The 2020 WHO Classification of Tumors of Soft Tissue: Selected Changes and New Entities

Solitary Fibrous Tumor of the Adrenal Gland

OBJECTIVES

Solitary fibrous tumor (SFT) is a mesenchymal neoplasm that can arise at various anatomic locations. It is characterized by inv12(q13q13)-derived NAB2::STAT6 fusion, resulting in the nuclear expression of STAT6. Primary SFT of the adrenal gland is rare. We launched a multi-institutional collaboration to comprehend the overarching demographics, clinical and follow-up, macroscopic, microscopic, IHC, and FISH features of 9 patients with SFT of the adrenal gland.

METHODS

We added a series of 9 patients to the collection of adrenal SFTs where the clinicopathologic parameters, including clinical presentation, imaging, histopathology, IHC, molecular profiles, and management and follow-up data, were analyzed comprehensively. A modified 4-variable risk stratification model, including age, tumor size, and necrosis, was applied.

RESULTS

Our series consisted of 6 male and 3 female patients, ranging in age from 19 to 64 years (mean, 49.3 years). Abdominal pain (4) and fever with abdominal pain (1) were the presenting symptoms in 5 patients. In the remaining 4 patients, the tumors were detected by abdominal imaging for hypertension and diabetes. The size of the tumor ranged from 2 cm to 10.5 cm in maximum dimension. All tumors exhibited the morphology of a spindle cell SFT with a patternless architecture; 3 had a focal storiform arrangement. STAT6 positivity was observed in all tumors, and 7 were positive for CD34. Surgical resection was the primary modality of treatment. No adjuvant therapy was administered. Follow-up ranging from 7 months to 23 months was available for 7 patients. All were alive without disease recurrence or metastasis. Risk stratification placed 8 (88.9%) patients into a low-risk category and 1 into an intermediate-risk category.

CONCLUSIONS

This series is the largest of adrenal SFTs to date. These tumors of the adrenal gland are predominantly spindle cell neoplasms with indolent behavior, with a wide age distribution and a slight male preponderance. Combining our cohort with the previously published cases, the majority of tumors fall into the low-risk category for the propensity to develop metastases. Owing to the rarity and age distribution associated with these tumors, the differential diagnosis is wide and requires a systematic approach for ruling out key differential diagnoses aided by STAT6 IHC.

Treatment, pathological characteristics, and prognosis of pulmonary inflammatory myofibroblastic tumor–a retrospective study of 8 cases

Objective

Inflammatory myofibroblastic tumor (IMT) is a rare disease. We reviewed data from eight patients diagnosed with pulmonary IMT (PIMT) at our hospital with the aim of summarizing and analyzing the characteristics of PIMT to improve our understanding of the disease.

Methods

From January 2012 to December 2019, eight patients underwent surgical intervention for PIMT at The First Affiliated Hospital of Bengbu Medical College. Resected tumors were subjected to pathological and immunohistochemical analyses. The follow-up duration for all patients ranged from 2 years and 3 months to 9 years and 9 months (median: 6 years and 9 months).

Results

The male:female ratio was 5:3, and the mean age was 48.50 years (21–74 years). Two patients (25%) with lung disease discovered via chest computed tomography during physical examinations had not experienced any symptoms. Six patients (75%) presented at the hospital because of cough, expectoration, blood in sputum, and chest tightness. Lesions from all eight patients were surgically removed, and PIMT was confirmed based on pathological examinations and immunohistochemical results. No patient received additional treatment after discharge. All cases have been followed up to the time of writing, without any tumor recurrence or distant metastasis.

Conclusion

The age of onset of PIMT is usually over 40 years, and its clinical symptoms are easily confused with those of lung cancer. PIMT can only be diagnosed by histopathology and immunohistochemistry. Complete surgical resection is the preferred treatment, as patients undergoing surgery require no additional treatment, such as chemotherapy, and the survival rate is good.

Resection of retroperitoneal tumors with inferior vena cava involvement without caval reconstruction

BACKGROUND AND OBJECTIVES

Retroperitoneal tumors with involvement of the inferior vena cava (IVC) often require resection of the IVC to achieve complete tumor removal. This study evaluates the safety and efficacy of IVC ligation without caval reconstruction.

METHODS

A retrospective chart review of patients who underwent IVC ligation (IVC-Ligation) and IVC resection with reconstruction (IVC-Reconstruction) at our institution between May 2004 and April 2021 was performed. Outcomes from the two surgical techniques were compared via univariate analysis using the Kruskal-Wallis test for continuous variables and Fisher's exact test for categorical variables.

RESULTS

Forty-nine IVC-Ligation and six IVC-Reconstruction surgeries were identified. There were no differences in baseline demographics, tumor characteristics, complication rates, postoperative morbidity, or overall 5-year survival between groups. IVC-Reconstruction patients were more likely to require intensive care unit admission (83% vs. 33%; p = 0.0257) and the IVC-Ligation cohort had a tendency to present with nondebilitating postoperative lymphedema (35% vs. 0%; p = 0.1615), which resolved for most patients.

CONCLUSIONS

IVC-Ligation is a viable surgical option for select patients presenting with retroperitoneal tumors with IVC involvement and provides acceptable short- and medium-term outcomes.

SMARCB1-Deficient Cancers: Novel Molecular Insights and Therapeutic Vulnerabilities

SMARCB1 is a critical component of the BAF complex that is responsible for global chromatin remodeling. Loss of SMARCB1 has been implicated in the initiation of cancers such as malignant rhabdoid tumor (MRT), atypical teratoid rhabdoid tumor (ATRT), and, more recently, renal medullary carcinoma (RMC). These SMARCB1-deficient tumors have remarkably stable genomes, offering unique insights into the epigenetic mechanisms in cancer biology. Given the lack of druggable targets and the high mortality associated with SMARCB1-deficient tumors, a significant research effort has been directed toward understanding the mechanisms of tumor transformation and proliferation. Accumulating evidence suggests that tumorigenicity arises from aberrant enhancer and promoter regulation followed by dysfunctional transcriptional control. In this review, we outline key mechanisms by which loss of SMARCB1 may lead to tumor formation and cover how these mechanisms have been used for the design of targeted therapy.

