Histopathological diagnostic discrepancies in soft tissue tumours referred to a specialist centre: reassessment in the era of ancillary molecular diagnosis

ASO Practice Guidelines Series: Multidisciplinary Management of Retroperitoneal Sarcomas

Retroperitoneal sarcomas (RPS) represent a rare and biologically diverse group of malignancies, distinct from soft tissue sarcomas arising in other anatomic regions. Their deep-seated location, large size at presentation and proximity to critical structures contribute to diagnostic delays, treatment challenges, and variable oncologic outcomes, particularly when managed outside high-volume referral centers. Current international guidelines emphasize the importance of preoperative biopsy, review by a sarcoma pathologist, management in a referral center, multidisciplinary case discussion, consideration for clinical trials enrollment, and prospective database inclusion as standards of care. Given that the quality of the initial surgical resection-achieving complete macroscopic resection with margins tailored to the histologic type-remains the most important modifiable prognostic factor, adherence to international best practices in surgical and multimodal treatment is crucial to optimize patient outcomes. This article reviews contemporary management strategies for adult-type RPS, emphasizing the importance of multidisciplinary expertise.

UK guidelines for the management of soft tissue sarcomas

Soft tissue sarcomas (STS) are rare tumours arising in mesenchymal tissues and can occur almost anywhere in the body. Their rarity, and the heterogeneity of subtype and location, means that developing evidence-based guidelines is complicated by the limitations of the data available. This makes it more important that STS are managed by expert multidisciplinary teams, to ensure consistent and optimal treatment, recruitment to clinical trials, and the ongoing accumulation of further data and knowledge. The development of appropriate guidance, by an experienced panel referring to the evidence available, is therefore a useful foundation on which to build progress in the field. These guidelines are an update of the previous versions published in 2010 and 2016 [1, 2]. The original guidelines were drawn up by a panel of UK sarcoma specialists convened under the auspices of the British Sarcoma Group (BSG) and were intended to provide a framework for the multidisciplinary care of patients with soft tissue sarcomas. This iteration of the guidance, as well as updating the general multidisciplinary management of soft tissue sarcoma, includes specific sections relating to the management of sarcomas at defined anatomical sites: gynaecological sarcomas, retroperitoneal sarcomas, breast sarcomas, and skin sarcomas. These are generally managed collaboratively by site specific multidisciplinary teams linked to the regional sarcoma specialist team, as stipulated in the recently published sarcoma service specification [3]. In the UK, any patient with a suspected soft tissue sarcoma should be referred to a specialist regional soft tissues sarcoma service, to be managed by a specialist sarcoma multidisciplinary team. Once the diagnosis has been confirmed using appropriate imaging and a tissue biopsy, the main modality of management is usually surgical excision performed by a specialist surgeon, combined with pre- or post-operative radiotherapy for tumours at higher risk for local recurrence. Systemic anti-cancer therapy (SACT) may be utilised in cases where the histological subtype is considered more sensitive to systemic treatment. Regular follow-up is recommended to assess local control, development of metastatic disease, and any late effects of treatment.

Progress in histology specific treatments in soft tissue sarcoma

INTRODUCTION

Soft tissue sarcomas (STS) represent a heterogenous group of rare tumors, primarily treated with surgery. Preoperative radiotherapy is often recommended for extremity high-risk STS. Neoadjuvant chemotherapy, typically based on doxorubicin with ifosfamide, has shown efficacy in limbs and trunk wall STS. Second-line chemotherapy, commonly utilized in the metastatic setting, is mostly histology-driven. Molecular targeted agents are used across various histologies, and although the use of immunotherapy in STS is still in its early stages, there is increasing interest in exploring its potential.

AREAS COVERED

This article involved an extensive recent search on PubMed. It explored the current treatment landscape for localized and metastatic STS, focusing on the combined use of radiotherapy and chemotherapy for both extremity and retroperitoneal tumors, and with a particular emphasis on the most innovative histopathology driven therapeutic approaches. Additionally, ongoing clinical trials identified via clinicaltrials.gov are included.

EXPERT OPINION

Recently there have been advancements in the treatment of STS, largely driven by the outcomes of clinical trials. However further research is imperative to comprehend the effect of chemotherapy, targeted therapy and immunotherapy in various STS, as well as to identify biomarkers able to predict which patients are most likely to benefit from these treatments.

Primary Retrovesical Leiomyosarcoma: A Case Report

Soft tissue sarcomas (STS) are a rare group of malignant tumors in adults. This group of tumors contains a variety of subtypes, each with distinct clinical features and presentations. Leiomyosarcoma is among the most common subtypes, which typically occur within the uterus, retroperitoneum, abdomen, and large blood vessels. At presentation, tumors are often large and may have metastasized to the lungs, liver, or peritoneum. Given the rarity and variability of the disease, a multidisciplinary treatment approach is essential for management, however, further research is needed to develop histologic-specific guidelines and targeted treatments. Here, we present a case of a 69-year-old male who was found to have a large pelvic mass of unknown etiology after presenting to the emergency department with generalized weakness, decreased appetite, and an inability to ambulate. On examination, he was found to have testicular swelling and trace edema of bilateral lower extremities. Labs significant for lactic acidosis and CT chest/abdomen/pelvis showed a large heterogeneously enhancing mass within the pelvis measuring up to 15 cm x 12 cm x 15 cm, of uncertain origin, but highly concerning for malignancy. Biopsy with immunohistochemical stains of the mass revealed a grade 2 leiomyosarcoma. Due to the size and location of the mass, transfer to a tertiary care center was recommended. Computed tomography angiography (CTA) abdomen/pelvis and magnetic resonance imaging (MRI) abdomen/pelvis performed at the tertiary care hospital revealed a 16.6 cm heterogeneously enhancing, necrotic mass within the retrovesical pelvic space and three liver lesions, which were concerning for metastases. Due to the patient's deconditioning and poor functional status, surgical resection and radiation were not offered. The patient expired soon after his code status was changed to comfort care.

Enhanced accuracy and reduced delay in diagnosing bone tumors within an expert sarcoma network: A nationwide study

INTRODUCTION

Primary bone tumors encompass a range of rare and diverse lesions. Pathological diagnosis poses significant challenges, with histological discrepancies extensively studied in soft tissue sarcomas but lacking specific investigation in bone lesions. This study aimed to determine the rate of major diagnostic discrepancies in primary bone tumors, assessing whether initial histological analysis within an expert referral center network reduces this rate and final diagnostic delay. Additionally, we examined the impact of mandatory systematic re-reading by expert pathologists on diagnostic variation and readjustment.

