the enigma of glomus tumors: A case series

Glomus tumors are rare contributing to less than two percent of all soft tissue tumors. Given the rarity of this tumor, there is a possibility of low suspicion and a missed clinical diagnosis. This case series suggests diagnostic and morphological clues for early diagnosis of this tumor.This retrospective study includes nine interesting cases of glomus tumors from January 2015 to January 2024. Data was tabulated and analysed by descriptive statistics using Microsoft Excel 2016. In this series the glomus tumors showed a mean age of (37.67± 17.5 years). Male to female ratio was 1.25:1. Most common sites were digital parts of extremities (5/9, 55.56%). Four of these digital locations were subungual (4/5, 80%). The left side (5/9, 55.56%) was the most common laterality. Duration of symptoms till diagnosis was established showed a median of three months [range was one month to nine years]. All nine cases presented with pain. The mean size of glomus lesions was 2.1±1.5 cm). Multiplicity was observed in (2/9, 22.22%) cases. Eight cases were benign (8/9, 88.89%) while one was malignant (1/9, 11.11%). Two out of these eight benign cases were glomangiomatosis. Excision biopsy was the surgical procedure performed in all of our benign cases while the malignant case was treated with amputation of the finger.Diagnosis of glomus tumors requires a high index of clinical suspicion, especially in extra-digital locations. Awareness is essential for early diagnosis and treatment of this lesion, as it is an extremely painful condition and pain is out of proportion to the size of the lesion. Magnetic Resonance Imaging (MRI) is the first investigation of choice for imaging. An early biopsy can confirm the diagnosis of a glomus tumor in time. Complete surgical excision is curative with a low risk of recurrence.

Cognitive Bias: Chromoblastomycosis misdiagnosed as a giant cell tumor of soft tissue in a kidney transplant recipient.

Cognitive Bias: Chromoblastomycosis misdiagnosed as a giant cell tumor of soft tissue in a kidney transplant recipient.

Prospective Screening of Cancer Syndromes in Patients with Mesenchymal Tumors

Background: The etiology of most mesenchymal tumors is unknown, and knowledge about syndromes with an increased risk of tumors in bone or soft tissue is sparse. Methods: We present a prospective germline analysis of 312 patients with tumors suspected of being sarcomas at a tertiary sarcoma center. Germline and tumor whole genome sequencing, tumor transcriptome, and methylome analyses were performed. Results: Germline pathogenic or likely pathogenic variants associated with an increased risk of tumors were detected in 24 patients (8%), of which 11 (4%) harbored a detectable second hit in the tumor. Second hits were confirmed in genes with (NF1, RB1, TP53, EXT2, and SDHC) and without (ATM, CDC73, MLH1, MSH6, POLG, and KCNQ1) known association with mesenchymal tumor predisposition. Sarcomas from two Lynch syndrome patients showed mismatch repair deficiency, predicting a treatment response to immune checkpoint inhibitors (Level 1 biomarker according to the FDA (Federal Drug Administration) and ESMO (European Society for Medical Oncology)). None of the three CHEK2 carriers had a second hit in the tumor, suggesting a weak link to sarcoma. Conclusions: We conclude that second-hit analyses can be used in standard of care to identify syndrome-related tumors. This approach can help distinguish true manifestations of tumor syndromes from unrelated germline findings and enhance the understanding of germline predisposition in soft tissue tumors. Prospective screening using germline whole genome sequencing should be considered when comprehensive somatic sequencing is introduced into clinical practice.

Endometriosis of a postoperative scar

One of the long-term complications of abdominal surgery is endometriosis of the postoperative scar (EPS). The frequency of this condition is 0.03–1.08%. Mechanical implantation of endometrium during primary surgery plays a leading role in the pathogenesis of EPS. Together with clinical manifestations, ultrasound and magnetic resonance imaging are important diagnostic tools for this postoperative complication. Differential diagnosis requires excluding suture granulomas, hematomas, fibroids, hernias, lipomas, seromas, abscesses, and other malignant and benign soft tissue tumors in the area of the scar. This article describes a case of EPS in two women who had undergone cesarean section. Adequate removal of endometrial infiltrates, followed by abdominoplasty, allowed them to avoid recurrence and achieve optimal cosmetic results. Currently, in order to prevent the occurrence of EPS after surgical delivery, it is recommended to change gloves after removing the afterbirth and before restoring the integrity of the anterior abdominal wall, as well as limiting the edges of the wound to the abdominal cavity.