Mass Spectrometry Imaging Spatial Tissue Analysis toward Personalized Medicine

Novel profiling methodologies are redefining the diagnostic capabilities and therapeutic approaches towards more precise and personalized healthcare. Complementary information can be obtained from different omic approaches in combination with the traditional macro- and microscopic analysis of the tissue, providing a more complete assessment of the disease. Mass spectrometry imaging, as a tissue typing approach, provides information on the molecular level directly measured from the tissue. Lipids, metabolites, glycans, and proteins can be used for better understanding imbalances in the DNA to RNA to protein translation, which leads to aberrant cellular behavior. Several studies have explored the capabilities of this technology to be applied to tumor subtyping, patient prognosis, and tissue profiling for intraoperative tissue evaluation. In the future, intercenter studies may provide the needed confirmation on the reproducibility, robustness, and applicability of the developed classification models for tissue characterization to assist in disease management.

Giant renal schwannoma with obvious hemorrhage and cystic degeneration: a case report and literature review

BACKGROUND

Renal schwannomas are very rare and are usually benign. Its clinical symptoms and imaging features are nonspecific, and the diagnosis is usually confirmed by pathology after surgical resection.

CASE PRESENTATION

A 46-year-old Chinese female was admitted to the hospital with right flank pain that had persisted for the six months prior to admission. This pain had worsened for 10 days before admission, and dyspnea occurred when she was supine and agitated. A right abdominal mass could be palpated on physical examination. Computed tomography and magnetic resonance imaging examinations revealed a large, nonenhanced, cystic and solid mass in the right kidney. The patient received radical nephrectomy for the right kidney. The diagnosis of schwannoma was confirmed by pathological examination.

CONCLUSIONS

We report a case of a large renal schwannoma with obvious hemorrhage and cystic degeneration, which can be used as a reference for further study.

Hemangiopericytoma of the gingiva - An exemplary differential of a masquerading tumor

Periodontal diseases are unique as a small number lesions appearing as inflammatory in reality are neoplastic in nature, and it is imperative that an accurate diagnosis be rendered to provide the appropriate treatment and management. One of the most common clinical presentations of gingival lesions is pedunculated soft-tissue swellings. We report the case of a 63-year-old female who presented with a painless swelling on the interdental papilla of 23 and 24 with a history of recurrences. The lesion was excised by wide surgical excision. This article presents a unique case of a vascular tumor that had clinically mimicked a reactive lesion and with detailed history, thorough clinical examination had provided clues to a vascular entity namely hemangiopericytoma which was confirmed by histological diagnosis. Oral lesions, particularly occurring in gingiva, most often appear clinically benign or innocuous thus necessitating the need for careful examination with investigations to render a diagnosis.

[Histological, immunohistochemical and molecular study of a paratesticular dedifferentiated liposarcoma with inflammatory myofibroblastic tumor-like features]

We report the histological, immunohistochemical, and molecular findings of a dedifferentiated liposarcoma with inflammatory myofibroblastic tumor-like features occurring in the paratesticular region. Histologically, the dedifferentiated component closely resembled an inflammatory myofibroblastic tumor. The neoplastic cells were positive for smooth muscle actin with focal CD56, CD99, Bcl2 and EMA expression. WT1, calretinin, myogenin, CK(AE1/AE3), desmin, H-caldesmon, CD34, ALK, CKIT, DOG1, MUC4 and STAT6 were negative. MDM2 showed diffuse and strong nuclear positivity in neoplastic cells and fluorescence in situ hybridization (FISH) revealed amplified MDM2 (high level) but no SYT rearrangement. Although a lipomatous component was evident macroscopically, well-differentiated liposarcomatous components were not evident in the section examined. Dedifferentiated liposarcoma can have prominent inflammatory myofibroblastic tumor-like features. Pathologists should be aware of this histological variant in order to avoid misdiagnosing dedifferentiated liposarcoma as inflammatory myofibroblastic tumor or other spindle cell tumors which have different behavioral patterns and treatment requirements.

A Comprehensive Understanding of the Genomic Bone Tumor Landscape: A Multicenter Prospective Study

Complexity and heterogeneity increases the difficulty of diagnosis and treatment of bone tumors. We aimed to identify the mutational characterization and potential biomarkers of bone tumors. In this study, a total of 357 bone tumor patients were recruited and the next generation sequencing (NGS)-based YuanSu450 panel, that includes both DNA and RNA sequencing, was performed for genomic alteration identification. The most common mutated genes in bone tumors included TP53, NCOR1, VEGFA, RB1, CCND3, CDKN2A, GID4, CCNE1, TERT, and MAP2K4. The amplification of genes such as NCOR1, VEGFA, and CCND3 mainly occurred in osteosarcoma. Germline mutation analysis reveal a high frequency of HRD related mutations (46.4%, 13/28) in this cohort. With the assistance of RNA sequencing, 16.8% (19/113) gene fusions were independently detected in 20% (16/79) of patients. Nearly 34.2% of patients harbored actionable targeted mutations, of which the most common mutation is CDKN2A deletion. The different mutational characterizations between juvenile patients and adult patients indicated the potential effect of age in bone tumor treatment. According to the genomic alterations, the diagnosis of 26 (7.28%) bone tumors were corrected. The most easily misdiagnosed bone tumor included malignant giant cell tumors of bone (2.8%, 10/357) and fibrous dysplasia of bone (1.7%, 6/357). Meanwhile, we found that the mutations of MUC16 may be a potential biomarker for the diagnosis of mesenchymal chondrosarcomas. Our results indicated that RNA sequencing effectively complements DNA sequencing and increased the detection rate of gene fusions, supporting that NGS technology can effectively assist the diagnosis of bone tumors.

Sarcoma of unknown primary: myth or reality?

