Superior scapular location: An overlooked albeit frequent finding in elastofibroma dorsi

PURPOSE

To explore the frequency of superior scapular elastofibroma dorsi in a large patient series with elastofibroma dorsi.

METHODS

136 chest CTs from January 2016 to July 2022 reporting elastofibroma dorsi were retrospectively analyzed. Three radiologists assessed the number, size, and location of elastofibroma dorsi. Continuous variables underwent two-tailed t-tests with p < 0.05. Inter-observer agreement was assessed by using Cohen's Kappa values.

RESULTS

In 136 patients (mean age, 75.9 +/- 9.8 years; 117 female), 330 elastofibroma dorsi were found. Six (4.4 %) patients had single, 87 (64 %) double, 22 (16.2 %) triple and 21 (15.4 %) quadruple lesions. All single and double lesions were in the inferior scapular regions. 43 (31.6 %) patients had superior scapular lesions in addition to inferior scapular elastofibroma dorsi. Inferior scapular elastofibroma dorsi was significantly larger than superior scapular elastofibroma dorsi. The probability of a right superior lesion was significantly higher in patients with a larger right inferior lesion. Inter-observer agreement was very good for experienced radiologist (κ = 94.1) and good for other radiologists (κ = 79.4 and κ = 78).

CONCLUSION

In contrast to current belief, superior scapular elastofibroma dorsi accompanying the typical inferior scapular lesions is not uncommon and can even manifest bilaterally. To the best of our knowledge, this is the first case series reporting prevalence of quadruple elastofibroma dorsi.

How to develop new systemic treatments in ultra-rare cancers with high unmet needs? The case of alveolar soft-part sarcoma

Developing new drugs or generating evidence for existing drugs in new indications for ultra-rare cancers is complex and carries a high-risk of failure. This gets even harder in ultra-rare tumours, which have an annual incidence of 1 per 1,000,000 population or less. Here, we illustrate the problem of adequate evidence generation in ultra-rare tumours, using Alveolar Soft-Part Sarcomas (ASPS) - an ultra-rare sarcoma newly diagnosed in approximately 60 persons a year in the European Union - as an exemplar case showing challenges in development despite being potentially relevant for classes of agents. We discuss some possible approaches for addressing such challenges, especially focussing on constructive collaboration between academic groups, patients and advocates, drug manufacturers, and regulators to optimise drug development in ultra-rare cancers. This article, written by various European stakeholders, proposes a way forward to ultimately get better options for patients with ultra-rare cancers.

Establishment and characterization of NCC-ASPS2-C1: a novel patient-derived cell line of alveolar soft part sarcoma

Alveolar soft part sarcoma (ASPS) is a rare mesenchymal tumor characterized by rearrangement of the ASPSCR1 and TFE3 genes and a histologically distinctive pseudoalveolar pattern. ASPS progresses slowly, but is prone to late metastasis. As ASPS is refractory to conventional chemotherapy, the only curative treatment is complete surgical resection. The prognosis of advanced and metastatic cases is poor, highlighting the need for preclinical research to develop appropriate treatment options. However, ASPS is extremely rare, accounting for < 1% of all soft tissue sarcomas, and only one patient-derived ASPS cell line is available from public cell banks worldwide for research. This study reports the establishment of a novel ASPS cell line derived from the primary tumor tissue of an ASPS patient, named NCC-ASPS2-C1. This cell line retains the ASPSCR1-TFE3 fusion gene, which is characteristic of ASPS. The characterization of this cell line revealed stable growth, spheroid formation, and invasive properties. By screening a drug library using NCC-ASPS2-C1, we identified several drugs that inhibited the proliferation of ASPS cells. In conclusion, the establishment of NCC-ASPS2-C1 provides a valuable resource for advancing ASPS research and developing novel treatments for this challenging disease.

The role of 18F-FDG PET in minimizing variability in gross tumor volume delineation of soft tissue sarcomas

BACKGROUND

Accurate gross tumor volume (GTV) delineation is a critical step in radiation therapy treatment planning. However, it is reader dependent and thus susceptible to intra- and inter-reader variability. GTV delineation of soft tissue sarcoma (STS) often relies on CT and MR images.

PURPOSE

This study investigates the potential role of 18F-FDG PET in reducing intra- and inter-reader variability thereby improving reproducibility of GTV delineation in STS, without incurring additional costs or radiation exposure.

MATERIALS AND METHODS

Three readers performed independent GTV delineation of 61 patients with STS using first CT and MR followed by CT, MR, and 18F-FDG PET images. Each reader performed a total of six delineation trials, three trials per imaging modality group. Dice Similarity Coefficient (DSC) score and Hausdorff distance (HD) were used to assess both intra- and inter-reader variability using generated simultaneous truth and performance level estimation (STAPLE) GTVs as ground truth. Statistical analysis was performed using a Wilcoxon signed-ranked test.

RESULTS

There was a statistically significant decrease in both intra- and inter-reader variability in GTV delineation using CT, MR 18F-FDG PET images vs. CT and MR images. This was translated by an increase in the DSC score and a decrease in the HD for GTVs drawn from CT, MR and 18F-FDG PET images vs. GTVs drawn from CT and MR for all readers and across all three trials.

CONCLUSION

Incorporation of 18F-FDG PET into CT and MR images decreased intra- and inter-reader variability and subsequently increased reproducibility of GTV delineation in STS.

[Congenital spindle cell/sclerosing rhabdomyosarcoma: a clinicopathological analysis]

Objective: To investigate the clinicopathological features, immunophenotype and molecular genetic characteristics of congenital spindle cell/sclerosing rhabdomyosarcoma. Methods: Sixteen cases (including 10 consultation cases) of congenital spindle cell/sclerosing rhabdomyosarcoma diagnosed at the Beijing Children's Hospital, Capital Medical University, Beijing China, from April 2017 to January 2022 were collected. These cases were evaluated for clinical profiles, histomorphological features, immunophenotype and molecular characteristics. Results: Among the 16 patients, 9 were male and 7 were female. Five cases were present during maternal pregnancy and 11 cases were found immediately after birth. The tumors were located in the chest wall, low back, retroperitoneum, extremities or perineum. The tumors consisted of fasciculated spindle-shaped cells with localized mesenchymal sclerosis and vitreous metaplasia. Immunohistochemistry showed that the tumor cells expressed Desmin, Myogenin, MyoD1, SMA, CD56 and ALK to varying degrees, but not other markers such as CD34, CD99, pan-TRK, S-100 and BCOR. FISH analyses with NCOA2 (8q13) and VGLL2 (6q22) gene breakage probes revealed a breakage translocation in chromosome NCOA2 (8q13) in 4 cases (4/11). In the 6 cases subject to sequencing, a mutation at the p.L122R locus of MYOD1 gene was detected in 1 case (1/6). Two cases were examined by electron microscopy, which showed bundle-arranged myofilaments with some primitive myofilament formation. Five cases were resected with simple surgery, 2 cases were biopsied and followed up with observation only, and 9 cases were treated with surgery and adjuvant chemotherapy. Follow-up was available in 12 cases. At the end of the follow-up, 2 of the 12 patients developed local recurrences and 2 patients survived with disease. Conclusions: Congenital spindle cell/sclerosing rhabdomyosarcoma is a rare subtype of congenital rhabdomyosarcoma. It more commonly occurs in the chest, back and lower limbs of infants than other sites. NCOA2/VGLL2 gene fusion seems to be the most common genetic change. Its prognosis is better than other subtypes of rhabdomyosarcoma and those in adolescents and adults with the same subtype. Analysis and summary of its clinicopathological features can help differentiate it from other soft tissue tumors in infants and children and provide the information for appropriate treatments.

Prognostic factors and treatment outcomes in patients with pleomorphic rhabdomyosarcoma: a population-based cohort study

BACKGROUND

Pleomorphic rhabdomyosarcoma is a rare sarcoma in adults. The clinical characteristics, outcomes and prognostic factors associated with pleomorphic rhabdomyosarcoma remain unclear.

METHODS

We retrospectively analyzed data from the Bone and Soft Tissue Tumor Registry of Japan, and enrolled patients with pleomorphic rhabdomyosarcoma. Disease-specific overall survival, local recurrence-free survival and distant metastasis-free survival were estimated using the Kaplan-Meier method; Cox regression model was used to identify prognostic factors.