METHODS

Our study cohort comprised patients with primary bone tumors, drawn from the national prospective French sarcoma network database. A total of 1075 patients were included from 2018 to 2019.

RESULTS

The cohort exhibited a major discrepancy rate of 24%. Within the expert referral centers network, 49 cases (7%) showed major diagnostic discrepancies in the initial analysis, compared to 207 cases (57%) outside the network (p < 0.001). Regarding the final diagnostic delay, a mean of 2.8 weeks (±4.9) was observed within the network, contrasting with 6.5 weeks (±9.1) outside the network (p < 0.001). Systematic re-reading by an expert pathologist facilitated diagnosis readjustment in 75% of the 256 cases, with 68% of all diagnostic variations occurring preoperatively.

CONCLUSION

Early management within the expert network significantly reduced major diagnostic discrepancies and shortened the diagnosis delay by approximately a month. Expert pathologist systematic re-readings were responsible for diagnosis readjustments in three-quarters of cases, with two-thirds of all diagnostic variations occurring preoperatively, thereby mitigating the consequences of mistreatment.

Initial local resection versus early referral for spermatic cord sarcoma: Any impact on treatment timelines and oncological outcomes?

OBJECTIVES

Spermatic cord sarcomas are exceedingly rare, often misdiagnosed and subsequently improperly treated at local hospitals. This retrospective study looked at the oncological outcomes of spermatic cord sarcoma cases managed with curative intent resection at a tertiary referral sarcoma centre. We specifically studied how initial inadequate resections impact the oncologic outcomes compared to primary tumour resections at the reference centre.

METHODS

One hundred eighteen consecutive patients affected by primary, localized spermatic cord sarcoma surgically managed at our reference centre from January 2001 through January 2021 were included. Primary endpoints were local relapse free (LRFS), distant metastasis free (DMFS) and overall survival (OS). These outcomes were evaluated with multi-nomial logistic regression and Cox proportional hazards regression models for a co-relation to known patient, tumour and treatment-related prognostic factors, including a prior inadequate resection and time from diagnosis to a complete oncologic resection as independent variables. Secondarily, we compared the above variables and treatment intervals among the subgroups of primary versus re-resection surgery.

RESULTS

Over a median follow-up of 54 months (IQR 25-105), 12 patients (10.2%) developed local recurrence (LR) and 14 (11.6%) had distant metastasis (DM). 5-year local relapse (LRFS) and distant metastasis-free survival (DMFS) were 89.3% and 86.5%, respectively. Higher tumour grade and size were associated with a worse DMFS (p=<0.05). Likewise, marginal (R1) resection correlated with an inferior LRFS (p=< 0.05). Eighty-four patients (71.2%) had their initial diagnosis established on an inadequate surgical excision performed in a local hospital, followed by a re-excision at our centre (Re-resection group). During the same period, 34 (28.8%) were managed primarily with biopsy and treatment at our reference centre (Primary-resection group). The two groups had statistically significant differences in tumour size, histopathology, surgery duration, rate of postoperative complication and R0 resection (p < 0.005). Additionally, the difference in time intervals to achieve the treatment targets was statistically insignificant and did not correlate to the risk of recurrence as an independent variable. Residual disease was present in 51.2 % (n = 43) of the re-excision specimens. However, following a complete R0 resection, this did not correlate with a higher risk of recurrence (p = 0.481).

CONCLUSION

Prompt referral to a tertiary centre, where multidisciplinary evaluation and sound oncologic resections are the standard of treatment, can align the OS and DFS of patients receiving incomplete surgery elsewhere to those treated primarily in referral centres. The primary determinant of prognosis remains surgical margin, tumour size and grade.

Germline Genetic Mutations in Adult Patients with Sarcoma: Insight into the Middle East Genetic Landscape

Data on germline mutations in soft tissue and bone sarcomas are scarce. We sought to identify the prevalence of germline mutations in adult sarcoma patients treated at a tertiary cancer center. Newly diagnosed patients were offered germline genetic testing via an 84-gene panel. The prevalence of pathogenic germline variants (PGVs) and their association with disease-, and patient- related factors are reported. A total of 87 patients were enrolled, the median age was 48 (19-78) years, and 47 (54%) were females. Gastrointestinal stromal tumors (n = 12, 13.8%), liposarcoma (n = 10, 11.5%), and Ewing sarcoma (n = 10, 11.5%) were the main subtypes. A total of 20 PGVs were detected in 18 (20.7%) patients. Variants of uncertain significance, in the absence of PGVs, were detected in 40 (45.9%) patients. Young age (p = 0.031), presence of a second primary cancer (p = 0.019), and female gender (p = 0.042) were correlated with the presence of PGVs. All identified PGVs have potential clinical actionability and cascade testing, and eight (44.44%) suggested eligibility for a targeted therapy. Almost one in five adult patients with soft tissue and bone sarcomas harbor pathogenic or likely pathogenic variants. Many of these variants are potentially actionable, and almost all have implications on cancer screening and family counselling. In this cohort from the Middle East, younger age, presence of a second primary tumor, and female gender were significantly associated with higher PGVs rates. Larger studies able to correlate treatment outcomes with genetic variants are highly needed.

Challenges and opportunities in rare cancer research in China

Cancer is one of the major public health challenges in China. Rare cancers collectively account for a considerable proportion of all malignancies. The lack of awareness of rare cancers among healthcare professionals and the general public, the typically complex and delayed diagnosis, and limited access to clinical trials are key challenges. Recent years have witnessed an increase in funding for research related to rare cancers in China. In this review, we provide a comprehensive overview of rare cancers and summarize the status of research on rare cancers in China and overseas, including the trends of funding and publications. We also highlight the challenges and perspectives regarding rare cancers in China.

Unplanned Sarcoma Excisions: Understanding How They Happen

BACKGROUND

Soft-tissue sarcomas present as a mass with nonspecific symptoms, and unplanned excisions commonly occur. The purpose of this study was to analyze the incidence of unplanned excisions performed by orthopaedic surgeons and to conduct a root cause analysis (RCA) of the steps that led to unplanned excisions in all the cases.

METHODS

A retrospective case-control study was conducted. Two cohorts were identified, one including patients who underwent an unplanned excision of a soft-tissue sarcoma (n = 107) and a second cohort with patients whose entire care was performed at our sarcoma center (n = 102). A RCA was conducted with the whole sample to identify the preventable causes that led to sarcoma unplanned excisions.