Benign bone and soft tissue tumors of the foot.

Tumors of the foot are a heterogeneous group of neoplasms that either affect soft tissues or bone, with a predominance being benign. Mistakes in the diagnosis of neoplastic conditions are common. A correct diagnostic approach supported by radiological and histological examination is mandatory. In this review, we highlight current standards in diagnosis, clinicopathological presentation, and imaging features.

A Rare Case of Pancreatic Metastasis of Synovial Sarcoma

Synovial sarcoma is a rare mesenchymal tumor of soft tissue and has high metastatic potential. The most common sites of metastases are the lungs, lymph nodes and bones. The pancreatic location of a synovial sarcoma is very rare. Histological and immunohistochemical examinations are essential to confirm the diagnosis. We report the case of a 57-year-old patient treated for (SS) of pulmonary localization 2 years ago and who currently presents with pancreatic localization.

Consensus recommendations for an integrated diagnostic approach to peripheral nerve sheath tumors arising in the setting of Neurofibromatosis type 1 (NF1).

Consensus recommendation published in 2017 histologically defining atypical neurofibromatous neoplasm of uncertain biologic potential (ANNUBP) and malignant peripheral nerve sheath tumor (MPNST) were codified in the 2021 WHO Classification of Tumors of the Central Nervous System and the 2022 WHO Classification of Tumors of Soft Tissue and Bone. However, given the shift in diagnostic pathology toward the use of integrated histopathologic and genomic approaches, the incorporation of additional molecular strata in the classification of Neurofibromatosis Type 1 (NF1)-associated peripheral nerve sheath tumors should be formalized to aid in accurate diagnosis and early identification of malignant transformation to enable appropriate intervention for affected patients. To this end, we assembled a multi-institutional expert pathology working group as part of a "Symposium on Atypical Neurofibroma: State of the Science". Herein, we provide a suggested framework for adequate interventional radiology and surgical sampling, and recommend molecular profiling for clinically or radiologically worrisome non-cutaneous lesions in patients with NF1 to identify diagnostically-relevant molecular features, including CDKN2A/B inactivation for ANNUBP, as well as SUZ12, EED, or TP53 inactivating mutations, or significant aneuploidy for MPNST. We also propose renaming "low-grade MPNST" to "ANNUBP with increased proliferation" to avoid the use of the "malignant" term in this group of tumors with persistent unknown biologic potential. This refined integrated diagnostic approach for NF1-associated peripheral nerve sheath tumors should continue to evolve in concert with our understanding of these neoplasms.

SATB2 is an Emergent Biomarker of Anaplastic Thyroid Carcinoma: A Series with Comprehensive Biomarker and Molecular Studies.