RESULTS

In total, 182 patients with pleomorphic rhabdomyosarcoma were included. Median age was 63 (range 20-95) years. The lower extremity (48%) was the most frequent tumor origin site, while head and neck were rare (4%). A total of 43 patients (24%) had distant or regional nodal metastases at first presentation. In all cases, the 2-year and 5-year survival rates were 66.3% and 54.1%, respectively. Distant metastasis was a significant poor prognostic factor (Hazard ratio 6.65; 95% confidence intervals, 3.00-14.75, P < 0.0001), with median survival of such patients being 9.4 (95% confidence intervals: 5.3-12.2) months. In 134 localized cases, the 2-year and 5-year survival rates were 91.5% and 68.3%, respectively. Large tumor size and older age were associated with poorer prognosis. Through data from localized and locally curative cases extracted and adjusted by propensity score matching, we found that perioperative chemotherapy did not improve disease-specific overall survival, distant metastasis-free survival or local recurrence-free survival.

CONCLUSIONS

Clinical characteristics and outcomes of pleomorphic rhabdomyosarcoma are similar to those of other high-grade soft tissue sarcomas. Pleomorphic rhabdomyosarcoma may be less chemosensitive, and a strategy other than the standard cytotoxic chemotherapy is required to improve its prognosis.

Localized Myxofibrosarcoma: A Retrospective Analysis of Primary Therapy and Prognostic Factors in 134 Patients in a Single Institution

BACKGROUND

Primary therapy of localized myxofibrosarcoma (MFS) remains controversial. Primary resection is complicated by a high rate of local recurrence, and the refractoriness to non-surgical treatment results in a higher risk of metastasis. The aim of the present study was to contribute the findings of a single sarcoma-specialized center and encourage investigating new treatment options.

PATIENTS AND METHODS

We analyzed 134 patients treated with localized MFS in our center regarding prognostic factors defining overall survival, local recurrence, and metastasis. We focused on multimodal treatment of localized MFS: surgery, radiation, chemotherapy, hyperthermia, and isolated limb perfusion.

RESULTS

The 5-year OS was 74.9%. From a total of 134 patients: 74 (55.2%) stayed disease free, 48 (35.8%) had a local recurrence (LR), and 23 (17.2%) developed a distant metastasis (DM). The 5-year LR-free survival (LRFS) and DM-free survival (DMFS) were 66.1% and 80.8%, respectively. Older age, tumor size (cT) cT ≥ 2, non-extremity localization, and distant metastasis were adverse predictive factors for OS. Performing an incision biopsy, surgery in a sarcoma-center, wide local excision or compartment-oriented excision, negative margins, and radiotherapy were positive predictive factors for LR. Tumor size cT ≥ 3 was a negative predictive factor for DM. Grading was a negative predictive factor for LR (G ≥ 2) and for DM (G3) in the multivariable analysis.

CONCLUSION

Adjuvant radiation had a positive impact on LRFS in all localized tumor stages, even in cT1 tumors. Chemotherapy did not have a significant impact on DMFS, regardless of tumor stage. Our findings indicate that myxofibrosarcoma may be a chemotherapy-resistant entity and a much closer monitoring is required, in case of neoadjuvant treatment.

Oncovascular Surgery for Soft-Tissue Sarcomas of the Lower Limbs with Vascular Contact: Comparison of Arterial Reconstruction and Arterial Subadventitial Dissection

BACKGROUND

Soft-tissue sarcomas represent approximately 1% of adult malignancies. When they involve the lower limbs (LLs) and come into contact with blood vessels, the therapeutic choice was historically a primary amputation. Today, radical surgical resection with wide margins of safety is the primary therapeutic option for multidisciplinary limb-salvage surgery. The aim was to compare the morbidity and mortality results of an oncologic resection of LL soft-tissue sarcomas with arterial replacement (AR) to that obtained with arterial subadventitial dissection (ASD).

METHODS

All consecutive patients with arterial close contact soft-tissue sarcomas of LL were included. Two groups were formed: an AR group where AR was performed following surgical resection and an ASD group in which the artery in contact with the tumor was preserved by ASD. Fisher's exact test was used.

RESULTS

Eighteen patients with a median age of 61.50 (interquartile range [IQR] 54.25-69.75) years underwent oncovascular surgery with orthopedic and vascular surgeons between August 2013 and May 2022. Sarcomas were all located in the thigh. Nine patients were enrolled in each of the 2 groups. The 6-month survival rate was 77.78% in the AR group and 100% in the ASD group (P = 0.4). In the AR group, 2 patients presented local recurrence, with a median recurrence-free time of 24.48 (IQR 14.08-34.87) months, and 2 patients presented distant metastases, with metastasis-free time of 13.45 (IQR 8.12-35.11) months. In the ASD group, no local recurrence was observed, and 2 patients presented metastases with a median metastasis-free time of 3.90 (IQR 3.18-4.61) months. Six patients in the AR group and 7 in the ASD group required surgical revision (P = 0.017). No major amputation was necessary.

CONCLUSIONS

Oncovascular surgery for LL sarcomas with ASD is certainly more locally morbid perioperatively than that with AR but provides patients with better medium-term survival.

Treatment and Diagnose of Spinal Phosphaturic Mesenchymal Tumor: A Case Report and a Systematic Literature Review

BACKGROUND

Spinal phosphaturic mesenchymal tumor (PMT) is a rare disorder but can be cured once the diagnosis is clear and a complete removal by surgery is performed. To the best of our knowledge, only 22 cases in the spine have been described, and we report a case with the largest number of spinal segments (T12-L5) affected among spine PMT cases.

METHODS

A comprehensive literature search was performed until May 23, 2023, following the Preferred Reporting Items for Systematic Reviews guidelines. Studies were chosen through relevant PubMed, Web of Science, and EMBASE searches to prioritize obtaining the largest studies. The Medical Subject Headings and Boolean operators employed for this search were ("PMT" or "TIO" or "Tumor-induced osteomalacia" or "phosphaturic mesenchymal tumor") and ("spine" or "spinal"). Two researchers (L.S.Z. and D.B.C) independently reviewed and evaluated the included articles. Any differing opinions were discussed until a consensus was reached. A total of 18 studies were included. A case report is also presented.

RESULTS

We report a case of spinal PMT. The full text of the relevant articles was construed. A total of 18 studies were reviewed and consolidated. These articles are roughly divided into the following 5 subcategories: 1) clinical features and baseline distribution, 2) laboratory and imaging findings, 3) pathological manifestations, and 4) surgical methods and treatment options.

CONCLUSIONS

Spinal PMT is very rare with a high rate of misdiagnosis and debilitating complications, so it is of significance to increase awareness of the disease among spine surgeons consulted by patients with spinal PMT. 68Ga-DOTATOC-PET/CT shows very high sensitivity to the spinal PMT but there is no way to exactly determine the location of the tumor. PMT has unique immunohistochemical characteristics and malignant PMT is rare. Once diagnosed, complete surgical excision is the recommended treatment. Burosumab is one of the available options, especially in cases that are recurrent and difficult to surgically resect.

Clinicopathological Profile and Survival Outcomes in Patients with Localised Extremity Synovial Sarcomas

AIMS

Synovial sarcoma is a rare but aggressive variant of soft-tissue sarcoma. Literature is sparse and reported mostly from the West. We analysed the clinical profiles and prognostic factors of extremity synovial sarcoma patients in order to study their clinical journey.

MATERIALS AND METHODS

This was a retrospective analysis. All patients with extremity synovial sarcoma treated between 1992 and 2020 were included. Patients with metastases at presentation were excluded. A descriptive analysis of demographic and clinicopathological features of patients undergoing limb salvage surgery (LSS) or amputation was carried out. Overall survival and disease-free survival were calculated for the entire cohort as well as for the LSS and amputation groups. Factors prognostic for survival were identified.

RESULTS

In total, 157 patients had localised extremity synovial sarcoma. Predominantly, young adults (median 31 years) and males (61%) were affected. Over 70% of patients presented after recurrence or unplanned surgeries. Sixty-seven per cent of tumours were >5 cm, 69% were deep and 23% involved bone. The limb salvage rate was 64%. In the LSS group, adjuvant radiotherapy and chemotherapy were given to 72% and 68% of patients, respectively. In the amputation group, 72% of patients received adjuvant chemotherapy. In a median follow-up of 59 months, 39.4% of patients had recurrences, the majority (61.2%) were systemic. Five-year overall survival and disease-free survival were 53.4% and 49.8%, respectively. Overall survival was 63.9% and 29.7% in the LSS and amputation groups, respectively. On multivariate analysis, tumour size, depth, omission of radiotherapy and bone invasion were found to be the adverse prognostic factors.