RESULTS

Orthopedic surgeons were the second group of physicians to perform the most unplanned excisions, only behind general surgeons. Inadequate imaging was encountered in 76.6% of the patients (n = 82, 95% confidence interval, 67.8 to 83.6). Forty-five patients (42.1%) had no imaging studies before the unplanned procedure. In the RCA, the most notable obstacles found were (1) incorrect assumption of a benign diagnosis, (2) failure to obtain the appropriate imaging study, (3) incorrectly reported imaging studies, (4) failure to order a biopsy, and (5) incorrect reporting of the biopsy.

CONCLUSIONS

Despite educational efforts, unplanned excisions and the devastating consequences that sometimes follow continue to occur. Orthopaedic surgeons persist in playing a role in the unplanned procedure burden.

Diagnostic Superiority of Dual-Time Point [18F]FDG PET/CT to Differentiate Malignant from Benign Soft Tissue Tumors

[18F]FDG PET/CT is used in the workup of indeterminate soft tissue tumors (STTs) but lacks accuracy in the detection of malignant STTs. The aim of this study is to evaluate whether dual-time point [18F]FDG PET/CT imaging (DTPI) can be useful in this indication. In this prospective study, [18F]FDG PET/CT imaging was performed 1 h (t1) and 3 h (t2) after injection. Tumor uptake (SUVmax) was calculated at each time point to define a retention index (RI) corresponding to the variation between t1 and t2 (%). Sixty-eight patients were included, representing 20 benign and 48 malignant tumors (including 40 sarcomas). The RI was significantly higher in malignant STTs than in benign STTs (median: +21.8% vs. -2%, p < 0.001). An RI of >14.3% predicted STT malignancy with a specificity (Sp) of 90% and a sensitivity (Se) of 69%. An SUVmaxt1 of >4.5 was less accurate with an Sp of 80% and an Se of 60%. In a subgroup of tumors with at least mild [18F]FDG uptake (SUVmax ≥ 3; n = 46), the RI significantly outperformed the diagnostic accuracy of SUVmax (AUC: 0.88 vs. 0.68, p = 0.01). DTPI identifies malignant STT tumors with high specificity and outperforms the diagnostic accuracy of standard PET/CT.

Enhancing Healthcare for Sarcoma Patients: Lessons from a Diagnostic Pathway Efficiency Analysis

Sarcomas, rare and with lower survival rates than common tumors, offer insights into healthcare efficiency via the analysis of the total interval of the diagnostic pathway, combining the patient interval (time between the first symptom and visit with a physician) and diagnostic interval (time between first physician visit and histological diagnosis). Switzerland's healthcare system, Europe's costliest, lacks research on treating rare conditions, like mesenchymal tumors. This study examines the total interval of the diagnostic pathway for optimization strategies. Analyzing a dataset of 1028 patients presented from 2018 to 2021 to the Swiss Sarcoma Board (MDT/SB-SSN), this retrospective analysis delves into bone sarcoma (BS), soft-tissue sarcoma (STS), and their benign counterparts. Demographic and treatment data were extracted from medical records. The patient interval accounted for the largest proportion of the total interval and secondary care interval for the largest proportion of the diagnostic interval. Age, grade, and localization could be elicited as influencing factors of the length of different components of the total interval. An increasing age and tumor size, as well as the axial localization, could be elicited as factors increasing the probability of sarcoma. The patient and secondary care interval (SCI) offer the greatest potential for optimization, with SCI being the bottleneck of the diagnostic interval. New organizational structures for care work-ups are needed, such as integrated practice units (IPU) as integral part of value-based healthcare (VBHC).

Current stand on systemic therapy in localized soft tissue sarcomas: a clinician's perspective

Soft tissue sarcomas (STS) are rare heterogenous tumors derived from mesenchymal tissue. While surgery represents the primary treatment modality, the high recurrence rates following surgery alone necessitate consideration for systemic therapy in high-risk sarcomas. Despite multiple trials and meta-analyses over the last 3 decades, the role of chemotherapy remains controversial. It is crucial to accurately identify patients with high-risk diseases who may benefit the most from adjuvant and/or neoadjuvant chemotherapy. There is renewed interest in the potential to improve outcomes in localized resectable STSs with the addition of targeted and immunotherapeutic strategies. The review presented here is a summary of current evidence on systemic therapy in resectable localized STSs of the trunk and extremities to facilitate clinician decision-making.

The value of a specialized second-opinion pathological diagnosis for oral and maxillofacial lesions

OBJECTIVES

An error in the diagnosis of an oral or maxillofacial lesion could potentially be detrimental to a patient's prognosis and management. Major discrepancies between the initial and subsequent diagnoses of head and neck pathologies range from 7 to 53%. This study determined the rate of discrepancies found in the diagnoses of oral and maxillofacial lesions after a second opinion in Saudi Arabia.

METHODS

A retrospective single-center study was conducted by oral and maxillofacial pathology consultants to review all cases referred for a second opinion to the oral and maxillofacial pathology laboratory between January 2015 and December 2020. If the second-opinion diagnosis matched the original diagnosis, this was described as "agreement." If the second-opinion diagnosis did not match the original diagnosis but would not change the management or prognosis of a patient, this was classified as a "minor disagreement." If the second-opinion diagnosis resulted in the changing of a patient's management or prognosis, this was categorized as a "major disagreement." Chi-square test and Fisher's exact test were used to compare data between original and second-opinion diagnoses. A p-value of less than 0.05 was considered significant.

RESULTS

Of 138 cases, 59 (43%) had an initial diagnosis and a second-opinion diagnosis that were in major disagreement. The most common tumor for which there was a major disagreement was squamous cell carcinoma. No single factor influenced the occurrence of major disagreements.

CONCLUSIONS

Our evaluation reiterates the importance of obtaining a second opinion from a specialist in oral and maxillofacial pathology to improve the diagnostic accuracy for lesions. A formal system for this step, in addition to the obtaining of adequate clinical and radiographic information about a patient, is mandatory for the review of difficult cases.

Centralized and Interdisciplinary Therapy Management in the Treatment of Sarcomas

Sarcoma treatment requires a high level of expertise due to its rarity and heterogeneity. Sarcoma patients should, therefore, be referred to an expert centre as early as possible to ensure optimal treatment. Numerous studies have been carried out to provide evidence for this strategy. In compliance with the 2020 PRISMA guidelines, a systematic search was conducted in PubMed, EMBASE, Ovid Medline, ClinicalTrials.gov and Cochrane Library databases. The subject of these studies was the centralised treatment of adult sarcoma patients at expert centres and the use of interdisciplinary tumour boards. Uncertainty in therapy, delays in referral to expert centres, and limited access to therapeutic modalities continue to be a challenge in sarcoma therapy. At expert centres, diagnostic procedures were more frequently and adequately performed, and treatment was associated with an improvement in outcomes in the majority of studies: patients benefited from longer survival, lower local recurrence rates and a better postoperative outcome. The implementation of an interdisciplinary tumour board was associated with discrepant results. In a greater number of studies, it was associated with a lower local relapse rate, better overall survival and surgical outcome. In two studies, however, a shorter overall survival was observed. The establishment of expert centres and the consistent use of interdisciplinary tumour boards are important structures for ensuring multidisciplinary therapy approaches. There is growing evidence that this holds great potential for optimising sarcoma therapy.