Anaplastic thyroid carcinoma (ATC) is a rare and aggressive thyroid malignancy typically comprised of undifferentiated tumor cells with various histologic morphologies, which makes the diagnosis challenging. These tumors commonly show loss of thyroglobulin and TTF1 with preservation of cytokeratin (67%) and Paired Box Gene 8 (PAX8) (55%) expression. Identification of a sensitive immunohistochemical stain to aid in the diagnosis of ATC would be beneficial. Immunohistochemistry (IHC) against special AT-rich sequence-binding protein 2 (SATB2) protein is a sensitive and specific marker expressed in colorectal adenocarcinoma and bone or soft tissue tumors with osteoblastic differentiation. However, SATB2 is also expressed in other sarcomatous/undifferentiated neoplasms lacking osteoblastic differentiation. Using quantitative reverse transcription PCR (RT-qPCR) we showed that there is variable expression of SATB2 mRNA expression in ATCs. To evaluate the role of SATB2 protein expression in ATC, we performed PAX8, SATB2, pancytokeratin (AE1/AE3 & CAM5.2), claudin-4 and TTF1 immunostaining on 23 cases. ATCs showed retained expression of PAX8 in 65% (15/23); SATB2 was detected in 74% (17/23); pancytokeratin was expressed in 65% (15/23); claudin-4 was expressed in 35% (8/23) and TTF1 showed expression in 13% (3/23) of cases. Furthermore, 83% (5/6) of ATCs which lacked SATB2 expression, retained PAX8 expression, while 88% (7/8) of the tumors without PAX8 expression were positive for SATB2. Differentiated follicular cell-derived thyroid cancers (n = 30), differentiated high grade thyroid carcinoma (n = 3), and poorly differentiated thyroid carcinoma (n = 8) were negative for SATB2 immunoreactivity. Next-generation selected cases detected the commonly identified oncogenic variants including those in BRAF, RAS, TP53, and TERT promoter. Overall, we hereby demonstrate that SATB2 IHC may be used to support the diagnosis of ATC.

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.

Intracranial pleomorphic liposarcoma misclassified as a pleomorphic xanthoastrocytoma by a DNA methylation classifier: illustrative case.

Recently, it has been shown that DNA methylation arrays and German Cancer Research Center (Deutsches Krebsforschungszentrum) methylation classifiers are useful aids in brain tumor diagnosis for cases in which histopathological diagnosis is difficult. However, not enough is known about diagnostic aids for intracranial liposarcoma (LPS). An 18-year-old woman with a history of natural killer/T-cell lymphoma, which had been treated with a bone marrow transplant and total body irradiation at age 11 years, presented with diplopia. Magnetic resonance imaging revealed a brain tumor in the posterior left temporal lobe, which was removed by craniotomy. The tumor was initially diagnosed as pleomorphic xanthoastrocytoma through histopathological and DNA methylation examination. She also had a soft tissue tumor in her left thigh, which was removed. It contained spindle cells with oval nuclei and highly pleomorphic cells and was diagnosed as radiation-induced LPS. Histopathological re-examination of the brain tumor led to a final diagnosis of pleomorphic LPS. In this report, the authors describe the case of a patient with an intracranial pleomorphic LPS that was initially classified as a pleomorphic xanthoastrocytoma by a DNA methylation classifier. Although DNA methylation classifiers are useful as diagnostic aids in cases in which definitive pathology is difficult to determine, there is a risk of misdiagnosis in some types of tumors. https://thejns.org/doi/10.3171/CASE24465.

Desmoplastic Fibroblastoma (Collagenous Fibroma) of the Knee: A Case Report and Literature Review.

Desmoplastic fibroblastoma, also known as collagenous fibroma, is a rare benign mesenchymal neoplasm that primarily arises in the subcutaneous tissue of upper extremities and limb girdles. The knee is an uncommon location for desmoplastic fibroblastoma. Recent studies have demonstrated the presence of immunoreactivity for FOS like 1 (FOSL1) and rearrangements of FOSL1. A 70-year-old woman presented with a 1-year history of a palpable mass in the medial aspect of the right knee. Physical examination revealed a 4-cm, elastic hard, mobile, nontender mass. Magnetic resonance imaging (MRI) showed a well-defined mass with prominent low signal intensity on all pulse sequences. Contrast-enhanced MRI demonstrated mild internal enhancement with rim enhancement. After an open biopsy, the lesion was successfully treated by complete excision. Histologically, the tumor was composed of bland spindle or stellate-shaped cells embedded in an abundant collagenous stroma. Immunohistochemically, the tumor cells showed diffuse nuclear positivity for FOSL1. These findings were consistent with a diagnosis of desmoplastic fibroblastoma. The patient was asymptomatic and there was no evidence of local recurrence eight months after surgery. Desmoplastic fibroblastoma is a distinctive benign soft-tissue tumor with FOSL1 immunoreactivity and should be clearly distinguished from more biologically aggressive mesenchymal neoplasms.

