BACKGROUND: Solitary fibrous tumor (SFT) is a remarkably uncommon mesenchymal tumor. STAT6 level and a combination of clinical, pathological, and molecular features are required to arrive at a proper diagnosis.
METHODS: In this report, we present an intriguing case involving a 43-year-old woman who initially exhibited symptoms of a bleeding retroperitoneal tumor, initially resembling a gastrointestinal stromal tumor, but later confirmed as an SFT. However, a year later, what was initially believed to be a recurrence of her SFT was instead identified as a desmoid tumor.
CONCLUSIONS: Distinguishing SFT from other tumors was pivotal. Correcting misdiagnoses of tumor type initially and of recurrence later was necessary for appropriate treatment of the correct desmoid type.

OBJECTIVE: To investigate the value of multi-parametric MRI-based radiomics for preoperative prediction of lung metastases from soft tissue sarcoma (STS).
METHODS: In total, 122 patients with clinicopathologically confirmed STS who underwent pretreatment T1-weighted contrast-enhanced (T1-CE) and T2-weighted fat-suppressed (T2FS) MRI scans were enrolled between Jul. 2017 and Mar. 2021. Radiomics signatures were established by calculating and selecting radiomics features from the two sequences. Clinical independent predictors were evaluated by statistical analysis. The radiomics nomogram was constructed from margin and radiomics features by multivariable logistic regression. Finally, the study used receiver operating characteristic (ROC) and calibration curves to evaluate performance of radiomics models. Decision curve analyses (DCA) were performed to evaluate clinical usefulness of the models.
RESULTS: The margin was considered as an independent predictor (p < 0.05). A total of 4 MRI features were selected and used to develop the radiomics signature. By incorporating the margin and radiomics signature, the developed nomogram showed the best prediction performance in the training (AUCs, margin vs. radiomics signature vs. nomogram, 0.609 vs. 0.909 vs. 0.910) and validation (AUCs, margin vs. radiomics signature vs. nomogram, 0.666 vs. 0.841 vs. 0.894) cohorts. DCA indicated potential usefulness of the nomogram model.
CONCLUSIONS: This feasibility study evaluated predictive values of multi-parametric MRI for the prediction of lung metastasis, and proposed a nomogram model to potentially facilitate the individualized treatment decision-making for STSs.

The coronavirus disease (COVID-19) pandemic negatively affected the diagnosis and treatment of several cancer types. However, this pandemic\'s exact impact and extent on bone and soft tissue sarcomas need to be clarified. We aimed to investigate the effect of the COVID-19 pandemic and emergency declaration by the local government on consultation behavior and clinical stage at diagnosis of bone and soft tissue sarcoma. A total of 403 patients diagnosed with bone and soft tissue sarcoma who initially visited three sarcoma treatment hospitals between January 2018 and December 2021 were included. The monthly number of newly diagnosed soft tissue sarcoma patients was reduced by 25%, and the proportion of soft tissue patients with stage IV disease at diagnosis significantly increased by 9% during the COVID-19 pandemic compared to before the COVID-19 pandemic. Furthermore, the monthly number of new primary bone and soft tissue sarcoma patients significantly decreased by 43% during the state of emergency declaration. The COVID-19 pandemic had a negative impact on soft tissue sarcoma patients\' consultation behavior and increased the proportion of advanced-stage patients at initial diagnosis. An emergency declaration by the local government also negatively affected primary bone and soft tissue sarcoma patients\' consultation behavior.