The Efficacy of Molecular Analysis in the Diagnosis of Bone and Soft Tissue Sarcoma: A 15-Year Mono-Institutional Study

The histological diagnosis of sarcoma can be difficult as it sometimes requires the combination of morphological and immunophenotypic analyses with molecular tests. A total of 2705 tissue samples of sarcoma consecutively collected from 2006 until 2020 that had undergone molecular analysis were assessed to evaluate their diagnostic utility compared with histological assessments. A total of 3051 molecular analyses were performed, including 1484 gene fusions tested by c/qRT-PCR, 992 gene rearrangements analysed by FISH, 433 analyses of the gene status of MDM2, 126 mutational analyses and 16 NGS analysis. Of the samples analysed, 68% were from formalin-fixed, paraffin-embedded tissue and 32% were from frozen tissue. C/qRT-PCR and FISH analyses were conclusive on formalin-fixed, paraffin-embedded tissue in 74% and 76% of samples, respectively, but the combination of the two methods gave us conclusive results in 96% and 89% of frozen and formalin-fixed, paraffin-embedded tissues, respectively. We demonstrate the utility of c/qRT-PCR and FISH for sarcoma diagnosis and that each has advantages in specific contexts. We conclude that it is possible to accurately predict the sarcoma subtype using a panel of different subtype-specific FISH probes and c/qRT-PCR assays, thereby greatly facilitating the differential diagnosis of these tumours.

New benchmarks to design clinical trials with advanced or metastatic liposarcoma or synovial sarcoma patients: An EORTC - Soft Tissue and Bone Sarcoma Group (STBSG) meta-analysis based on a literature review for soft-tissue sarcomas

BACKGROUND

Recently, we performed a meta-analysis based on a literature review for STS trials (published 2003-2018, ≥10 adult patients) to update long-standing reference values for leiomyosarcomas. This work is extended for liposarcomas (LPS) and synovial sarcomas (SS).

MATERIALS AND METHODS

Study endpoints were progression-free survival rates (PFSRs) at 3 and 6 months. Trial-specific estimates were pooled per treatment line (first-line or pre-treated) with random effects meta-analyses. The choice of the therapeutic benefit to target in future trials was guided by the European Society for Medical Oncology Magnitude of Clinical Benefit Scale (ESMO-MCBS).

RESULTS

Information was acquired for 1030 LPS patients (25 trials; 7 first-line, 17 pre-treated, 1 both) and 348 SS patients (13 trials; 3 first-line, 10 pre-treated). For LPS, the overall pooled first-line PFSRs were 69% (95%-CI 60-77%) and 56% (95%-CI 45-67%) at 3 and 6 months, respectively. These rates were 49% (95%-CI 40-57%)/28% (95%-CI 22-34%) for >1 lines. For SS, first-line PFSRs were 74% (95%-CI 58-86%)/56% (95%-CI 31-78%) at 3 and 6 months, and pre-treated rates were 45% (95%-CI 34-57%)/25% (95%-CI 16-36%). Following ESMO-MCBS guidelines, the minimum values to target are 79% and 69% for first-line LPS (82% and 69% for SS) at 3 and 6 months. For pre-treated LPS, recommended PFSRs at 3 and 6 months suggesting drug activity are 63% and 44% (60% and 41% for SS).

CONCLUSIONS

New benchmarks are proposed for advanced/metastatic LPS or SS to design future histology-specific phase II trials. More data are needed to provide definitive thresholds for the different LPS subtypes.

Virtual Biopsy in Soft Tissue Sarcoma. How Close Are We?

A shift in radiology to a data-driven specialty has been unlocked by synergistic developments in imaging biomarkers (IB) and computational science. This is advancing the capability to deliver "virtual biopsies" within oncology. The ability to non-invasively probe tumour biology both spatially and temporally would fulfil the potential of imaging to inform management of complex tumours; improving diagnostic accuracy, providing new insights into inter- and intra-tumoral heterogeneity and individualised treatment planning and monitoring. Soft tissue sarcomas (STS) are rare tumours of mesenchymal origin with over 150 histological subtypes and notorious heterogeneity. The combination of inter- and intra-tumoural heterogeneity and the rarity of the disease remain major barriers to effective treatments. We provide an overview of the process of successful IB development, the key imaging and computational advancements in STS including quantitative magnetic resonance imaging, radiomics and artificial intelligence, and the studies to date that have explored the potential biological surrogates to imaging metrics. We discuss the promising future directions of IBs in STS and illustrate how the routine clinical implementation of a virtual biopsy has the potential to revolutionise the management of this group of complex cancers and improve clinical 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.

The 2020 WHO Classification of Soft Tissue Tumours: news and perspectives

Mesenchymal tumours represent one of the most challenging field of diagnostic pathology and refinement of classification schemes plays a key role in improving the quality of pathologic diagnosis and, as a consequence, of therapeutic options. The recent publication of the new WHO classification of Soft Tissue Tumours and Bone represents a major step toward improved standardization of diagnosis. Importantly, the 2020 WHO classification has been opened to expert clinicians that have further contributed to underline the key value of pathologic diagnosis as a rationale for proper treatment. Several relevant advances have been introduced. In the attempt to improve the prediction of clinical behaviour of solitary fibrous tumour, a risk assessment scheme has been implemented. NTRK-rearranged soft tissue tumours are now listed as an "emerging entity" also in consideration of the recent therapeutic developments in terms of NTRK inhibition. This decision has been source of a passionate debate regarding the definition of "tumour entity" as well as the consequences of a "pathology agnostic" approach to precision oncology. In consideration of their distinct clinicopathologic features, undifferentiated round cell sarcomas are now kept separate from Ewing sarcoma and subclassified, according to the underlying gene rearrangements, into three main subgroups (CIC, BCLR and not ETS fused sarcomas) Importantly, In order to avoid potential confusion, tumour entities such as gastrointestinal stroma tumours are addressed homogenously across the different WHO fascicles. Pathologic diagnosis represents the integration of morphologic, immunohistochemical and molecular characteristics and is a key element of clinical decision making. The WHO classification is as a key instrument to promote multidisciplinarity, stimulating pathologists, geneticists and clinicians to join efforts aimed to translate novel pathologic findings into more effective treatments.