BACKGROUND

Sarcoma of unknown primary (SUP) designates an enigmatic entity with histologic confirmation of a metastatic tumor without an identifiable primary after a thorough diagnostic workup. The term "unknown primary" is heavily debatable given that sarcomas can arise from any tissue that harbors its histological structure. In this review, we discuss the validity of SUP as a distinct entity. Medline/PubMed and Google Scholar were searched from 1990 until April 2020 for publications in the English language reporting on SUP. We excluded articles reporting on cases with sarcomas from known organ sites such as lung or uterine sarcomas as well as synovial sarcomas. The Kaplan-Meier method was used to compute the median overall survival. A total of 26 patients with SUP were identified. The median age at diagnosis was 17.5 years with a similar prevalence among men and women. The tumors most commonly reported were alveolar rhabdomyosarcoma and rhabdomyosarcoma not otherwise specified. Almost two-thirds of the patients were reported to have more than one metastatic site. Among the 13 patients with survival data, the median overall survival was 10.0 months. Two patients underwent autopsy and had their primary culprit identified in the chest wall and paravertebral.

CONCLUSIONS

This review showed that SUP shares with sarcomas of known primary similar clinical features including an aggressive clinical course, generally poor response to chemotherapy, and dismal patient outcomes. Thus, SUP does not appear to display a different natural history and biological properties that would allude to a distinct entity.

Primary High-Grade Myxoid Liposarcoma of the Extremities: Prognostic Factors and Metastatic Pattern

(1) Background: This retrospective study aimed to analyze the history and treatment outcomes of localized, high-grade MLS of the extremities. (2) Methods: We retrospectively reviewed 82 patients with primary high-grade MLS of the extremities. OS, LRFS, MFS, PRS, and DFS were analyzed. (3) Results: Five-year OS and LRS were 96% (95% CI: 86-98) and 94% (95% CI: 85-98), respectively. Statistical analysis indicated no risk factors for OS and LFRS. MFS was 77% (65-85) at 5-year follow-up. Size (p = 0.0337) was the only risk factor statistically significant for MFS (HR = 0.248, 95% CI: 0.07-0.84). Median PRS after distant metastasis was 34 months (range: 1-127 months). Five-year PRS was 79% (48-93). Overall, the 5-year DFS was 76% (65-85). (4) Conclusions: Patients with MLS were found to have a good prognosis. In high-grade deep-seated tumors, common risk factors for MLS do not correlate with survival. Tumor size appears to be the only predictor of long-term DSF and MSF.

Intraosseous rhabdomyosarcoma of the maxilla with TFCP2 fusion: A rare aggressive subtype with predilection for the gnathic bones

Rhabdomyosarcomas (RMS) are malignant tumors with skeletal muscle differentiation extremely rare in intraosseous sites. We reported a rare case of an aggressive intraosseous RMS found in the maxilla of a 17-year-old female patient with five months of evolution. Computed tomography revealed a large osteolytic lesion extending from tooth 21 to 27, causing buccal and lingual cortical plate perforation. Microscopically, the lesion showed a proliferation of spindle-shaped cells with elongated nuclei and eosinophilic cytoplasm, arranged in an interlaced fascicle pattern. The nuclei ranged from vesicular with distinct nucleoli to hyperchromatic. A focal component of plump to epithelioid cells with a moderate amount of eosinophilic cytoplasm was seen at the periphery of the tumor. The immunohistochemical analysis revealed positivity for desmin, MyoD1, and myogenin (scattered cells). S-100, SOX10, HMB45, β-catenin, and CD34 were negative. Ki-67 was positive in 30% of tumor cells. Fluorescence in situ hybridization (FISH) analysis showed the presence of a FUS-TFCP2 fusion. The diagnosis was intraosseous RMS with TFCP2 fusion. Surgical excision followed by chemo- and radiotherapy was carried out; however, the patient died of disease nine months after the treatment. Because of the rarity and non-specific signs and symptoms, the clinical diagnosis of intraosseous RMS is difficult and often overlooked. Therefore, careful histopathological evaluation, supported by immunohistochemical and molecular analysis, is essential to correct diagnosis. Early surgical excision with tumor-free margins and prolonged follow-up are strongly recommended.

A Rare Case Report of Mesenchymal Chondrosarcoma with Pancreatic Metastasis

Background: Mesenchymal chondrosarcoma is a rare but aggressive subtype of sarcoma. The majority of involvement locates in the axial skeleton. Treatment modalities include radical surgery, local radiotherapy, and systemic chemotherapy. However, the long-term survival outcome remains poor. Case presentation: We present the case of a 33-year-old male with a palpable chest wall mass for one year, diagnosed with mesenchymal chondrosarcoma with surgical removal. Later, he had an unusual pancreatic tail tumor as the first presentation of disease metastasis which was proven by surgical resection one year later. Conclusion: Although mesenchymal chondrosarcoma locates mainly in the axial skeletal system, extra-skeletal soft tissue or organ involvement might be seen occasionally. Active surveillance with multidisciplinary team management could significantly prolong survival outcomes.

Time and Accuracy to Establish the Diagnosis of Soft Tissue Tumors: A Comparative Analysis from the Swiss Sarcoma Network

Soft tissue tumors are rare tumors, and their histological examination remains a challenge. The establishment of the correct initial histopathologic diagnosis is critical. However, due to the rarity of soft tissue and bone tumors and the inherent difficulty of their classification and diagnostics, discrepancies may occur in up to one third of cases. For these reasons, several studies recommend the involvement of experienced pathologists frequently performing sarcoma diagnostics. Until now, there is only scarce information about how long it takes to establish a correct sarcoma diagnosis. We thus analyzed all consecutive patients presented to the Swiss Sarcoma Network Tumor Board (SSN-MDT/SB) with a primary diagnosis of a soft tissue tumor over a 2-year period (01/2019 to 12/2020) based on a tumor biopsy. We then compared the final histopathological diagnosis of two comparable institutions with similar case load, but different workflows: (i) institution A, with an initial diagnosis performed by a local pathologist, and reviewed by a reference pathologist, and (ii) institution B, with the final diagnosis performed directly by a reference pathologist. In addition, we analyzed the time from biopsy to establishment of the diagnosis. A total of 347 cases were analyzed, 196 from institution A, and 149 from institution B. In 77.6% of the cases, the diagnosis from the local pathologist was concordant with the expert review. Minor discrepancies were found in 10.2% of the cases without any consecutive changes in treatment strategy. In the remaining 12.2% of the cases, there were major discrepancies which influenced the treatment strategy directly. Establishing the final report took significantly longer in institution A (4.7 working days) than in institution B (3.3 working days; p < 0.01). Our results confirm the importance of a pathological second review by a reference pathologist. We recommend direct analysis by experts, as diagnoses can be made more accurately and quickly. Within the SSN, establishing the sarcoma diagnosis is overall accurate and quick but still can be improved.