UNASSIGNED: Improved prognostic tools are needed for patients with locally recurrent extremity or truncal soft tissue sarcoma (STS).
UNASSIGNED: To examine the association between average local recurrence (LR) growth rate and outcomes following resection of locally recurrent extremity or truncal STS.
UNASSIGNED: This retrospective cohort study used a prospectively maintained database from a single high-volume tertiary sarcoma referral center in the US to identify patients 16 years of age or older who underwent repeat resection of a locally recurrent extremity or truncal STS between July 1, 1982, and December 31, 2021. Patients with atypical lipomatous tumors, desmoid tumors, dermatofibrosarcoma protuberans, angiosarcomas, and prior or synchronous distant recurrence were excluded. Data were analyzed from November 1, 2022, to June 17, 2024.
UNASSIGNED: Average LR growth rate, defined as the sum of recurrent tumor maximal diameters divided by the disease-free interval after index operation.
UNASSIGNED: The primary outcomes were cumulative incidences of disease-specific death (DSD), with death from other causes as a competing risk, and second LR, with death from any cause as a competing risk.
UNASSIGNED: The study cohort included 253 patients (median [IQR] age, 64 [51-73] years; 140 [55.3%] male). The 5-year cumulative incidence of DSD after repeat resection was 29%. Multivariable analysis indicated that LR growth rate (hazard ratio [HR], 1.12 [95% CI, 1.08-1.18]; P < .001), younger age (HR, 0.98 [95% CI, 0.97-0.99]; P = .002), R1 or R2 margins (HR, 1.71 [95% CI, 1.03-2.84]; P = .04), high LR grade (HR, 2.90 [95% CI, 1.17-7.20]; P = .02), and multifocality (HR, 2.92 [95% CI, 1.70-5.00]; P < .001) were independently associated with higher incidence of DSD. Using the minimum P value method, the optimal cutoff for growth rate was found to be 0.68 cm/mo. Patients with values above this cutoff had higher 5-year incidences of DSD following repeat resection (63% vs 19%; permutation test P < .001) and higher amputation rates (19% vs 7%; P = .008). Only R1 margins were independently associated with higher incidence of second LR (HR, 1.81 [95% CI, 1.19-2.78]; P = .006).
UNASSIGNED: In this cohort study of patients undergoing resection of a locally recurrent extremity or truncal STS, LR growth rate was independently associated with DSD. These findings suggest that patients with growth rates higher than 0.68 cm/mo who undergo LR resection may have high disease-specific mortality and amputation rates and should be considered for perioperative systemic therapy.

BACKGROUND: Early detection of soft tissue sarcoma (STS) recurrence is essential; however, the role and timeline of Magnetic resonance imaging (MRI) surveillance are still under debate. The aim of this study was to determine whether local recurrence (LR) could be identified via clinical examination alone and to assess the MRI morphology of primary STS and LR.
METHODS: This retrospective study included all patients with STS recurrence after surveillance for at least five years from the tumor database of the Medical University of Vienna from 2000 until December 2023. The characteristics of primary STS and LR and the time interval to recurrence and clinical detectability were assessed. The MRIs of LR and posttherapeutic changes (PTC) were compared with the initial MRIs.
RESULTS: A total of 57 patients (60% male; mean age 58.5 ± 18.0 years) with STS and histologically confirmed LR were included. The mean time interval to LR was 2.3 ± 1.8 years (range 108 to 3037 days). The clinically detectable recurrences were significantly larger than the inapparent ones (71.9 cm3 vs. 7.0 cm3; p < 0.01). The MRI morphology of all LRs (26/26) closely resembled the initial STS. For comparison, nine patients were included with clinically suspected LRs, which were histologically proven to be PTC. None of these resembled the primary STS.
CONCLUSIONS: Based on clinical symptoms alone, especially small and early recurrences can be missed, which supports the importance of MRI surveillance.

OBJECTIVE: Benign and tumor-like lesions of the hindfoot and ankle are common, whereas malignant entities are rare. Accurate evaluation and timely management of these lesions can be challenging, making it crucial to understand their incidence and anatomic localization. This study retrospectively analyzed the distribution of benign and malignant bone and soft tissue tumors in the hindfoot and ankle.
METHODS: This study included patient data from a single center, such as age, sex, histologic diagnosis, and anatomic location over a 12.5 year period.
RESULTS: Of the 105 cases reviewed, 19 cases (18.1%) were osseous lesions and 86 cases (81.9%) were soft tissue lesions. The latter were divided into 77 benign and 9 malignant cases, resulting in an overall malignancy rate of 8.6%. The most common osseous lesion was the intraosseous ganglion (n=12). The majority of benign soft tissue lesions (75.3%) were located in the hindfoot, with TGCT, schwannoma, and ganglion cysts being the most common types. The nine malignant cases were distributed among seven entities and were evenly distributed among both regions and sexes. Malignant cases had a higher mean age (59.2 years) compared to benign cases (40.8 years; p=0.001).
CONCLUSIONS: Tumors, tumor-like lesions, and pseudotumors represent an important aspect of ankle pathology. The majority of focal masses and swellings are benign soft tissue or osseous lesions, but malignant entities can occur and may be mistaken for benign conditions. Preoperative imaging and histopathologic examination are essential, and preoperative presentation to a multidisciplinary tumor board is recommended in unclear cases.