Rare cancers in Japan: definition, clinical features and future perspectives

This review introduces the definition, epidemiology and therapeutic challenges of rare cancers and describes the establishment of the Rare Cancer Center at the National Cancer Center, Japan. Rare cancers are defined as malignant tumors with an incidence rate of less than 6 cases per 100 000 individuals. Due to their low incidence rate, medical treatment for rare cancers is more challenging than for more common cancer types. Specifically, 190 types of cancers, including bone and soft tissue sarcomas, gastrointestinal stromal tumors (GISTs), neuroendocrine tumors and gliomas, are classified as rare cancers. Individually, each of the rare cancers accounts for less than 1% of all cancers, but collectively they account for 15% of all cancers. On the basis of their medical management, rare cancers can be subclassified into two types: Type I (rare cancers within cancer-rare organs) and Type II (rare cancers within cancer-common organs). Most importantly, the outcomes for rare cancers are poorer compared to those of common cancers. In 2014, the Rare Cancer Center was established at the National Cancer Center to address the various challenges related to rare cancers. The Rare Cancer Center has adopted a multifaceted approach for overcoming these challenges, including active sharing of information through a dedicated website and an online seminar series 'Rare Cancer Meet the Expert', providing medical support through telephone consultations via a 'Rare Cancer Hotline', supporting basic research and establishing the 'MASTER KEY Project' aimed at developing new treatments.

Diagnostic Differences in Expert Second-Opinion Consultation Cases at a Tertiary Sarcoma Center

Soft tissue tumors are diagnostically challenging, and it is recommended that these are reported or reviewed by specialist soft tissue pathologists. We present our experience with second-opinion (consultation) cases in a specialist tertiary sarcoma center. The aim of this study was to determine areas of diagnostic difficulty in soft tissue pathology. We assessed 581 second-opinion cases which were reviewed by two experienced pathologists in a period of one year. There was 62% concordance between the original and the second-opinion diagnosis, with diagnostic discrepancy in 38%. The largest group of soft tissue neoplasms received for second opinion was fibroblastic/myofibroblastic tumors, and most major diagnostic problems were encountered in adipocytic and so-called “fibrohistiocytic” tumors. Major diagnostic errors impacting management were found in 148 cases (25%). Morphologic assessment of tumors, judicious use of molecular techniques, newer immunostains and their interpretation, along with importance of knowledge of rarer entities were found to be most useful in avoiding errors.

The Value of H3K27me3 Immunohistochemistry in Differentiating Malignant Peripheral Nerve Sheath Tumour with Its Histologic Mimickers

Background:

Diagnosis of malignant peripheral nerve sheath tumor (MPNST) is rather challenging due to its divergent morphologic heterogeneity and lack of specific ancillary test. The emergence of H3K27 trimethylation (H3K27me3) as a new immunohistochemistry (IHC) marker for MPNST have recently available to assist pathologists in differentiating MPNST from other histologic mimics. We aim to study the expression pattern of H3K27me3 in MPNST and its histologic mimickers and their association with the clinicopathological data.

Methodology:

A total of 59 benign and malignant spindle cell tumours (18 MPNST and 41 of its histologic mimickers which included 10 schwannoma, 13 neurofibroma, 4 synovial sarcoma, 3 fibrosarcoma, 2 gastrointestinal stromal tumour (GIST), 4 leiomyosarcoma, 1 spindle cell liposarcoma, 1 solitary fibrous tumour, 2 low grade fibromyxoid sarcoma and 1 unclassified spindle cell sarcoma), diagnosed from January 1998 to April 2018 in Hospital Universiti Sains Malaysia (HUSM) were tested for H3K27me3 by IHC. The MPNST histological grade was assessed based on the French Fe’de’ ration Nationale des Centres de LutteContre le Cancer (FNCLCC) for 3 tiers system (low grade, intermediate grade and high grade). The clinicopathological data were retrieved from the patients’ record.

Results:

A total of 61.1% (11/18 MPNST) showed loss of H3K27me3 expression which is statistically significant as compared to its histologic mimics (p<0.001). Similar findings (p=0.026) were also observed in high grade MPNST (81.8%), intermediate grade MPNST (100%) and 0% in low grade MPNST.

Conclusion:

H3K27me3, combined with other panel of markers, is useful in MPNST diagnosis to differentiate it from the histological mimickers.

Adherence to the guidelines and the pathological diagnosis of high-risk gastrointestinal stromal tumors in the real world

BACKGROUND

A multidisciplinary approach based on guidelines and pathological diagnosis by specialized pathologists are important for improving the prognosis and QoL of GIST patients. This study examined the adherence to the guidelines and the concordance of the pathological diagnosis of high-risk GISTs.

PATIENTS AND METHODS

Among 541 patients with high-risk GISTs recruited to the prospective registry between Dec. 2012 and Dec. 2015, 534 patients were analyzed after central pathology with KIT and DOG1 IHC and genotyping of KIT and PDGFRA.

RESULTS

Of the 534 patients, 432 (81%) received imatinib adjuvant therapy at a starting dose of 400 or 300 mg/day. Multivariate analysis indicated that age (HR 0.71; 95% CI 0.58-0.88), tumor size (HR for > 10 cm vs < 5 cm, 3.87; 95% CI 1.72-8.74), mitosis (HR for > 10 vs < 5, 3.54; 95% CI 1.84-6.79), tumor rupture (HR 3.69; 95% CI 1.43-9.52) and performance status (HR 0.55; 95% CI 0.31-0.99) were independently related to adjuvant therapy. Among the 534 high-risk GISTs diagnosed locally, 19 tumors (3.6%) were diagnosed as non-GISTs, and the other 93 (18.1%) GISTs were reclassified into lower risk categories by central pathology. Among 10 patients with non-GISTs and 8 patients with PDGFRA D842V mutations, 4 (40%) and 3 (38%) patients, respectively, continued the therapy after receiving the central pathology results.

CONCLUSIONS

The adherence to guidelines and the concordance of pathological diagnoses were comparatively good for high-risk GISTs. Central pathology may contribute to improved diagnosis, but further refinements may be required.