CONCLUSION

This is one of the largest studies on extremity synovial sarcoma. Mostly males and young adults were affected. The limb salvage rate was 64%, despite most being referred after unplanned surgery. Almost 70% of patients received radiotherapy and chemotherapy. Overall survival was inferior in the amputation group. Tumour size >5 cm, depth and bone invasion were negative, whereas adjuvant radiotherapy was a positive prognostic factor for survival. Chemotherapy had no impact on survival.

Atypical Spindle Cell/Pleomorphic Lipomatous Tumor With Sarcomatous Transformation: Clinicopathologic and Molecular Analysis of 4 Cases

Atypical spindle cell/pleomorphic lipomatous tumor (ASPLT) is a recently described adipocytic tumor predominantly affecting the subcutaneous soft tissues of adults. Previous studies have shown that ASPLT follows a benign clinical course with a 4% to 12% local recurrence rate and no risk of dedifferentiation. Herein, we describe the clinicopathologic and molecular findings of 4 cases of ASPLT showing unequivocal sarcomatous transformation. Three patients were male and one was female, aged 65, 70, 74, and 78 years. Two cases presented as mass-forming lesions, while 1 case was incidentally discovered. The tumors measured 30, 55, 80, and 110 mm and occurred in the chest wall (n = 2) or arm (n = 2); all were subcutaneous. Microscopically, they showed a biphasic appearance comprising a low-grade ASPLT component and a high-grade sarcomatous component. The low-grade components showed features in the spectrum of either atypical pleomorphic lipomatous tumor (n = 2) or atypical spindle cell lipomatous tumor (n = 2). The high-grade components displayed leiomyosarcoma-like (n = 2), pleomorphic liposarcoma-like (n = 1) or undifferentiated sarcoma-like (n = 1) morphology. On immunohistochemistry, tumors were negative for MDM2 and showed loss of RB1 expression. In addition, the leiomyosarcoma-like areas seen in 2 cases were positive for smooth muscle actin and H-caldesmon. Single-nucleotide polymorphism array, performed in 3 cases, showed deletions of TP53, RB1, and flanking genes in both components. In contrast, the sarcomatous components showed more complex genomic profiles with rare segmental gains and recurrent loss of PTEN (n = 3), ATM (n = 2), and CDKN2A/B (n = 2) among other genes. Whole exome sequencing identified a TP53 variant in one case and an ATRX variant in another, each occurring in both tumor components. Limited clinical follow-up showed no recurrence or metastasis after 1 to 13 months (median, 7.5 months) postsurgical excision. Altogether, our data support that ASPLT can rarely develop sarcomatous transformation and offer insights into the molecular mechanisms underlying this event.

CT and MR imaging findings of head and neck chondrosarcoma

OBJECTIVES

This study investigated the imaging features of head and neck chondrosarcoma (HNCS) according to its origin and pathologic subtype.

METHODS

Patients who were pathologically diagnosed with HNCS between January 2000 and April 2022 were retrospectively reviewed. Lesions were classified based on their origin and pathologic subtype. The size and margin were evaluated on the image. Internal calcification and the effects on adjacent bone were assessed using computed tomography (CT) images, while signal intensity and contrast enhancement patterns were analyzed using magnetic resonance (MR) imaging.

RESULTS

Thirteen HNCSs were included in this study: 8 bone tumors (61.5%) and 5 soft tissue tumors (38.5%). The bone tumors were pathologically diagnosed as conventional (n = 5) and mesenchymal type (n = 3). Soft tissue tumors were defined as myxoid type. The main symptoms were swelling (90.9%) and pain (72.7%). The lesions measured 4.5 cm on average. The margins showed benign and well-defined except for the mesenchymal type. On CT, most bone tumors (75%) showed internal calcification with remodeling or destruction of the adjacent bone. No soft tissue tumors, except one case, showed internal calcification or destruction of the adjacent bone. MR imaging features were non-specific (T2 high signal intensity and contrast enhancement).

CONCLUSIONS

HCNS showed various imaging findings according to their origin and pathologic subtype. HNCS should be differentiated if a bone tumor shows internal calcification and affects the adjacent bone. When diagnosing slow-growing soft tissue tumors, even if low possibility, HNCS should be considered.

Differentiation of benign and metastatic lymph nodes in soft tissue sarcoma

Lymph node metastasis (LNM) occurs in less than 5% of soft tissue sarcoma (STS) patients and indicates an aggressive course of disease. Suspicious lymph nodes (LN) in staging imaging are a frequent topic of discussion in multidisciplinary tumor boards. Predictive markers are needed to facilitate stratification and improve treatment of STS patients. In this study, 56 STS patients with radiologically suspicious and subsequently histologically examined LN were reviewed. Patients with benign (n = 26) and metastatic (n = 30) LN were analyzed with regard to clinical, laboratory and imaging parameters. Patients with LNM exhibited significantly larger short axis diameter (SAD) and long axis diameter (LAD) vs. patients with benign LN (median 22.5 vs. 14 mm, p < 0.001 and median 29.5 vs. 21 mm, p = 0.003, respectively). Furthermore, the presence of central necrosis and high maximal standardized uptake value (SUVmax) in FDG-PET-CT scans were significantly associated with LNM (60 vs. 11.5% of patients, p < 0.001 and median 8.59 vs. 3.96, p = 0.013, respectively). With systemic therapy, a slight median size regression over time was observed in both metastatic and benign LN. Serum LDH and CRP levels were significantly higher in patients with LNM (median 247 vs. 187.5U/L, p = 0.005 and 1.5 vs. 0.55 mg/dL, p = 0.039, respectively). This study shows significant associations between LNM and imaging features as well as laboratory parameters of STS patients. The largest SAD, SUVmax in FDG-PET-CT scan, the presence of central necrosis, and high serum LDH level are the most important parameters to distinguish benign from metastatic LNs.

Spontaneous expression of the CIC::DUX4 fusion oncoprotein from a conditional allele potently drives sarcoma formation in genetically engineered mice

CIC::DUX4 sarcoma (CDS) is a rare but highly aggressive undifferentiated small round cell sarcoma driven by a fusion between the tumor suppressor Capicua (CIC) and DUX4. Currently, there are no effective treatments and efforts to identify and translate better therapies are limited by the scarcity of patient tumor samples and cell lines. To address this limitation, we generated three genetically engineered mouse models of CDS (Ch7CDS, Ai9CDS, and TOPCDS). Remarkably, chimeric mice from all three conditional models developed spontaneous soft tissue tumors and disseminated disease in the absence of Cre-recombinase. The penetrance of spontaneous (Cre-independent) tumor formation was complete irrespective of bi-allelic Cic function and the distance between adjacent loxP sites. Characterization of soft tissue and presumed metastatic tumors showed that they consistently expressed the CIC::DUX4 fusion protein and many downstream markers of the disease credentialing the models as CDS. In addition, tumor-derived cell lines were generated and ChIP-seq was preformed to map fusion-gene specific binding using an N-terminal HA epitope tag. These datasets, along with paired H3K27ac ChIP-sequencing maps, validate CIC::DUX4 as a neomorphic transcriptional activator. Moreover, they are consistent with a model where ETS family transcription factors are cooperative and redundant drivers of the core regulatory circuitry in CDS.

Prostatic stromal tumour of uncertain malignant potential in a dog

An 11-year-old male Miniature Dachshund dog was presented with dyschezia. Computed tomography examination 35 days after the initial visit revealed a prostate mass (4.0 × 3.5 × 2.7 cm) and prostatectomy and orchiectomy were performed 13 days later. Grossly, the prostate was rubbery and the cut surface of the mass was swollen. The mass was whitish and demarcated from the surrounding tissues. Microscopically, the mass had a capsulate consisting of atypical spindloid stromal cells arranged in a phyllode pattern and also in a fasciculated pattern admixed with acinar ductal cells. Atypical stromal cells contained round-to-oval finely hyperchromatic nuclei that had distinct nuclei and abundant eosinophilic cytoplasm. Immunohistochemically, the atypical stromal cells were positive for vimentin, CD34, desmin, α-smooth muscle actin, progesterone receptor and androgen receptor but negative for cytokeratin AE1/AE3, p63, c-Kit, DOG-1 and SOX10. On the basis of these findings, the tumour was diagnosed as a prostatic stromal tumour of uncertain malignant potential.