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 5^th 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.

Update of pediatric soft tissue tumors with review of conventional MRI appearance-part 1: tumor-like lesions, adipocytic tumors, fibroblastic and myofibroblastic tumors, and perivascular tumors

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.

Infantile myofibromatosis: Excellent prognosis but also rare fatal progressive disease. Treatment results of five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry

BACKGROUND

Infantile myofibromatosis (IM) is a rare benign soft tissue tumor and often a self-limiting disease but rarely includes life-threatening complications. Little is known about optimal treatment of primary localized (LD) and multifocal disease (MFD).

METHODS

Treatment and outcome of 95 children with IM registered within five Cooperative Weichteilsarkom Studiengruppe (CWS) trials and one registry (1981-2016) were evaluated.

RESULTS

LD was diagnosed in 71 patients at a median age of 0.4 years (range 0.0-17.7). MFD was present in 24 patients. The mainstay of treatment was watch-and-wait strategy (w&w) after initial biopsy or resection. Low-dose chemotherapy (CHT) was administered to 16/71 (23%) patients with LD and eight of 24 (33%) patients with MFD, imatinib was added in two. A delayed resection was possible in eight of 71 (11%) and five of 24 (21%) patients with LD and MFD, respectively. Overall, patients were alive in complete remission (n = 77) and partial remission (n = 10) at a median follow-up time of 3.4 years after diagnosis (range 0.01-19.4); no data available (n = 5). Three patients died of progressive disease (PD) despite CHT. Gender, tumor size, and location correlated with a favorable event-free survival (EFS) in patients with LD. The 5-year EFS and overall survival of patients with LD were 73% (±12, confidence interval [CI] 95%) and 95% (±6, CI 95%), respectively; for MFD 51% (±22, CI 95%) and 95% (±10, CI 95%).

CONCLUSION

Prognosis is excellent in patients with LD and MFD. Targeted treatment needs to be evaluated for rare fatal PD.

CircRNA-miRNA networks in regulating bone disease

Circular RNA (circRNA) is a class of endogenous noncoding RNA (ncRNA), presenting as a special covalent closed loop without a 5' cap or 3' tail, maintaining resistance to RNA exonuclease and keeping high stability. Although lowly expressed in most situations, circRNA makes an active difference in regulating physiological or pathological processes by modulating gene expression by regulation of transcription, protein, and miRNA functions through various mechanisms in particular tissues. Recent studies have demonstrated the roles of the miRNA-circRNA network in the development of several bone diseases such as osteoporosis, a multiple-mechanism disease resulting from defective bone quality and low bone mass, osteoarthritis, whose main pathomechanism is inflammation and articular cartilage degradation, as well as osteosarcoma, known as one of the most common bone cancers. However, the specific mechanism of how circRNA along with miRNA influences those diseases is not well documented, showing potential for the development of new therapies for those bone diseases.

Primary extra-skeletal Ewing's sarcoma presenting as an epidural Soft Tissue Lesion causing cauda equina syndrome in an adolescent girl: a case report

INTRODUCTION

Primary epidural Ewing's sarcoma in the lumbar spinal canal is a rare condition and very few cases are reported in the literature.

CASE REPORT

A fifteen-year-old girl presented with low backache associated with sudden onset of weakness and radiculopathy of both lower limbs for 10 days, bowel and bladder involvement for 3 days. Physical examination revealed grade 0/5 power and absent sensations below L4 dermatomal level and perianal region (ASIA A). Plantar reflex was mute bilaterally. Magnetic resonance imaging revealed an extradural lesion within the spinal canal at the L3-L4 level. The patient underwent an emergency posterior decompression, extradural lesion excision and instrumented stabilization L3-L5. Based on histopathological examination of the tissue specimen, we diagnosed the lesion as Ewing sarcoma.

DISCUSSION

Primary extra-skeletal Ewing's sarcoma presenting as an epidural lesion in the lumbar spine is a rare clinical entity that should be considered as a differential for spinal epidural lesions. Treatment for such cases is almost always an early surgical intervention due to its rapid onset and compressive neurological symptoms. Wide decompression with instrumented fusion and excision of the lesion followed by chemo and radiotherapy are recommended.

Primary Pulmonary Alveolar Rhabdomyosarcoma in a Pediatric Patient: A Case Report With Literature Review

Rhabdomyosarcoma (RMS) is a rare soft tissue tumor originating from skeletal muscle that is mostly reported in children. The most common sites of involvement are the head, neck, and extremities. The 2020 WHO classification divide RMS into four types: embryonal, alveolar, pleomorphic, and spindle cell/sclerosing. Reports of RMS with primary lung origin are rare. We present a case of RMS in a 16-month-old boy who presented with a lung mass and microscopic examination with fluorescence in situ hybridization confirmed the diagnosis of alveolar RMS. In conclusion, RMS should be considered in the differential diagnosis of any lung mass with small round blue cell morphology in the microscopic evaluation and should be distinguished from metastatic RMS of other sites, pleuropulmonary blastoma, lymphoma, neuroblastoma, primitive neuroectodermal tumor (PNET)/EWING, and malignant peripheral nerve sheet tumors (MPNST).

Primary liposarcoma of the omentum: A case report

RATIONALE

Omental liposarcoma is extremely rare, and only a few reports have been published in the literature. Due to the rarity of the disease, establishing a clear diagnosis and formulating a treatment plan may be challenging for clinicians.

PATIENT CONCERNS

The patient was a 51-year-old woman who presented with a protruding mass and pain in the lower abdomen.