Management of localized extremity and retroperitoneal soft tissue sarcoma

The optimal management of localized soft tissue sarcomas of the extremities and retroperitoneum involves a high volume multidisciplinary team with expertise in sarcoma. In this review, we will highlight the importance of the sarcoma pathologist and imaging techniques prior to surgery and radiation. In addition, the data on neoadjuvant and adjuvant chemotherapy will be discussed. Finally, consideration is given to the importance of identifying genetic cancer predispositions, multidisciplinary management, long-term survivorship, and the current clinical trials for patients undergoing curative intent management.

Evidence-based data and rare cancers: The need for a new methodological approach in research and investigation

Rare cancers are not so rare, their incidence is increasing and, as a group, they have worse survival than the common cancers. These factors emphasise the societal need to ensure sufficient focus on research into their biological basis, aetiological factors, new more effective therapies and organisation of healthcare to improve access to best practice and innovation. Accuracy of diagnosis is one of the first hurdles to be overcome, with around one third of tumours being reclassified - by type or risk group - when subject to a centralised pathology review process. Timely access to appropriate expert knowledge is a second challenge for patients - in Europe this is being addressed by the establishment of European Reference Networks (ERNs) as part of the EU cross border healthcare initiative. There are ERNs for adult solid and haematological cancers and childhood cancers, all of which are individually rare. These ERNs will facilitate creation of large databases of rare tumours that will incorporate knowledge of their molecular features and build an evidence base for the effectiveness of innovative, biology-directed therapies. With an increasing focus on 'real world' outcome data, research methodologies are evolving, to include randomised registry trials and data linkage approaches that exploit the ever-richer information held on patients in routine health care data. The inclusion of genomic analysis into cancer diagnosis, treatment and risk prediction raises many issues for the conduct of clinical research and cohort studies and personal data sharing. Sophisticated means of pseudonymisation, together with full involvement of affected and 'at risk' patients, are supporting novel research designs and access to data that will continue to build the evidence base to improve outcomes for patients with rare cancers.

Pediatric cancer pathology review from a single institution: Neuropathology expert opinion is essential for accurate diagnosis of pediatric brain tumors

BACKGROUND AND OBJECTIVES

Second pathology review has been reported to improve accuracy in oncologic diagnoses, including pediatric malignancies. We assessed the impact of second review on the diagnosis of pediatric malignancies at a tertiary care referral center in Beirut, Lebanon.

METHODS

Pathology reports of patients treated at the Children's Cancer Institute in Lebanon were retrospectively reviewed for the period 2008-2016 and compared with same samples' diagnoses at St. Jude Children's Research Hospital. Diagnostic disagreements were divided into major, minor, and none based on their effect on diagnosis and/or patient management.

RESULTS

Second review was requested for 171 cases, accounting for 19% of all cases during that period. Second opinion was mostly requested for brain tumors (62% of all brain tumor cases) and neuroblastoma for NMYC testing (65% of all neuroblastoma), while hematologic malignancies had the fewest referrals (3% of all hematologic cases). Major disagreements in second review occurred in 20 cases (12% of total), and minor disagreements in 21 cases (12% of total). The largest proportion of major disagreements (71%) occurred in pediatric brain tumors, and novel molecular tests contributed to the diagnosis in 55% of these cases.

CONCLUSIONS

The availability of a specialized pediatric neuropathologist and a basic panel of relevant molecular testing are essential for appropriate diagnosis of pediatric brain tumors. Centers that do not have the available infrastructure in place can benefit greatly from second review referrals for this challenging subset of tumors.

Predictive and prognostic factors associated with soft tissue sarcoma response to chemotherapy: a subgroup analysis of the European Organisation for Research and Treatment of Cancer 62012 study

BACKGROUND

The European Organization for Research and Treatment of Cancer (EORTC) 62012 study was a Phase III trial of doxorubicin versus doxorubicin-ifosfamide chemotherapy in 455 patients with advanced soft tissue sarcoma (STS). Analysis of the main study showed that combination chemotherapy improved tumor response and progression-free survival, but differences in overall survival (OS) were not statistically significant. We analyzed factors prognostic for tumor response and OS, and assessed histological subgroup and tumor grade as predictive factors to identify patients more likely to benefit from combination chemotherapy.

METHODS

Central pathology review was performed by six reference pathologists. Gender, age, performance status, time from first presentation with sarcoma to starting palliative chemotherapy, tumor grade, histological subgroup, primary tumor site involvement, and sites of metastases were assessed as prognostic factors.

RESULTS

Three hundred and ten patients were included in this study. Discordance between local and central pathology opinion of tumor histology and tumor grade was observed in 98 (32%) and 122 (39%) cases, respectively. In multivariate analysis, liposarcoma patients had improved tumor response compared to other histological subgroups, whilst patients with metastases other than lung, liver or bone had a poorer response [odds ratio (OR) 0.42, 95% confidence interval (CI) 0.23-0.78; p = 0.006]. Patients with bone metastases had reduced OS [hazard ratio (HR) 1.56, 95% CI 1.16-2.09; p = 0.003]. By central pathology review, patients with undifferentiated pleomorphic sarcoma (UPS) had improved tumor response and OS with doxorubicin-ifosfamide compared to single-agent doxorubicin (OR 9.90, 95% CI 1.93-50.7 and HR 0.44, 95% CI 0.26-0.79, respectively). Grade III tumors had improved response with combination chemotherapy but there was no interaction between chemotherapy and grade on OS.

CONCLUSIONS

Prospective central pathology review of tumor histology should be integrated into future STS clinical trials. Doxorubicin-ifosfamide may be most appropriate for young, fit patients with poorly differentiated Grade III tumors including UPS.

Mesenchymal neoplasms of the head and neck: a cytopathologic analysis on fine needle aspiration

INTRODUCTION

Fine-needle aspiration (FNA) is commonly used to diagnose mass lesions discovered in the head and neck (H&N). Soft tissue neoplasms (STNs) are less common than epithelial tumors in this anatomic zone and often cause diagnostic difficulty when encountered in routine practice. In this study, we examine the frequency of H&N STNs at our institution and describe their cytomorphologic characteristics and clinical correlates.

METHODS

115 FNA specimens from 115 patients with STN of the H&N region were identified (2005-2015) from archives of The Johns Hopkins University Hospital. When available, slides from these cases were reviewed and any corresponding clinical and radiologic data was evaluated.

RESULTS

A total of 95 (83%) STNs were found to be primary to the H&N region and 20 (17%) were metastatic from distant sites. Of these 95 cases, 58 (61%) primary lesions were benign and 37 (39%) were malignant. The most common STNs were benign nerve sheath tumors, representing 40 (35%) cases: 30 schwannomas, 4 neurofibromas, and 6 were not further classified. The most aggressive neoplasms in terms of clinical outcome were leiomyosarcoma, Ewing sarcoma, synovial sarcoma, and chondrosarcoma. In 35 (60%) of the malignant cases and 25 (54%) of the benign cases a subsequent surgical resection was performed.