Local treatment in initially unresected non-rhabdomyosarcoma soft-tissue sarcomas of children and adolescents: A retrospective single-center experience

BACKGROUND

Pediatric non-rhabdomyosarcoma soft-tissue sarcomas (NRSTS) are a heterogeneous group of aggressive tumors. Patients with locally advanced/initially unresected disease represent a subset of patients with unsatisfactory outcome: limited data are available on the best treatment approach, in particular regarding local therapy.

METHODS

This retrospective analysis concerned 71 patients < 21 years old with nonmetastatic, initially unresected adult-type NRSTS, treated at a referral center for pediatric sarcomas from 1990 to 2021. Patients were treated using a multimodal approach, based on the protocols adopted at the time of their diagnosis.

RESULTS

The series included a selected group of patients with unfavorable clinical characteristics, i.e., most cases had high-grade and large tumors, arising from axial sites in 61% of cases. All patients received neoadjuvant chemotherapy, 58 (82%) had delayed surgery (R0 in 45 cases), and 50 (70%) had radiotherapy. Partial response to chemotherapy was observed in 46% of cases. With a median follow-up of 152 months (range, 18-233), 5-year event-free survival (EFS) and overall survival (OS) were 39.9% and 56.5%, respectively. Survival was significantly better for patients who responded to chemotherapy, and those who had a delayed R0 resection. Local relapse at 5 years was 7.7% for patients who did not undergo delayed surgery.

CONCLUSIONS

Our series underscores the unsatisfactory outcome of initially unresected NRSTS patients. Improving the outcome of this patient category requires therapeutic strategies able to combine novel effective systemic therapies with a better-defined local treatment approach to offer patients the best chances to have R0 surgery.

Improved nationwide survival of sarcoma patients with a network of reference centers

BACKGROUND

We investigated the impact of the implementation of a network of reference centers for sarcomas (NETSARC) on the care and survival of sarcoma patients in France since 2010.

PATIENTS AND METHODS

NETSARC (netsarc.org) is a network of 26 reference sarcoma centers with specialized multidisciplinary tumor boards (MDTBs), funded by the French National Cancer Institute (INCa) since 2010. Its aims are to improve the quality of diagnosis and care of sarcoma patients. Patients' characteristics, treatments, and outcomes are collected in a nationwide database. The objective of this analysis was to compare the survival of patients in three periods: 2010-2012 (non-exhaustive), 2013-2015, and 2016-2020.

RESULTS

A total of 43 975 patients with sarcomas, gastrointestinal stromal tumors (GISTs), or connective tissue tumors of intermediate malignancy were included in the NETSARC+ database since 2010 (n = 9266 before 2013, n = 12 274 between 2013 and 2015, n = 22 435 in 2016-2020). Median age was 56 years, 50.5% were women, and 13.2% had metastasis at diagnosis. Overall survival was significantly superior in the period 2016-2020 versus 2013-2015 versus 2010-2012 for the entire population, for patients >18 years of age, and for both metastatic and non-metastatic patients in univariate and multivariate analyses (P < 0.0001). Over the three periods, we observed a significantly improved compliance to clinical practice guidelines (CPGs) nationwide: the proportion of patients biopsied before surgery increased from 62.9% to 72.6%; the percentage of patients presented to NETSARC MDTBs before first surgery increased from 31.7% to 44.4% (P < 0.0001). The proportion of patients with R0 resection on first surgery increased (from 36.1% to 46.6%), while R2 resection rate decreased (from 10.9% to 7.9%), with a better compliance and improvement in NETSARC centers.

CONCLUSIONS

The implementation of the national reference network for sarcoma was associated with an improvement of overall survival and compliance to guidelines nationwide in sarcoma patients. Referral to expert networks for sarcoma patients should be encouraged, though a better compliance to CPGs can still be achieved.

Case Series of Soft Tissue Sarcoma Patients with Brain Metastasis with Implications from Genomic and Transcriptomic Analysis

PURPOSE

Brain metastasis rarely occurs in soft tissue sarcoma (STS). Here, we present five cases of STS with brain metastases with genetic profiles.

MATERIALS AND METHODS

We included five patients from Seoul National University Hospital who were diagnosed with STS with metastasis to the brain. Tissue from the brain metastasis along with that from the primary site or other metastases were used for DNA and RNA sequencing to identify genetic profiles. Gene expression profiles were compared with sarcoma samples from The Cancer Genome Atlas.

RESULTS

The overall survival after diagnosis of brain metastasis ranged from 2.2 to 34.3 months. Comparison of mutational profiles between brain metastases and matched primary or other metastatic samples showed similar profiles. In two patients, copy number variation profiles between brain metastasis and other tumors showed several differences including MYCL, JUN, MYC, and DDR2 amplification. Gene ontology analysis showed that the group of genes significantly highly expressed in the brain metastasis samples was enriched in the G-protein coupled receptor activity, structural constituent of chromatin, protein heterodimerization activity, and binding of DNA, RNA, and protein. Gene set enrichment analysis showed enrichment in the pathway of neuroactive ligand-receptor interaction and systemic lupus erythematosus.

CONCLUSION

The five patients had variable ranges of clinical courses and outcomes. Genomic and transcriptomic analysis of STS with brain metastasis implicates possible involvement of complex expression modification and epigenetic changes rather than the addition of single driver gene alteration.

Psammomatoid ossifying fibroma in the frontal sinus: An intriguing clinical encounter-A detailed case report

BACKGROUND

Psammomatoid ossifying fibroma (POF) is a rare craniofacial neoplasm, primarily affecting the maxillofacial region, and typically observed in adolescents and young adults. This case report presents a unique occurrence of POF in a 50-year-old male, defying the conventional age range and exhibiting an unusual anatomical location within the frontal sinus.

CASE

A 50-year-old male with a prior history of cecal adenocarcinoma and colectomy presented with left eye proptosis and new-onset headaches. Imaging revealed a well-defined calcified mass in the left frontal sinus, leading to a diagnosis of POF. Open surgical resection was performed to remove the tumor, and histopathological evaluation confirmed its diagnosis as psammomatoid ossifying fibroma. The patient exhibited no postoperative complications or signs of recurrence.

CONCLUSION

This case underscores the diverse clinical presentations and diagnostic challenges associated with POF, emphasizing the importance of accurate diagnosis and multidisciplinary collaboration. Further research is needed to explore the genetic underpinnings and optimal management strategies for this intriguing condition.

Extremity and Truncal Soft Tissue Sarcoma: Risk Assessment and Multidisciplinary Management

Extremity and truncal soft tissue sarcomas are a heterogeneous group of rare cancers that arise from mesenchymal tissues. Hence, the adoption of tailored risk assessment and prognostication tools plays a crucial role in optimizing the decision-making for which of the many possible treatment strategies to select. Management of these tumors requires a multidisciplinary strategy, which has seen significant development in recent decades. Surgery has emerged as the primary treatment approach, with the main goal of achieving microscopic negative tumor margins. To reduce the likelihood of local recurrence, loco-regional treatments such as radiation therapy and isolated limb perfusion are often added to the treatment regimen in combination with surgery. This approach also enables surgeons to perform limb-sparing surgery, particularly in cases where a positive tumor margin is expected. Chemotherapy may also provide a further benefit in decreasing the probability of local recurrence or reducing distant metastasis in selected patients. Selecting the optimal treatment strategy for these rare tumors is best accomplished by an experienced multi-disciplinary team.

A comprehensive analysis of CD47 expression in various histological subtypes of soft tissue sarcoma: exploring novel opportunities for macrophage-directed treatments

PURPOSE

The CD47 molecule, often referred to as the "do not eat me" signal, is frequently overexpressed in tumor cells. This signaling pathway limits phagocytosis by macrophages. Our objective was to determine CD47 abundance in various soft tissue sarcomas (STS) to investigate whether it could serve as a potential evasion mechanism for tumor cells. Additionally, we aimed to assess the prognostic value of CD47 expression by examining its association with different clinicopathological factors. This study aimed to elucidate the significance of CD47 in the context of emerging anti-tumor targeting approaches.