DIAGNOSIS

Magnetic resonance imaging revealed a tumor measuring 15 cm in diameter in the pelvis. Ovarian cancer was suspected based on pre-operative imaging findings.

INTERVENTIONS

An exploratory laparotomy was performed. Intra-operative analysis of the frozen section suggested a benign tumor.

OUTCOMES

Postoperative histopathological analysis confirmed the diagnosis of omental liposarcoma. The patient recovered well after surgery.

LESSON

This case report helps clinical oncologists to develop a comprehensive understanding of this disease and treat it accordingly.

Metastasis of the abdominal wall in a patient with diagnosis of pulmonary adenocarcinoma: An interesting finding

Tumors of the abdominal wall are rare, divided into benign and malignant lesions that are composed of primary tumors and by the parietal invasion of intra-abdominal tumors and metastatic parietal implants. In the case of metastases in the abdominal wall, the most frequent are metastases from neoplasms of colonic origin. The case described below is that of a 68-year-old patient with a history of stage IIA left lung adenocarcinoma who received partial response radiotherapy with an indication for chemotherapy, which she refused and lost follow-up.

Epigenetic modulation in sensitizing metastatic sarcomas to therapies and overcoming resistance

Sarcomas are a class of rare malignancies of mesenchymal origin with a heterogeneous histological spectrum. They are classically associated with poor outcomes, especially once metastasized. A path to improving clinical outcomes may be made through modifying the epigenome, where a variety of sarcomas demonstrate changes that contribute to their oncogenic phenotypes. This Perspective article identifies and describes changes in the sarcoma genome, while discussing specific epigenetic changes and their effect on clinical outcomes. Clinical attempts at modulating epigenetics in sarcoma are reviewed, as well as potential implications of these studies. Epigenetic targets to reverse and delay chemotherapy resistance are discussed. Future directions with primary next steps are proposed to invigorate the current understanding of epigenetic biomarkers to enact targeted therapies to epigenetic phenotypes of sarcoma subtypes. Modifications to prior studies, as well as proposed clinical steps, are also addressed.

Establishment of A Nomogram for Predicting the Prognosis of Soft Tissue Sarcoma Based on Seven Glycolysis-Related Gene Risk Score

Background: Soft tissue sarcoma (STS) is a group of tumors with a low incidence and a complex type. Therefore, it is an arduous task to accurately diagnose and treat them. Glycolysis-related genes are closely related to tumor progression and metastasis. Hence, our study is dedicated to the development of risk characteristics and nomograms based on glycolysis-related genes to assess the survival possibility of patients with STS.

Methods: All data sets used in our research include gene expression data and clinical medical characteristics in the Genomic Data Commons Data Portal (National Cancer Institute) Soft Tissue Sarcoma (TCGA SARC) and GEO database, gene sequence data of corresponding non-diseased human tissues in the Genotype Tissue Expression (GTEx).Next, transcriptome data in TCGA SARC was analyzed as the training set to construct a glycolysis-related gene risk signature and nomogram, which were confirmed in external test set.

Results: We identified and verified the 7 glycolysis-related gene signature that is highly correlated with the overall survival (OS) of STS patients, which performed excellently in the evaluation of the size of AUC, and calibration curve. As well as, the results of the analysis of univariate and multivariate Cox regression demonstrated that this 7 glycolysis-related gene characteristic acts independently as an influence predictor for STS patients. Therefore, a prognostic-related nomogram combing 7 gene signature with clinical influencing features was constructed to predict OS of patients with STS in the training set that demonstrated strong predictive values for survival.

Conclusion: These results demonstrate that both glycolysis-related gene risk signature and nomogram were efficient prognostic indicators for patients with STS. These findings may contribute to make individualize clinical decisions on prognosis and treatment.

Glomus Tumor of the Kidney Harboring Malignant Potential

Glomus tumors are rare, benign, vascular neoplasms arising from the glomus body. Although they occasionally develop in any part of the body, they do so more common in the upper extremities, most frequently subungual areas. An extensive review of the literature revealed less than thirty cases of primary renal glomus tumors. We present a unique case of an adult male with an incidentally discovered 2.5 cm right renal mass. Histopathologic and immunohistochemical examination suggested the diagnosis of glomus tumor. Based on the World Health Organization (WHO) classification of soft tissue tumors, the presence of at least two atypical features indicates malignant potential. In this case, deep/visceral location and size greater than 2 cm fulfilled these criteria. Following an uneventful excision and a 12-month follow-up period, the patient remains disease-free with no sign of local or distant metastases.

Solitary fibrous tumors: Clinical and imaging features from head to toe

Solitary fibrous tumors (SFTs) are rare fibroblastic mesenchymal tumors that are usually benign with variable malignant potential. They can develop in any organ due to their spindle cell origin. The exact etiology of solitary fibrous tumors is unknown. The majority of SFTs are benign with 10-30% of them exhibiting aggressive and malignant features. The aggressiveness of this type of tumor is not associated with its histological features, which makes surgical resection the treatment of choice. We will review the clinical and radiological features and possible differential diagnoses of SFTs according to their anatomical sites following the World Health Organization 2020 classification.

Update on MR Imaging of Soft Tissue Tumors of Head and Neck

This article reviews soft tissue tumors of the head and neck following the 2020 revision of WHO Classification of Soft Tissue and Bone Tumours. Common soft tissue tumors in the head and neck and tumors are discussed, along with newly added entities to the classification system. Salient clinical and imaging features that may allow for improved diagnostic accuracy or to narrow the imaging differential diagnosis are covered. Advanced imaging techniques are discussed, with a focus on diffusion-weighted and dynamic contrast imaging and their potential to help characterize soft tissue tumors and aid in distinguishing malignant from benign tumors.

Characterization of cannabinoid receptors expressed in Ewing sarcoma TC-71 and A-673 cells as potential targets for anti-cancer drug development

AIMS

Characterizing cannabinoid receptors (CBRs) expressed in Ewing sarcoma (EWS) cell lines as potential targets for anti-cancer drug development.