CONCLUSIONS

H&N can be involved by a wide range of primary and metastatic STNs. benign nerve sheath tumors are the most common STNs found on FNA in this region. Although not always definitively diagnostic, FNA of STNs can often provide a differential diagnosis that can help guide the need for an excision and/or further treatment.

Phase II study of MLN8237 (Alisertib) in advanced/metastatic sarcoma

BACKGROUND

Aurora kinase A (AURKA) is commonly overexpressed in sarcoma. The inhibition of AURKA by shRNA or by a specific AURKA inhibitor blocks in vitro proliferation of multiple sarcoma subtypes. MLN8237 (alisertib) is a novel oral adenosine triphosphate-competitive AURKA inhibitor.

PATIENTS AND METHODS

This Cancer Therapy Evaluation Program-sponsored phase II study of alisertib was conducted through the Alliance for Clinical Trials in Oncology (A091102). Patients were enrolled into histology-defined cohorts: (i) liposarcoma, (ii) leiomyosarcoma, (iii) undifferentiated sarcoma, (iv) malignant peripheral nerve sheath tumor, or (v) other. Treatment was alisertib 50 mg PO b.i.d. d1-d7 every 21 days. The primary end point was response rate; progression-free survival (PFS) was secondary. One response in the first 9 patients expanded enrollment in a cohort to 24 using a Simon two-stage design.

RESULTS

Seventy-two patients were enrolled at 24 sites [12 LPS, 10 LMS, 11 US, 10 malignant peripheral nerve sheath tumor (MPNST), 29 Other]. The median age was 55 years; 54% were male; 58%/38%/4% were ECOG PS 0/1/2. One PR expanded enrollment to the second stage in the other sarcoma cohort. The histology-specific cohorts ceased at the first stage. There were two confirmed PRs in the other cohort (both angiosarcoma) and one unconfirmed PR in dedifferentiated chondrosarcoma. Twelve-week PFS was 73% (LPS), 44% (LMS), 36% (US), 60% (MPNST), and 38% (Other). Grade 3-4 adverse events: oral mucositis (12%), anemia (14%), platelet count decreased (14%), leukopenia (22%), and neutropenia (42%).

CONCLUSIONS

Alisertib was well tolerated. Occasional responses, yet prolonged stable disease, were observed. Although failing to meet the primary RR end point, PFS was promising.

TRIAL REGISTRATION ID

NCT01653028.

Voluntary Second Opinions in Pediatric Bone and Soft Tissue Pathology: A Retrospective Review of 1601 Cases From a Single Mesenchymal Tumor Consultation Service

The diagnosis of bone and soft tissue tumors in children is challenging. These lesions are especially difficult for general pathologists. We reviewed our experience with pediatric mesenchymal tumors sent in consultation to our service, with the goal of identifying issues that most often prompted second-opinion referral. Roughly 16 000 cases were seen in toto, of which 1601 occurred in children. These included 491 bone cases and 1110 soft tissue cases. The cases were referred by private practices/nonacademic medical centers (85%), academic medical centers (8%), and pediatric hospitals (7%). Reasons for referral were (a) self-perceived lack of experience with pediatric mesenchymal tumors (n = 930), (b) second opinion requested by the clinician or patient (n = 132), and (c) perceived or real need for ancillary studies not available at the referring institution (n = 116). The referring pathologists suggested a diagnosis for 670 cases; of these, 476 (71%) were in essential agreement with our final diagnosis. Of the remaining, 139 (21%) were considered "minor disagreements" and 55 (8%) "major disagreements." The "major disagreement" cases could be divided into (a) malignant tumors submitted with benign diagnoses (58%), (b) benign tumors submitted with malignant diagnoses (25%), (c) nonneoplastic conditions submitted as representing neoplasms (11%), and (d) neoplasm submitted as representing nonneoplastic conditions (6%). Pediatric mesenchymal tumors comprised 10% of cases sent to our mesenchymal tumor consultation practice. The rates of diagnostic disagreement found in this study are roughly in accordance with prior studies of mandatory and voluntary second opinion in adult soft tissue tumors. Given the rarity of these tumors, expert second opinion may be of value.

Gross examination and reporting of soft tissue tumours: evaluation of compliance with the UK Royal College of Pathologists soft tissue sarcoma dataset

Aims

Soft tissue tumours are a heterogeneous group of neoplasms that can arise at almost every anatomical site. As they often show similar clinical and radiological findings, histology is the definitive diagnostic method and it is crucial that the surgical pathology report contains accurate, useful information for management and prognostication. The soft tissue sarcoma minimum dataset produced by the Royal College of Pathologists in the UK outlines a structure for handling and reporting soft tissue tumours, including the core data required, and aiding pathologists in forming a consistent reporting approach.

Methods

We assessed the information in surgical pathology reports for soft tissue lesions at a tertiary soft tissue centre, in 1 year prior to the development of this dataset, and 1 year after its release, to audit the comparative adequacy of macroscopic and microscopic information provided, and to assess for differences in reporting since the advent of routine ancillary molecular diagnostic testing.

Results and conclusions

We found that while essential information was always included in reports, more specific details contributing to better quality reports such as more detailed macroscopic descriptions and a higher proportion of clinical summaries with radiological correlation were included in 2011 than 2006, despite increasing workload. Specimen handling, particularly of core biopsies, was also improved, reflecting the increasing need to conserve the maximum amount of patient material for molecular investigations.

Ancillary molecular analysis in the diagnosis of soft tissue tumours: reassessment of its utility at a specialist centre

Aims

The histological diagnosis of soft tissue tumours (STTs) can be difficult, sometimes requiring a combination of morphology, immunophenotype and ancillary molecular tests. Many STTs are associated with characteristic genetic aberrations that can be assessed using fluorescence in situ hybridisation (FISH), reverse transcription-PCR (RT-PCR) or mutational analysis. We have previously assessed the practicality and sensitivity of using these modalities as part of the routine diagnosis of STT in paraffin-embedded material and now revisit the subject in light of further experience in this field.

Methods

200 consecutive cases from 2013 that had undergone FISH, RT-PCR or mutational analysis were assessed to evaluate their diagnostic utility compared with preliminary histological assessment.