METHODS

In this retrospective study, formalin-fixed paraffine-embedded (FFPE) tumor tissues of 55 treatment-naïve patients were evaluated by immunohistochemistry for the abundance of CD47 molecule on tumor cells. The categorization of CD47 positivity was as follows: 0 (no staining of tumor cells), 1 + (less than 1/3 of tumor area positive), 2 + (between 1/3 and 2/3 of tumor area positive), and 3 + (more than 2/3 of tumor area positive for CD47). Next, we compared CD47 abundance between different tumor grades (G1-3). We used Kaplan-Meier survival curves with log-rank test to analyze the differences in survival between patients with different CD47 expression. Moreover, we performed Cox proportional hazards regression model to evaluate the clinical significance of CD47.

RESULTS

CD47 is widely prevalent across distinct STS subtypes. More than 80% of high grade undifferentiated pleiomorphic sarcoma (UPS), 70% of myxofibrosarcoma (MFS) and more than 60% of liposarcoma (LPS) samples displayed a pattern of moderate-to-diffuse positivity. This phenomenon remains consistent regardless of the tumor grade. However, there was a tendency for higher CD47 expression levels in the G3 group compared to the combined G1 + G2 groups when all LPS, MFS, and UPS were analyzed together. No significant associations were observed between CD47 abundance, death, and metastatic status. Additionally, high CD47 expression was associated with a statistically significant increase in progression-free survival in the studied cohort of patients.

CONCLUSION

This study highlights the potential of the CD47 molecule as a promising immunotherapeutic target in STS, particularly given its elevated expression levels in diverse sarcoma types. Our data showed a notable trend linking CD47 expression to tumor grade, while also suggesting an interesting correlation between enhanced abundance of CD47 expression and a reduced hazard risk of disease progression. Although these findings shed light on different roles of CD47 in STS, further research is crucial to assess its potential in clinical settings.

SABR for Sarcoma Lung Metastases: Indications for Treatment and Guidance for Patient Selection

PURPOSE

The lungs are the most common site of metastasis for patients with soft tissue sarcoma. SABR is commonly employed to treat lung metastases among select patients with sarcoma with limited disease burden. We sought to evaluate outcomes and patterns of failure among patients with sarcoma treated with SABR for their lung metastases.

METHODS AND MATERIALS

We performed a retrospective review of patients treated at a tertiary cancer center between 2006 and 2020. Patient disease status at the time of SABR was categorized as either oligorecurrent or oligoprogressive. The Kaplan-Meier method was used to estimate disease outcomes. Uni- and multivariable analyses were conducted using the Cox proportional hazards model.

RESULTS

We identified 70 patients with soft tissue sarcoma treated with SABR to 98 metastatic lung lesions. Local recurrence-free survival after SABR treatment was 83% at 2 years. On univariable analysis, receipt of comprehensive SABR to all sites of pulmonary metastatic disease at the time of treatment was associated with improved progression-free survival (PFS; hazard ratio [HR], 0.51 [0.29-0.88]; P = .02). On multivariable analysis, only having systemic disease controlled at the time of SABR predicted improved PFS (median PFS, 14 vs 4 months; HR, 0.37 [0.20-0.69]; P = .002) and overall survival (median overall survival, 51 vs 14 months; HR, 0.17 [0.08-0.35]; P < .0001).

CONCLUSIONS

SABR provides durable long-term local control for sarcoma lung metastases. The most important predictor for improved outcomes was systemic disease control. Careful consideration of these factors should help guide decisions in a multidisciplinary setting to appropriately select the optimal candidates for SABR.

Generation of post-surgical minimal residual disease models to investigate metastasis in soft tissue sarcoma patient-derived orthotopic xenografts

Despite optimal multimodal treatment including surgical resection, 50%-80% of high-grade soft tissue sarcoma (STS) patients metastasize. Here, we present a protocol for the generation and use of post-surgical minimal residual disease models to investigate metastatic relapse in STS patient-derived xenografts. We describe steps for orthotopic engraftment of high-grade STS patient-derived tumor tissue. We then detail procedures for primary tumor resection with broad, negative resection margins and follow-up until metastases using MRI. For complete details on the use and execution of this protocol, please refer to Fischer et al. (2023).1.

Is perioperative chemotherapy effective in patients with localized myxoid liposarcoma?

BACKGROUND

This study aimed to compare the local recurrence, distant metastasis and disease-specific survival rates of patients with localized myxoid liposarcoma in the surgery and adjuvant chemotherapy group versus the surgery alone group.

METHODS

A total of 456 patients in the Japanese National Bone and Soft Tissue Tumour Registry database who had localized myxoid liposarcoma and underwent surgery and adjuvant chemotherapy or surgery alone between 2001 and 2019 were included in this retrospective study. The study adjusted for background differences between patients who underwent surgery and adjuvant chemotherapy (n = 228) or surgery alone (n = 228) using propensity score matching.

RESULTS

Univariate analysis showed no significant difference in local recurrence rate between the two groups (5-year local recurrence-free survival: 98.6% [95% confidence interval: 95.9-99.6] vs. 94.0% [95% confidence interval: 89.7-96.6], P = 0.052). Univariate analysis showed no difference in the incidence of distant metastases between the two groups (5-year distant metastasis-free survival: 80.5% [95% confidence interval: 73.9-85.8] vs. 75.1% [95% confidence interval: 67.7-81.2], P = 0.508). Univariate analysis showed no difference in disease-specific survival between the two groups (5-year disease-specific survival: 92.6% [95% confidence interval: 86.1-96.2] vs. 93.2% [95% confidence interval: 87.6-96.4], P = 0.804). In the high-risk group (n = 203) with high-grade tumours and tumour size ≥10 cm, there were no significant differences in the local recurrence, distant metastasis and disease-specific survival rates between the surgery and adjuvant chemotherapy group and the surgery alone group.

CONCLUSION

The effect of adjuvant chemotherapy on localized myxoid liposarcoma appears to be limited.

Right Thigh Mass Metastasis from Lung Cancer Mimicking Primary Soft Tissue Sarcoma: A Case Report

BACKGROUND Soft tissue metastases (STMs) are less common than bone metastases and sometimes misdiagnosed as primary soft tissue malignancies. Skin, lungs, and breast are the most common primary lesions of STMs and rarely the presenting symptoms. We present an STM from lung adenocarcinoma that became a presenting symptom in nonsmoking woman. CASE REPORT A 47-year-old woman presented to our hospital with a painful mass in her right thigh and weight loss of 10 kg for 4 months. Femoral radiograph revealed a lesion suggestive of bone sarcoma. However, magnetic resonance imaging (MRI) showed it was more likely a primary soft tissue sarcoma. A small mediastinal mass was noticed on preoperative chest radiograph, and the patient denied any symptoms except the mass in the right thigh. Our clinicopathological conference team decided to perform a biopsy of mediastinal and right thigh masses. Histopathology examinations confirmed the right thigh mass as soft tissue metastasis from mediastinal mass, confirmed as lung adenocarcinoma. We treated the patient with palliative care with zoledronic acid and gefitinib. At the 6-month follow-up, the patient's symptoms significantly improved, and MRI showed a marked size reduction. CONCLUSIONS Diagnosis of STM can be difficult when presenting as the primary manifestation. Failure to identify promptly can lead to rapid disease progression and unfavorable prognosis. Failure to diagnose primary malignancy during biopsy occurs in approximately 28% of cases. This report has the potential to facilitate the avoidance of unnecessary procedures and highlight the importance of using a multidisciplinary approach in managing cases with malignancy.

Pulmonary Amyloidoma Imitating Lung Cancer on 18 F-FDG PET/CT

ABSTRACT

Localized pulmonary amyloidosis forming a solitary mass known as "amyloidoma of the lung" is rare. Differentiation from lung cancer can be difficult due to suspicious features on CT and high 18 F-FDG uptake. We present a case of a 77-year-old woman with an incidental lung lesion on abdominal CT. Further evaluation with chest CT and 18 F-FDG PET/CT maintained the suspicion of lung cancer. However, histology revealed amyloidoma without signs of malignancy. Knowledge of imaging similarities between pulmonary amyloidomas and malignancies is important for interpreting 18 F-FDG PET/CT of lung tumors; however, only biopsy can confirm the rare differential diagnosis such as pulmonary amyloidoma.