Positron emission tomography-magnetic resonance imaging applications in pediatric musculoskeletal tumors.

The hybrid imaging positron emission tomography/magnetic resonance (PET/MR) is an important tool in the management of pediatric oncology patients, particularly in malignant musculoskeletal pathologies, because it combines the functional and metabolic information of tumor provided by PET with the high soft-tissue contrast and the functional information offered by magnetic resonance imaging (MRI). We performed an observational retrospective study that included pediatric patients diagnosed with primary bone or soft-tissue sarcomas in the Pediatric Hematology and Oncology Unit at the HM Montepríncipe University Hospital, Boadilla del Monte, Madrid (Spain) who underwent whole-body 18F-fluorodeoxyglucose (18F-FDG) PET/MRI as a staging study and for follow-up evaluation for treatment response from September 2017 to January 2023. This study explores the protocols, the practical application of the PET/MRI technique and our clinical experience at our center in the diagnosis and follow-up of primary bone tumors and soft-tissue sarcomas in children. Seventy-one 18F-PET/MR studies were performed on 39 patients. Most of them (55%) were initial extension studies and (45%) were follow-up studies. Most of the patients studied were male (74.4%) with a median age of 15 years. Of the 39 cases, 51% were primary bone tumors while 18% were Langerhans cell histiocytosis and 21% soft tissue tumors. Of the 71 studies, five showed metastases at the initial diagnosis, three presented lymph node involvement, one with local infiltration, and one with pulmonary metastasis. PET/MR has represented a significant advancement in the evaluation of pediatric malignant neoplasms, with specific applications in musculoskeletal tumors showing clear benefits over PET/CT. The primary advantage is the reduction in ionizing radiation doses and the assessment of soft tissues, making it an excellent option for malignant musculoskeletal pathologies in pediatric patients who often require long-term follow-up. It is particularly useful for early tumor detection and functional therapy monitoring in oncology. The development of new protocols is making studies increasingly faster and better tolerated, even without the need for anesthesia. PET/MRI has shown to increase diagnostic accuracy in primary bone and soft tissue tumors, as it allows for the comprehensive evaluation of their morpho-metabolic characteristics, locoregional, and distant involvement in a single study. It is also useful in surgical planning and post-treatment follow-up.

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.

The Diagnostic And Prognostic Role Of Immunohistochemistry In Head & Neck Tumours Along With Radiological & Histopathological Study

Background: Head & neck tumors are defined as benign, premalignant & malignant tumors above the clavicles, except the tumors of brain, spinal cord and esophagus. This includes tumors of paranasal sinus, nasal cavity, salivary glands, thyroid and upper aerodigestive tract, lymph nodes of neck, skin & its appendages, soft tissue tumors, midline carcinomas & metastatic tumors. Ultrasonography, computed tomography, magnetic resonance imaging were the modalities for initial evaluation. Histopathology was the GOLD standard for diagnosis followed by IHC for confirmation because correct diagnosis & cancer subtyping of the neoplasia is essential for successful therapy and prognosis. Materials & Methods: Study was conducted for 2 years with 100 specimens of head & neck tumors. Thorough Radiological investigation was done followed by Histopathological examination including biopsy & whole resected specimens. IHC markers appropriate to the histopathological diagnosis was done. Results: Among 100 patients of head & neck tumors, most belonged to 5th decade with male: female ratio of 2.3:1. Squamous cell carcinoma (66%) followed by Lymphoma(11%), tumors of salivary glands(8%), metastatic lymphadenopathy(7%) were the lesions present. SCC was most common carcinoma in oral cavity, larynx, nasopharynx and ear with positive p63 marker. 1 case of Basal cell carcinoma with positive BerEP4 & in NHL, salivary gland tumors & Metastatic lymphadenopathy panel of IHC were included for confirmation. Conclusion: Immunohistochemistry has a diagnostic & prognostic role in Head & Neck tumors along with Radiological & histopathological examination.