Results

218 FISH, 91 RT-PCR and 43 mutational analysis tests were performed. Compared with the previous study, FISH for MDM2 amplification in possible well-differentiated/dedifferentiated liposarcomas, and mutational analysis for assessing KIT, PDGFR and BRAF mutations made up a large proportion of the workload (107 and 43 tests, respectively). As in the previous study, alveolar rhabdomyosarcoma showed the best FISH:RT-PCR concordance. Unlike previously, RT-PCR showed marginally higher sensitivity than FISH (78.9% and 76.9%), while continuing to demonstrate higher specificity (90.9% and 84.3%). RT-PCR again showed an increased failure rate (5.5%; 1% for FISH).

Conclusions

We demonstrate the continuing utility of RT-PCR and FISH for STT diagnosis, and that each has advantages in specific contexts. These ancillary molecular tests are important tools in both defining and excluding diagnoses of STT, which is crucial in determining prognosis and guiding appropriate management.

Evaluation of Molecular and Immunohistochemical Adjunct Modalities in the Diagnosis of Soft Tissue Neoplasms

The accurate diagnosis of soft tissue neoplasms has crucial therapeutic and prognostic importance. There is frequent morphologic overlap between entities, and ancillary modalities are used in the vast majority of diagnoses. Immunohistochemistry is rapid and inexpensive, and in addition to the older markers that mainly detected cytoplasmic proteins, antibodies can indirectly detect tumor-specific genetic and molecular abnormalities. The use of molecular diagnostic techniques is now widespread, with molecular services often integrated into routine histopathology laboratories; as their cost and turnaround times begin to parallel those for immunohistochemistry, we compared the usefulness of ancillary immunohistochemistry, molecular genetic, and molecular cytogenetic techniques in the diagnosis of soft tissue lesions. We evaluated the number and contribution of immunohistochemical tests and panels and of ancillary molecular techniques in the primary histopathologic diagnosis of 150 soft tissue lesions. Ninety of 150 cases required either only one immunohistochemical panel or minimal immunohistochemistry for diagnosis, while 39/150 required 2 to 4 panels. In 5/150, ancillary molecular tests alone (without immunohistochemistry) were diagnostically sufficient. The majority of cases required one immunohistochemical panel for diagnosis, with a smaller proportion requiring a second, and a minority requiring a third or fourth (which mainly comprised neoplasms for which the final diagnosis was uncertain). Certain neoplasms required both extensive immunohistochemistry and ancillary molecular testing, despite which the final diagnosis was inconclusive. Ancillary molecular techniques now make a significant contribution to soft tissue tumor diagnosis, being required in over one third (52/150) of cases, and were useful in confirming or excluding tumors that were not possible to conclusively diagnose with histology and immunohistochemistry. Only a small proportion of soft tissue neoplasms (16/150; all benign) did not require immunohistochemistry or ancillary molecular methods, with morphology alone being sufficient for diagnosis.

ALK Gene Translocation in Inflammatory Myofibroblastic Tumor of the Urinary Bladder: A Case Report

A 26-year-old woman with gross hematuria was seen in a previous hospital. Magnetic resonance imaging (MRI) showed a tumor at the dome of the urinary bladder with invasion outside of the bladder wall. The patient underwent transurethral resection of the bladder tumor (TUR-BT). From the result of the pathological examination, the tumor was suggested to be carcinosarcoma of the bladder. The patient was then referred to our hospital for treatment. We performed radical cystectomy and ileal conduit diversion. Pathological examination of the excised specimen revealed an inflammatory myofibroblastic tumor as the basis for immunostaining of anaplastic lymphoma kinase (ALK).

[Intra-abdominal soft tissue tumors. What needs to be known to reach the diagnosis with the help of immunohistochemistry, FISH and molecular biology]

Connective tissue tumors located inside the abdomen are a rare heterogeneous group of tumors, except for gastro-intestinal stromal tumors. They may be benign, malignant, or intermediate in terms of biologic potential. Pathologists have to remember the list of all the lesions possibly involved, with their immunohistochemical characteristics, and to know which molecular analyses are needed, with which expected results, and by which team they can be performed. The main tumor types are discussed with diagnostic tools and treatment consequences.

[Histopathological diagnostic concordance in bone and soft tissue sarcomas between two comprehensive cancer centers from eastern and western Europe: a collaborative experience]

INTRODUCTION

This study aims to assess the degree of concordance of histological diagnosis of bone and soft tissue sarcomas between a Comprehensive Cancer Center (CCC) of Eastern Europe - not specialized in this area of pathology - and an important CCC of Western Europe, which is one of the coordinators of a clinical reference network in sarcoma pathology. The goal is to have an overview of the sarcomatous pathology in a region of Eastern Europe and to discover diagnostic discrepancies between the two centers, while determining their cause.

MATERIALS AND METHODS

The initial diagnosis was compared with the revised diagnosis on 110 specimens from 88 patients with bone or soft tissue sarcomas from East-European CCC, in a one-year period of time.

RESULTS

Complete diagnostic agreement was observed in 55 cases (62.5%), a partial agreement in 23 cases (26.1%) and a major disagreement in 10 cases (11.4%). Major discrepancies of the histological type was observed in only 3 cases (3.4%): one case of discordance benign/malignant and 2 cases of discordance mesenchymal/non mesenchymal. Minor histological discrepancies - not affecting the management of the patient - were observed in 18 cases (20.4%). A major discordance in grading - potentially changing the management of the patient - was noted in 7 cases (7.9%), and a minor discrepancy in 5 cases (5.7%).

DISCUSSIONS

Some histological types were clearly overdiagnosed, like "adult fibrosarcomas" and "malignant peripheral nerve sheet tumors" (MPNST), mostly converted after the audit into "undifferentiated spindle cell sarcomas" or other types of sarcomas. Some "unclassified" sarcomas and "undifferentiated pleomorphic sarcomas" could be re-classified with the aid of an extensive panel of antibodies. Overall, immunohistochemistry was responsible, but not in exclusivity, for half of the minor discrepancies, and for 2 out of 3 cases of major histological discrepancies. Otherwise, the main cause of discrepancies was the difficulties in the interpretation of the morphology. Molecular biology was decisive in one case. Most grading discrepancies resulted from the appreciation of the mitotic index.

CONCLUSIONS

The profile of the sarcomatous pathology in the northwest region of Romania does not appear to differ significantly from other parts of Europe or the world, but a prospective epidemiological study would be necessary to confirm this assessment. The expansion of immunohistochemical antibody panel, the over-specialization of pathologists and, in the future, the establishment of a national network of referral centers in sarcoma pathology, are required for a high level of histological diagnosis in Eastern Europe. A periodic external audit, continuing this trans-European collaboration between the two centers, would be beneficial for monitoring progress.