[Current therapeutic standards in advanced soft tissue sarcomas]

Soft tissue sarcomas account for less than 1% of tumors in adults. With more than 80 different subtypes and often dismal prognosis, treatment of patients with soft tissue sarcomas is diagnostically and therapeutically complex. In patients with localized disease, surgery remains the mainstay of therapy. A multimodal approach consisting of neoadjuvant chemotherapy +/- regional hyperthermia may be suitable in patients with high-risk disease to maximize tumor shrinkage before surgery and to treat micrometastases. In patients with oligometastatic disease, local treatment options should be discussed within a specialized tumor board. In patients with disseminated metastatic disease, chemotherapy with anthracyclines remains the backbone of therapy. Immune checkpoint inhibitors have proven to be effective for patients with alveolar soft part sarcoma and targeted therapies with NTRK-inhibitors should be evaluated in patients with NTRK-fusions. This article focuses on current standards and developments in the treatment of soft tissue sarcomas.

Endometrial Sarcoma Metastasis to the Pterygopalatine Fossa: A Case Report and Review of the Literature

Metastatic skull base malignancies infrequently occur but, when present, typically arise from breast malignancies. Pterygopalatine fossa (PPF) metastasis of any malignancy is further seldom reported, and metastasis of gynecologic malignancies to the PPF has not been previously described in the literature. We present a single case of a 42-year-old female with the first likely case of high-grade endometrial sarcoma metastatic to the PPF. The patient presented with facial pain and numbness in the V2 distribution presented for evaluation. History was significant for several months of dysmenorrhea and metrorrhagia. Computed tomography, magnetic resonance imaging, and positron emission tomography imaging revealed a PPF mass with local extension and bony metastases. Endoscopic biopsy was performed, and final pathology was most consistent with metastatic high-grade endometrial stromal sarcoma. This is the first reported case of likely metastatic endometrial sarcoma to the PPF. This case report highlights the possibility of rare distant metastasis of gynecologic malignancy to this area of the skull base.

Atypical Spindle Cell/Pleomorphic Lipomatous Tumor

Atypical spindle cell/pleomorphic lipomatous tumor (ASCPLT) is a rare soft tissue neoplasm, commonly arising in the subcutis (more common than deep soft tissue) of limbs and limb girdles during mid-adulthood. ASCPLT is histologically a lipogenic neoplasm with ill-defined margins composed of a variable amount of spindle to pleomorphic/multinucleated cells within a fibromyxoid stroma. ASCPLTs lack MDM2 amplification, but a large subset show RB1 deletion and variable expression of CD34. Though initially thought to be the malignant form of spindle cell lipoma, ASCPLTs are benign with local recurrences (∼10-15%) and no well-documented dedifferentiation or metastasis.

Preoperative radiation therapy increases adherence in patients with high-risk extremity soft tissue sarcoma

BACKGROUND

Surgery and radiation therapy remain the standard of care for patients with high-grade extremity soft tissue sarcoma that are >5 cm. Radiation therapy is time and labor-intensive for patients, and social determinants of health may affect adherence. The aim of this study was to define demographic, clinical, and treatment factors associated with the completion of radiation therapy and determine if preoperative radiation therapy improved adherence compared to postoperative radiation therapy.

METHODS

The cohort included patients in the National Cancer Database with high-grade extremity soft tissue sarcoma >5 cm without nodal or distant metastases who received limb-sparing surgery and radiation therapy with microscopically negative R0 margins. Multivariable logistic regression analyses identified factors associated with radiation therapy sequencing and adherence (defined as completion of 50 Gy preoperative radiation therapy or at least 60 Gy postoperative radiation therapy). A multivariable Cox Proportional Hazards model assessed overall survival.

RESULTS

Among 2,145 patients, 47.1% received preoperative radiation therapy (n = 1,010), and 52.9% (n = 1135) received postoperative radiation therapy. A greater proportion of patients treated with preoperative (77.2%) versus postoperative radiation therapy (64.9%, P < .0001) received the recommended dose. More patients with private insurance (49.8% vs 35.3% Medicaid vs 44.9% Medicare, P = .011) and patients treated at an academic medical center (52.6% vs 47.4%, P < .001) received preoperative radiation therapy. Patients who received preoperative radiation therapy had lower odds of receiving insufficient doses of radiation therapy (odds ratio 0.34 [95% CI 0.27-0.47]). Neither radiation therapy adherence nor sequencing were independent predictors of overall survival.

CONCLUSIONS

Patients who received preoperative radiation therapy were more likely to complete therapy and receive an optimal dose than patients treated with postoperative radiation therapy. Preoperative radiation therapy improves adherence and should be widely considered in patients with high-grade extremity soft tissue sarcoma, particularly in patients at risk for not completing therapy.

GLI1-Altered Mesenchymal Tumors

GLI1-altered mesenchymal tumors comprise an emerging group of neoplasms characterized by fusions or amplifications involving GLI1, a gene that encodes a key regulator of the Hedgehog signaling pathway. In recent years, tumors with GLI1 alterations have been reported across a variety of anatomic sites and a broad age range. Although these tumors can exhibit a wide morphologic spectrum and a variable immunophenotype, they frequently present with monomorphic ovoid cells arranged in distinctive nests with a rich, arborizing vascular network. Recent evidence indicates that they have the potential to metastasize, which suggests that they may be best considered a sarcoma.

Superficial CD34-Positive Fibroblastic Tumor

Superficial CD34-positive fibroblastic tumor is a mesenchymal neoplasm of "intermediate malignancy" recently included in the fifth edition of the World Health Organization classification of soft tissue and bone tumors. In this review, we summarize the current knowledge on this rare entity with a special focus on its clinicopathological features, morphologic spectrum, and differential diagnosis. We also provide data regarding recent discoveries on its molecular profile and discuss its prognosis and management.

Myxoinflammatory Fibroblastic Sarcoma

MIFS is a low-grade fibroblastic sarcoma that predilects to superficial distal extremity soft tissue. It is composed of plump spindled and epithelioid cells, inflammatory infiltrates, and mucin deposits in a fibrosclerotic stroma. Large epithelioid cells harboring bizarre nuclei and virocyte-like macronucleoli and pleomorphic pseudolipoblasts are characteristic. While conventional MIFS has locally recurrent potential but minimal metastatic risk, tumors with high-grade histologic features have a greater risk for recurrence and metastasis. Wide local excision is the recommended treatment.

The utility of FISH analysis in the diagnosis of BCOR-rearranged sarcomas

BACKGROUND

A BCL6 corepressor (BCOR) gene alteration is a genetic signature of rare subsets of sarcomas. The identification of this alteration has recently contributed to the definition of new entities in the current WHO (2020) classification of soft tissue and bone tumours. We retrospectively examined cases of BCOR-rearranged sarcoma (BRS) to assess the reliability of the BCOR FISH analysis using an IVD (in vitro diagnostic) probe.

METHODS

We investigated and compared the molecular diagnostic strategies and features by collecting 17 data from patients with a BCOR gene rearrangement detected using quantitative-Reverse Transcription-Polymerase Chain Reaction (qRTPCR), Next-Generation Sequencing (NGS) and Fluorescence in situ hybridization (FISH).

RESULTS

We describe fourteen BCOR::CCNB3 sarcomas, one spindle cell sarcoma with a novel BCOR::MAML1 fusion, one spindle cell sarcoma with a novel BCOR::AHR fusion, and one ossifying fibromyxoid tumour with a BCOR::ZC3H7B fusion. FISH analysis of all, except one, BCOR::CCNB3 sarcoma, showed a FISH break-apart pattern with mild signal separation. The MAML1::BCOR sarcoma showed large-space split signals, while in the two patients with AHR::BCOR and ZC3H7B::BCOR fusions, no BCOR rearrangement was observed using FISH.

CONCLUSIONS

Our study indicates that BCOR FISH analysis using an IVD probe, may be useful to detect the presence of a BCOR rearrangement, including both translocations and inversions; however, negative results, in some cases, can occur.

Inflammatory Rhabdomyoblastic Tumor: From a Nebulous Smooth Muscle Neoplasm to a Novel Skeletal Muscle Tumor Subtype

Inflammatory rhabdomyoblastic tumor is a recently introduced name for neoplasms currently included in the World Health Organization classification of soft tissue tumors under the rubric inflammatory leiomyosarcoma. Inflammatory rhabdomyoblastic tumor is an excellent example of how surgical pathologists working in conjunction with tumor biologists can greatly improve tumor classification to the benefit of patients. Over the last 28 years, understanding of this entity has undergone a fascinating evolution. This review serves as a summary of the latest findings in inflammatory rhabdomyoblastic tumor research and a diagnostic manual for the practicing surgical pathologist.