MAIN METHODS

CBR affinity and function were examined by competitive binding and G-protein activation, respectively. Cannabinoid-mediated cytotoxicity and cell viability were evaluated by LDH, and trypan blue assays, respectively.

KEY FINDINGS

qRT-PCR detected CB1 (CB1R) and CB2 receptor (CB2R) mRNA in TC-71 cells. However, binding screens revealed that CBRs expressed exhibit atypical properties relative to canonical receptors, because specific binding in TC-71 could only be demonstrated by the established non-selective CB1/CB2R radioligand [³H]WIN-55,212-2, but not CB1/CB2R radioligand [³H]CP-55,940. Homologous receptor binding demonstrated that [³H]WIN-55,212-2 binds to a single site with nanomolar affinity, expressed at high density. Further support for non-canonical CBRs expression is provided by subsequent binding screens, revealing that only 9 out of 28 well-characterized cannabinoids with high affinity for canonical CB1 and/or CB2Rs were able to displace [³H]WIN-55,212-2, whereas two ligands enhanced [³H]WIN-55,212-2 binding. Five cannabinoids producing the greatest [³H]WIN-55,212-2 displacement exhibited high nanomolar affinity (K_i) for expressed receptors. G-protein modulation and adenylyl cyclase assays further indicate that these CBRs exhibit distinct signaling/functional profiles compared to canonical CBRs. Importantly, cannabinoids with the highest affinity for non-canonical CBRs reduced TC-71 viability and induced cytotoxicity in a time-dependent manner. Studies in a second EWS cell line (A-673) showed similar atypical binding properties of expressed CBRs, and cannabinoid treatment produced cytotoxicity.

SIGNIFICANCE

Cannabinoids induce cytotoxicity in EWS cell lines via non-canonical CBRs, which might be a potential therapeutic target to treat EWS.

Common Pitfalls in Ewing Sarcoma and Desmoplastic Small Round Cell Tumor Diagnosis Seen in a Study of 115 Cases

Ewing sarcoma (ES), “Ewing-like sarcoma” (ELS) and desmoplastic small round cell tumors (DSRCT) can masquerade as other tumor types, particularly neuroendocrine neoplasms and receive inappropriate treatment. We retrieved 115 cases of ES, ELS and DSRCT seen over 17 years in a tertiary center. An initial misdiagnosis or incomplete diagnosis occurred in 6/93 (6.4%) of ES/ELS and 5/22 (22.7%) of DSRCT cases. The most frequent misdiagnosis was small cell neuroendocrine carcinoma. While any misdiagnosis or incomplete classification is almost certainly multifactorial, the most common identified reason for erroneous/incomplete initial reporting was expression of neuroendocrine markers. Other contributing factors included keratin expression, older patient age and apparently unusual tumor location. Most patients treated with a non-sarcoma chemotherapy regimen expired, while those who received a sarcoma-related regimen were alive as of last evaluation. Increased awareness of this diagnostic pitfall is needed in evaluating cases of round cell malignancies.

t(4;12)(q12;p13) ETV6-rearranged AML without eosinophilia does not involve PDGFRA: relevance for imatinib insensitivity

Apparent ETV6-PDGFRA fusions identified by FISH analysis in t(4;12)(q12;p13) AML should be confirmed by sequencing.

Sequence-confirmed ETV6-PDGFRA fusions have not been identified in patients with t(4;12)(q12;p13) AML without eosinophilia.

Acute myeloid leukemia (AML) with t(4;12)(q12;p13) translocation is rare and often associated with an aggressive clinical course and poor prognosis. Previous reports based on fluorescence in situ hybridization (FISH) analysis have suggested that ETV6::PDGFRA fusions are present in these patients, despite the absence of eosinophilia, which is typically found in other hematopoietic malignancies with PDGFRA-containing fusions. We first detected an ETV6-SCFD2 fusion by targeted RNA sequencing in a patient with t(4;12)(q12;p13) who had been diagnosed with an ETV6-PDGFRA fusion by FISH analysis but failed to respond to imatinib. We then retrospectively identified 4 additional patients with AML and t(4;12)(q12;p13) with apparent ETV6-PDGFRA fusions using chromosome and FISH analysis and applied targeted RNA sequencing to archival material. We again detected rearrangements between ETV6 and non-PDGFRA 4q12 genes, including SCFD2, CHIC2, and GSX2. None of the 3 patients who received imatinib based on the incorrect assumption of an ETV6-PDGFRA fusion responded. Our findings highlight the importance of using a sequencing-based assay to confirm the presence of targetable gene fusions, particularly in genomic regions, such as 4q12, with many clinically relevant genes that are too close to resolve by chromosome or FISH analysis. Finally, combining our data and review of the literature, we show that sequence-confirmed ETV6-PDGFRA fusions are typically found in eosinophilic disorders (3/3 cases), and patients with t(4;12)(q12;p13) without eosinophilia are found to have other 4q12 partners on sequencing (17/17 cases).

Long non-coding RNA miR155HG silencing restrains ovarian cancer progression by targeting the microRNA-155-5p/tyrosinase-related protein 1 axis

Ovarian cancer (OC) is the third commonest gynecological malignancy worldwide. The long non-coding (lnc)RNA microRNA (miR)155HG functions as an oncogene in different human cancers. However, the function and molecular mechanism of miR155HG in OC remain elusive. The present study indicated that the expression levels of miR155HG and tyrosinase-related protein 1 (TYRP1) were significantly increased, whereas that of miR155-5p was decreased in OC tissues and cells, as detected by real-time quantitative polymerase chain reaction. It was demonstrated that knockdown of miR155HG markedly inhibited OC cell viability, migration and invasion while promoting apoptosis, as indicated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound healing, Transwell and western blot assays. Mechanistically, it was revealed that miR155HG and TYRP1 were both targeted by miR-155-5p with complementary binding sites in the 3' untranslated region. A dual-luciferase reporter assay was used to confirm the targeting relationship between miR155HG, miR-155-5p and TYRP1. In addition, the interaction between miR155HG and miR-155-5p was further demonstrated by radioimmunoprecipitation and pull-down assays. In addition, feedback approaches determined that miR-155-5p inhibition or TYRP1 overexpression markedly reversed the inhibitory effects of miR155HG knockdown on OC cell viability, migration and invasion as well as weakened the promotive effect of miR155HG knockdown on OC cell apoptosis. Thus, miR155HG silencing inhibited the malignant biological behavior of OC cells by targeting the miR-155-5p/TYRP1 axis. The present study provides novel insights into the underlying mechanism of OC progression.