Development and external validation of a machine learning model for prediction of survival in undifferentiated pleomorphic sarcoma

PURPOSE

Machine learning (ML) algorithms to predict cancer survival have recently been reported for a number of sarcoma subtypes, but none have investigated undifferentiated pleomorphic sarcoma (UPS). ML is a powerful tool that has the potential to better prognosticate UPS.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was queried for cases of histologically confirmed undifferentiated pleomorphic sarcoma (UPS) (n = 665). Patient, tumor, and treatment characteristics were recorded, and ML models were developed to predict 1-, 3-, and 5-year survival. The best performing ML model was externally validated using an institutional cohort of UPS patients (n = 151).

RESULTS

All ML models performed best at the 1-year time point and worst at the 5-year time point. On internal validation within the SEER cohort, the best models had c-statistics of 0.67-0.69 at the 5-year time point. The Multi-Layer Perceptron Neural Network (MLP) model was the best performing model and used for external validation. Similarly, the MLP model performed best at 1-year and worst at 5-year on external validation with c-statistics of 0.85 and 0.81, respectively. The MLP model was well calibrated on external validation. The MLP model has been made publicly available at https://rachar.shinyapps.io/ups_app/ .

CONCLUSION

Machine learning models perform well for survival prediction in UPS, though this sarcoma subtype may be more difficult to prognosticate than other subtypes. Future studies are needed to further validate the machine learning approach for UPS prognostication.

NR1D1-rearranged soft tissue tumour: A clinicopathological and molecular analysis of four additional cases

AIMS

Nuclear receptor subfamily 1 group D member 1 (NR1D1)-rearranged soft tissue tumour is a newly described entity with an epithelioid morphology and a potential for aggressive behaviour. Largely due to under-recognition, this tumour type has not yet been widely acknowledged. Herein, we report four additional cases to further expand its clinicopathological and molecular spectrum.

METHODS AND RESULTS

Four mesenchymal tumours with NR1D1 rearrangement were identified from our consultation files. There were one male and three females with ages ranging from 19 to 47 years (median = 28.5 years). Tumour occurred in the tongue, neck, hip and index finger, respectively. Histologically, two tumours were composed predominantly of epithelioid cells; one tumour had admixed epithelioid-spindle cells and one tumour consisted of monomorphic small round to ovoid cells. By immunohistochemistry, none of the tumours expressed lineage-specific markers. Targeted RNA-sequencing identified NR1D1 fusions in all four tumours, the partner genes being MAML2, MAML3, KMT2A and NCOA2, respectively. The novel MAML3 and NCOA2 rearrangements were confirmed by fluorescence in-situ hybridisation analysis. On follow-up (2-23 months), one patient experienced local recurrence due to incomplete resection and one patient developed lung metastasis. The other two patients were alive without disease.

CONCLUSIONS

This study adds more support for NR1D1-rearranged soft tissue tumour as an emerging entity. The occurrence of two additional tumours in the head and neck region, description of a small round cell variant and identification of novel MAML3, KMT2A and NCOA2 partners further expand its clinicopathological and molecular spectrum. More studies on larger series are necessary to validate the fully malignant potential of NR1D1-rearranged soft tissue tumour.

Xanthogranulomatous Epithelial Tumors and Keratin-Positive Giant Cell Rich Tumors of Soft Tissue and Bone: Two Sides of the Same Coin

Xanthogranulomatous epithelial tumor is a recently described soft tissue tumor characterized by subcutaneous location, partial encapsulation, a xanthogranulomatous inflammatory cell infiltrate, and keratin-positive mononuclear cells. It shares some morphologic features with keratin-positive, giant cell-rich soft tissue tumors. Both have recently been shown to harbor HMGA2::NCOR2 fusions. The relationship between these tumors and their differential diagnosis with other osteoclast-containing soft tissue tumors is discussed.

Spindle cell neoplasms with novel LTK fusion - Expanding the spectrum of kinase fusion-positive soft tissue tumors

AIMS

Kinase fusion-positive soft tissue tumors represent an emerging, molecularly defined group of mesenchymal tumors with a wide morphologic spectrum and diverse activating kinases. Here, we present two cases of soft tissue tumors with novel LTK fusions.

METHODS AND RESULTS

Both cases presented as acral skin nodules (big toe and middle finger) in pediatric patients (17-year-old girl and 2-year-old boy). The tumors measured 2 and 3 cm in greatest dimension. Histologically, both cases exhibited bland-looking spindle cells infiltrating adipose tissue and accompanied by collagenous stroma. One case additionally displayed perivascular hyalinization and band-like stromal collagen. Both cases exhibited focal S100 staining, and one case had patchy coexpression of CD34. Targeted RNA-seq revealed the presence of novel in-frame MYH9::LTK and MYH10::LTK fusions, resulting in upregulation of LTK expression. Of interest, DNA methylation-based unsupervised clustering analysis in one case showed that the tumor clustered with dermatofibrosarcoma protuberans (DFSP). One tumor was excised with amputation with no local recurrence or distant metastasis at 18-month follow-up. The other case was initially marginally excised with local recurrence after one year, followed by wide local excision, with no evidence of disease at 10 years of follow-up.

CONCLUSIONS

This is the first reported case series of soft tissue tumors harboring LTK fusion, expanding the molecular landscape of soft tissue tumors driven by activating kinase fusions. Furthermore, studies involving a larger number of cases and integrated genomic analyses will be warranted to fully elucidate the pathogenesis and classification of these tumors.

Current updates in sarcoma biomarker discovery: emphasis on next-generation sequencing-based methods

Soft tissue sarcomas comprise a heterogeneous group of neoplasms. Although soft tissue malignancies make up only 2% of adult cancers, classification based on histomorphology presents a diagnostic challenge. Characterisation of soft tissue sarcomas by molecular analysis is rapidly evolving to improve diagnostic accuracy and develop targeted therapies. This review highlights the advances in molecular techniques, including current next-generation sequencing-based assays (fusion detection by RNA sequencing, targeted/whole exome sequencing, microRNA profiling), as well as emerging methods (liquid biopsies, DNA methylation profiling, single-cell molecular profiling and next-generation immunohistochemistry) for future clinical applications.

Sclerosing Epithelioid Fibrosarcoma

Sclerosing epithelioid fibrosarcoma (SEF) is a distinctive sarcoma that may arise in nearly any soft tissue site or bone. While there has been past controversy as to whether it is related to low-grade fibromyxoid sarcoma (LGFMS), it has been shown to behave far more aggressively than LGFMS. SEF has a propensity to metastasize to the lungs and bone and arise within the abdominal cavity. Histologically, it is characterized by uniform nuclei embedded in a densely collagenous stroma simulating osteoid. By immunohistochemistry, it is often strongly positive for MUC4. The majority (75%) have EWSR1 gene rearrangement, most commonly with CREB3L1 as a fusion partner, although a variety of FUS/EWSR1 and CREB3L1/CREB3L2/CREB3L3 fusions have been described in addition to others. SEF is currently recalcitrant to nearly all chemotherapy and radiation therapy.

Calcified Chondroid Mesenchymal Neoplasms

Calcified chondroid mesenchymal neoplasms (CCMN) represent a morphologic spectrum of related tumors. Historically, chondroid matrix or chondroblastoma-like features have been described in soft tissue chondroma, tenosynovial giant cell tumors (especially of the temporomandibular joint (TMJ) region), and in a subset of tophaceous pseudogout. Recently, these tumors have been found to share FN1-receptor tyrosine kinase (RTK) fusions. This review discusses the clinical, morphologic, immunohistochemical, and molecular genetic features of CCMN. The distinction from morphologic mimics is also discussed.

Pulmonary arterial sarcoma: A case report

RATIONALE

Pulmonary artery sarcoma (PAS) is a rare malignant tumor primarily originating from the pulmonary artery's intima or subintima. Approximately one-third of cases are classified as undifferentiated type. Its clinical manifestations lack specificity, dyspnea is the main symptom but can also present with chest pain, cough, hemoptysis, and other discomforts, making it prone to misdiagnosis as pulmonary embolism (PE).

PATIENT CONCERNS

A 50-year-old woman was admitted to the hospital with "dyspnea for more than 3 months, aggravated for 2 days," and computed tomography pulmonary angiography suggesting "bilateral multiple pulmonary embolisms."

DIAGNOSES

The patient was initially misdiagnosed as PE, and was later definitively diagnosed as undifferentiated pleomorphic sarcoma of the pulmonary artery by pathologic biopsy.

INTERVENTIONS AND OUTCOMES

The patient was initially treated with anticoagulant therapy, but her dyspnea was not relieved. After that, she underwent positron emission computed tomography (PET-CT) and other investigations, which suggested the possibility of PAS, and then she underwent pulmonary endarterectomy to remove the lesion, which relieved her symptoms and was advised to seek further medical attention from the Department of Oncology and Department of Radiotherapy.

LESSONS

PAS can be easily misdiagnosed as PE. If a diagnosis of PE is made, but anticoagulation or even thrombolytic therapy proves ineffective, and there is no presence of PE causative factors such as deep vein thrombosis in the lower extremities, or D-dimer levels are not high, one should be cautious and consider the possibility of PAS.

Primary soft tissue sarcoma breast with multiphenotypic differentiation

Primary soft tissue sarcomas of the breast are rare aggressive neoplasms. These often are misdiagnosed with other more common neoplasms like fibroepithelial malignancies, namely phyllodes tumour and metaplastic carcinoma. Being uncommon, chances of being misdiagnosed are higher leading to early mortality. A multidisciplinary team incorporating surgery, pathology, chemotherapy and radiotherapy is required to formulate an approach to primary soft tissue sarcoma. Generally, these tumours may show single or dual phenotype; we present one rare case report showing multiphenotypic differentiation.

A 50-Year-Old Man Presenting with Multiple Bone Lesions and a Diagnosis of Phosphaturic Mesenchymal Tumor of the Femur

BACKGROUND Phosphaturic mesenchymal tumor (PMT) is an extremely rare mesenchymal neoplasm that is commonly seen in bone and soft tissue. It is associated with a paraneoplastic syndrome, oncogenic osteomalacia, due to tumor-induced urinary phosphate wasting. It is demonstrated to be predominantly mediated by fibroblast growth factor 23 (FGF23)/fibroblast growth factor receptor 1 (FGFR1) axis. Clinically, PMT usually presents as a solitary lesion in the bone. The diagnosis of PMT is challenging due to its non-specific clinical manifestation, radiologic findings, and morphological features. CASE REPORT We report the case of a 50-year-old man presenting with multiple lytic bone lesions and associated pathologic fracture of the right femur, clinically suspicious for multiple myeloma or other metastatic malignant process. Resection from the right femur showed a hypercellular lesion composed of oval-to-spindled cells infiltrating the native trabecular bone with admixed multinucleated giant cells. Immunohistochemical (IHC) staining and in situ hybridization (ISH) demonstrated the tumor cells were positive for SATB2, ERG, FGFR1, and FGF23 ISH. DNA and RNA next-generation sequencing showed marked increases in mRNA levels of FGF23 and FGFR1. The constellation of clinicoradiologic, histomorphologic, IHC, and molecular findings supported a diagnosis of primary benign PMT. CONCLUSIONS This case report discusses a patient with PMT presenting with multifocal lesions due to tumor-induced osteomalacia at initial presentation. We hope that this report will increase the awareness of clinician and pathologists of PMT as a differential diagnosis in patients presenting with multifocal lytic bone lesions. In turn, this will prevent misdiagnosis and overtreatment of a typically benign process.

Proteomic characterization identifies clinically relevant subgroups of soft tissue sarcoma

Soft tissue sarcoma is a broad family of mesenchymal malignancies exhibiting remarkable histological diversity. We portray the proteomic landscape of 272 soft tissue sarcomas representing 12 major subtypes. Hierarchical classification finds the similarity of proteomic features between angiosarcoma and epithelial sarcoma, and elevated expression of SHC1 in AS and ES is correlated with poor prognosis. Moreover, proteomic clustering classifies patients of soft tissue sarcoma into 3 proteomic clusters with diverse driven pathways and clinical outcomes. In the proteomic cluster featured with the high cell proliferation rate, APEX1 and NPM1 are found to promote cell proliferation and drive the progression of cancer cells. The classification based on immune signatures defines three immune subtypes with distinctive tumor microenvironments. Further analysis illustrates the potential association between immune evasion markers (PD-L1 and CD80) and tumor metastasis in soft tissue sarcoma. Overall, this analysis uncovers sarcoma-type-specific changes in proteins, providing insights about relationships of soft tissue sarcoma.

Indeterminate pulmonary nodules in non-rhabdomyosarcoma soft tissue sarcoma: A study of the European paediatric Soft Tissue Sarcoma Study Group

BACKGROUND

The aim of this study was to assess the clinical impact of indeterminate pulmonary nodules (no more than four pulmonary nodules of less than 5 mm or one nodule measuring between 5 and less than 10 mm by computed tomography [CT]) in children and adolescents with adult-type non-rhabdomyosarcoma soft tissue sarcoma (NRSTS) at diagnosis.

METHODS

Patients with NRSTS treated in 11 centers as part of the European paediatric Soft Tissue Sarcoma Study Group (EpSSG) were retrospectively assessed. Local radiologists, blinded to clinical information except for patients' age and tumor histotype, reviewed the chest CT at diagnosis and filled out a case report form. Because patients with or without indeterminate nodules in the EpSSG NRSTS 2005 study received the same type of treatment, event-free survival (EFS) and overall survival (OS) between groups by log-rank test were compared.

RESULTS

Overall, 206 patients were examined: 109 (52.9%) were without any nodules, 78 (38%) had at least one indeterminate nodule, and 19 (9.2%) had nodules meeting the definition of metastases, which were then considered to be misclassified and were excluded from further analyses. Five-year EFS was 78.5% (95% CI, 69.4%-85.1%) for patients without nodules and 69.6% (95% CI, 57.9%-78.7%) for patients with indeterminate nodules (p = .135); 5-year OS was 87.4% (95% CI, 79.3%-92.5%) and 79.0% (95% CI, 67.5%-86.8%), respectively (p = .086).

CONCLUSIONS

This study suggests that survival does not differ in otherwise nonmetastatic patients with indeterminate pulmonary nodules compared to nonmetastatic patients without pulmonary nodules.

PLAIN LANGUAGE SUMMARY

Radiologists should be aware of the classification of indeterminate pulmonary nodules in non-rhabdomyosarcoma soft tissue sarcomas and use it in their reports. More than a third of patients with non-rhabdomyosarcoma soft tissue sarcoma can be affected by indeterminate pulmonary nodules. Indeterminate pulmonary nodules do not significantly affect the overall survival of pediatric patients with non-rhabdomyosarcoma soft tissue sarcoma.

Explainable Model Using Shapley Additive Explanations Approach on Wound Infection after Wide Soft Tissue Sarcoma Resection: "Big Data" Analysis Based on Health Insurance Review and Assessment Service Hub

Background and Objectives: Soft tissue sarcomas represent a heterogeneous group of malignant mesenchymal tissues. Despite their low prevalence, soft tissue sarcomas present clinical challenges for orthopedic surgeons owing to their aggressive nature, and perioperative wound infections. However, the low prevalence of soft tissue sarcomas has hindered the availability of large-scale studies. This study aimed to analyze wound infections after wide resection in patients with soft tissue sarcomas by employing big data analytics from the Hub of the Health Insurance Review and Assessment Service (HIRA). Materials and Methods: Patients who underwent wide excision of soft tissue sarcomas between 2010 and 2021 were included. Data were collected from the HIRA database of approximately 50 million individuals' information in the Republic of Korea. The data collected included demographic information, diagnoses, prescribed medications, and surgical procedures. Random forest has been used to analyze the major associated determinants. A total of 10,906 observations with complete data were divided into training and validation sets in an 80:20 ratio (8773 vs. 2193 cases). Random forest permutation importance was employed to identify the major predictors of infection and Shapley Additive Explanations (SHAP) values were derived to analyze the directions of associations with predictors. Results: A total of 10,969 patients who underwent wide excision of soft tissue sarcomas were included. Among the study population, 886 (8.08%) patients had post-operative infections requiring surgery. The overall transfusion rate for wide excision was 20.67% (2267 patients). Risk factors among the comorbidities of each patient with wound infection were analyzed and dependence plots of individual features were visualized. The transfusion dependence plot reveals a distinctive pattern, with SHAP values displaying a negative trend for individuals without blood transfusions and a positive trend for those who received blood transfusions, emphasizing the substantial impact of blood transfusions on the likelihood of wound infection. Conclusions: Using the machine learning random forest model and the SHAP values, the perioperative transfusion, male sex, old age, and low SES were important features of wound infection in soft-tissue sarcoma patients.