Undifferentiated Small Round Cell Sarcoma of the Postcricoid Region of the Hypopharynx: A Rare Case Report and Review of the Literature

Undifferentiated small round cell sarcoma (USRCS) is a rare malignant tumor. No reports about USRCS of the postcricoid region of the hypopharynx are available, and its clinical features and treatment guidelines remain undefined. We report a case of USRCS of the postcricoid region of the hypopharynx with treatment of surgery and radiotherapy. A 50-year-old man presented with a 4.9 cm x 3.7 cm tumor in the postcricoid region of the hypopharynx. It was diagnosed as USRCS. The tumor showed small round cells and positive immunoexpression of CD56, Cyclin D1, TLE1 and CD99, but no rearrangement or fusion of EWSR1, SS18, CIC, and BCOR. The patient underwent radiotherapy after surgery, without signs of tumor progression and metastasis at the 9-month follow-up. In conclusion, USRCS of postcricoid region of hypopharyngeal is ultra-rare. To make diagnosis, pathological examination is necessary. Surgery followed by radiotherapy might offer an optional treatment for USCRS.

Oral epithelioid rhabdomyosarcoma: Report of a rare case and literature review of a distinct variant of rhabdomyosarcoma

Epithelioid rhabdomyosarcoma is a new and rare morphological variant of rhabdomyosarcoma, with only a few reports in the literature. We aimed to describe an atypical case of this variant involving the oral cavity. A 33-year-old male patient presented with an asymptomatic, gingival mass adjacent to the left maxillary canine with progressive growth over approximately 3 months. Microscopic and immunohistochemical assessment of the biopsy specimen were consistent with epithelioid rhabdomyosarcoma. After initial chemotherapy and radiotherapy, the patient had a partial response. Surgical resection was performed, followed by adjuvant chemotherapy. After local and distant recurrences, the patient died 22 months after the initial diagnosis. According to the literature, epithelioid rhabdomyosarcoma still lacks data regarding its aetiologic factors and therapeutic options. Whether this tumour is a true subtype or simply a variant of other subtypes of rhabdomyosarcoma also remains unconfirmed. Final diagnosis leads to a broad array of microscopic and immunohistochemical analyses.

Protein Arginine Methyltransferase (PRMT) Inhibitors-AMI-1 and SAH Are Effective in Attenuating Rhabdomyosarcoma Growth and Proliferation in Cell Cultures

Rhabdomyosarcoma (RMS) is a malignant soft tissue cancer that develops mostly in children and young adults. With regard to histopathology, four rhabdomyosarcoma types are distinguishable: embryonal, alveolar, pleomorphic and spindle/sclerosing. Currently, increased amounts of evidence indicate that not only gene mutations, but also epigenetic modifications may be involved in the development of RMS. Epigenomic changes regulate the chromatin architecture and affect the interaction between DNA strands, histones and chromatin binding proteins, thus, are able to control gene expression. The main aim of the study was to assess the role of protein arginine methyltransferases (PRMT) in the cellular biology of rhabdomyosarcoma. In the study we used two pan-inhibitors of PRMT, called AMI-1 and SAH, and evaluated their effects on proliferation and apoptosis of RMS cells. We observed that AMI-1 and SAH reduce the invasive phenotype of rhabdomyosarcoma cells by decreasing their proliferation rate, cell viability and ability to form cell colonies. In addition, microarray analysis revealed that these inhibitors attenuate the activity of the PI3K-Akt signaling pathway and affect expression of genes related to it.

Primary angiosarcoma of aorta: A systematic review

PURPOSE

To elucidate the epidemiology, anatomical, presentation, classification, pathology, investigative modalities, management and prognosis of primary angiosarcoma of the aorta.

MATERIAL AND METHODS

A systematic review of literature from the database inception to January 2021 in PubMed and Embase, CINAHL and Cochrane Library in accordance to PRISMA was conducted. Retrieval and extraction was performed by two independent reviewers. The hierarchy of the evidence was assessed through the National Institute for Health and Care Excellence Checklist. Data were subjected to pooled prevalence analysis, Kaplan-Meier survival and test of probability using log-rank analysis. This review is registered with International Prospective Register of Systematic Reviews: RD42021231314.

RESULTS

82 studies with n = 123 cases met the inclusion criterion. Abdominal (45%) aorta was the commonest anatomical site with female predominance in ascending aorta (4:1) and aortic arch (2:1). The longest survival was in the ascending aorta and the shortest in the abdominal aorta [540 (interquartile range [IQR], 7-1560 days vs. 180 (IQR, 1-5730 days)], respectively. The overall median survival was 210 days (IQR, 1-5730 days) or 7 months. Lack of metastasis (47%) was a marker of longer survival (p < 0.03) irrespective of other attributes.

CONCLUSION

The pathophysiology appears to be a trend of increasing fatigue, fever and weight loss associated with segmental dysfunction of the aorta projecting occlusive or destructive phenotypes. Computed tomography angiography features of volume-occupying, bulky, polypoid (intraluminal), protrusive vegetation, hyper vascular without atherosclerotic lesions are extremely suggestive of PA of the aorta at 5th and 6th decades of life.

Soft Tissue Sarcoma: An Insight on Biomarkers at Molecular, Metabolic and Cellular Level

Simple Summary

Soft tissue sarcoma is a rare mesenchymal malignancy. Despite the advancements in the fields of radiology, pathology and surgery, these tumors often recur locally and/or with metastatic disease. STS is considered to be a diagnostic challenge due to the large variety of histological subtypes with clinical and histopathological characteristics which are not always distinct. One of the important clinical problems is a lack of useful biomarkers. Therefore, the discovery of biomarkers that can be used to detect tumors or predict tumor response to chemotherapy or radiotherapy could help clinicians provide more effective clinical management.

Abstract

Soft tissue sarcomas (STSs) are a heterogeneous group of rare tumors. Although constituting only 1% of all human malignancies, STSs represent the second most common type of solid tumors in children and adolescents and comprise an important group of secondary malignancies. Over 100 histologic subtypes have been characterized to date (occurring predominantly in the trunk, extremity, and retroperitoneum), and many more are being discovered due to molecular profiling. STS mortality remains high, despite adjuvant chemotherapy. New prognostic stratification markers are needed to help identify patients at risk of recurrence and possibly apply more intensive or novel treatments. Recent scientific advancements have enabled a more precise molecular characterization of sarcoma subtypes and revealed novel therapeutic targets and prognostic/predictive biomarkers. This review aims at providing a comprehensive overview of the most relevant cellular, molecular and metabolic biomarkers for STS, and highlight advances in STS-related biomarker research.

Schwannoma of the abdominal wall: updated literature review

Background

Schwannoma is a benign tumor arising from Schwann cells of the peripheral nerves. It is often asymptomatic and can develop in the retroperitoneum, mediastinum, head and neck region, and upper and lower extremities. Schwannoma of the abdominal wall is extremely rare, but differential diagnosis with malignant neoplasms is important to reduce the risk of undertreatment.

Methods

A narrative review of abdominal wall schwannoma was performed using PubMed, EMBASE, and Web of Science database and the search terms “schwannoma”, “neurinoma”, “neurilemmoma”, “soft tissue tumors”, “neurogenic tumor”, “rectus abdominis mass”, “abdominal wall”. In addition, the hospital charts were reviewed to report the personal experience.

Results

Only 9 single case-reports of benign schwannoma of the abdominal wall were found in the English medical literature over the past decade. None of the patients received preoperative biopsy and all were resected with clear margins. In addition to the literature review, we report the case of a 58-year-old man referred for a palpable mass in the left upper abdominal quadrant. Ultrasonography and magnetic resonance imaging revealed a solid and well-encapsulated mass inside the left rectus abdominis muscle. A core biopsy of the lesion provided the diagnosis of cellular schwannoma and this was confirmed by histopathologic examination of the surgical specimen.

Conclusions

Benign schwannoma of the abdominal wall is extremely rare. Percutaneous core needle biopsy is important for the differential diagnosis with more common and biologically more aggressive malignancies, such as desmoid tumors and sarcomas, and may be relevant for planning the most appropriate management.

[Adult non-Hodgkin bone lymphomas]

Two forms of bone lymphomas can be distinguished: the primary bone lymphoma (PBL) and the secondary bone lymphoma (SBL). PBL is a rare disease with a good prognosis. Clinical manifestations and imaging findings are usually non-specific. Patient can present with pain, swelling of affected bone or pathologic fracture. Positron emission tomography-CT scan is a sensitive imaging modality and very useful for staging, restaging, surveillance of recurrence, and monitoring of treatment response of lymphoma. The diagnosis of PBL is often difficult and made after biopsy examination. Most patients have diffuse large B-cell lymphoma. Patients have been treated with radiotherapy, chemotherapy or combination of both. Localized disease, low IPI (International Prognostic Index) and complete remission after initial treatment were associated with a better outcome. Management of late sequelae deserves particular attention. SBL is more common than PBL; this is a disseminated lymphoma with concomitant involvement of the skeleton. We review the clinical, imaging and pathologic features of bone lymphomas; and discuss therapeutic modalities as well as prognosis of these lymphomas in the era of immunochemotherapy.

Pathogenesis and Current Treatment of Osteosarcoma: Perspectives for Future Therapies

Osteosarcoma is the most common primary malignant bone tumor in children and young adults. The standard-of-care curative treatment for osteosarcoma utilizes doxorubicin, cisplatin, and high-dose methotrexate, a standard that has not changed in more than 40 years. The development of patient-specific therapies requires an in-depth understanding of the unique genetics and biology of the tumor. Here, we discuss the role of normal bone biology in osteosarcomagenesis, highlighting the factors that drive normal osteoblast production, as well as abnormal osteosarcoma development. We then describe the pathology and current standard of care of osteosarcoma. Given the complex heterogeneity of osteosarcoma tumors, we explore the development of novel therapeutics for osteosarcoma that encompass a series of molecular targets. This analysis of pathogenic mechanisms will shed light on promising avenues for future therapeutic research in osteosarcoma.

Primary dedifferentiated Liposarcoma of vagina: a first case report

BACKGROUND

Dedifferentiated liposarcoma, one of the most deadly types of soft tissue sarcoma, is an aggressive and high-grade form of liposarcoma. Liposarcoma occurs most commonly in the retroperitoneum, extremities and trunk, but less frequently in the female genital tract. The vagina is a very rare site of origin. Herein we report the first case of dedifferentiated Liposarcoma deriving from vagina and discuss its clinical course.

CASE PRESENTATION

A 38-year-old female patient presented to our institution with a painless vaginal mass. Abdominal computed tomography showed a 17.6 cm× 10.4 cm solid mass originating from the right lateral wall of her vagina. Then she underwent complete surgical resection of the tumor mass, and postoperative pathological result confirmed the diagnosis of dedifferentiated liposarcoma deriving from vagina. Six courses of combination chemotherapy with pirarubicin plus ifosfamide were performed after surgery. The patient remains with no evidence of disease recurrence with 13 months of follow-up.

CONCLUSIONS

Liposarcoma is very rare in female genital tract, and more rare for dedifferentiated liposarcoma in gynecologic field. Little is known about the clinical characteristics, pathological diagnosis, prognosis and optimal management strategy of vaginal dedifferentiated liposarcoma. Complete surgical resection followed by systemic chemotherapy is suggested to be standard treatment for dedifferentiated liposarcoma. Combination chemotherapy with pirarubicin and ifosfamide may be effective for treating vaginal dedifferentiated liposarcoma.