BACKGROUND: Myxofibrosarcoma is a myxoid soft tissue sarcoma showing T2 high intensity on magnetic resonance imaging. However, myxofibrosarcoma is a heterogeneous sarcoma with both myxoid and cellular portions. Magnetic resonance imaging findings were obtained MRI findings for comparison with histological and Ki-67 immunohistochemical features, in different portions of one myxofibrosarcoma.
METHODS: Magnetic resonance imaging observations were compared with gross pathological and microscopic findings of a myxofibrosarcoma from a 50-year-old Japanese female. The Ki-67 labeling indices of different portions of the tumor, that is, the myxoid, cellular, and histologically confirmed infiltrative margin portions (pathological tail sign), were compared. The T2 low intensity area was more cellular than the T2 high intensity area, while the cellular portion had a significantly higher Ki-67 index than the myxoid portion (p = 0.0313). The portions with the pathological tail sign had a significantly higher Ki-67 labeling index than those without this sign (p = 0.0313).
CONCLUSIONS: More cellular portions of a myxofibrosarcoma correspond to more areas of the tumor showing aggressive features. Furthermore, our data also support the hypothesis of high aggressiveness being associated with the pathological tail sign in myxofibrosarcoma. To our knowledge, this is the first case report to describe comparisons among the imaging findings, histological features, and Ki-67 immunohistochemistry results for different portions of one myxofibrosarcoma.

Dedifferentiated liposarcoma (DDLPS) is a non-lipogenic sarcoma, generally arising from well-differentiated liposarcoma (WDLPS), although it can develop de novo. DDLPS tumors rarely trans-differentiate into non-adipose mesenchymal tissues; however, the latter lack notable variety and mostly show striated muscle or osteogenic/chondrogenic differentiation. Here, we report a case of DDLPS that contained numerous atypical vessels. A man in his sixties presented with a large tumor in his right thigh, and the tumor was surgically resected. Microscopically, most of the tumor was WDLPS, but a minor portion showed DDLPS, consisting of high-grade spindle cells. Remarkably, the DDLPS contained vessels of various sizes with atypical cytoarchitecture, including vessels with seemingly muscular layers. Immunohistochemically, the atypical cells within the vascular wall expressed aSMA, consistent with smooth muscle cells or pericytes, whereas surrounding high-grade spindle cells only focally expressed it, and these aSMA-positive cells within the vessels exhibited MDM2 amplification by immuno-fluorescence in situ hybridization. Our results demonstrate that DDLPS can trans-differentiate into smooth muscle cells of various-sized accompanying vessels, which may support their survival and proliferation.

BACKGROUND: Radiotherapy improves local tumour control in patients with soft tissue sarcoma of the extremities (STSE) but it also increases the probability of long-term toxicities such as tissue fibrosis, joint stiffness and lymphoedema. The use of radiation dose and volume thresholds, called dose constraints, may potentially reduce the development of toxicities in STSE. The aim of this study is to determine predictors of radiotherapy-related side effects for STSE.
METHODS: Predicting radiotherapy response, Toxicities and quality-of-life related functional outcomes in soft tissue sarcoma of the extremities (PredicT) is a multicentre observational study comprising two cohorts (PredicT A and B). PredicT A, a retrospective analysis of the UK VorteX (NCT00423618) and IMRiS clinical trials (NCT02520128), is aimed at deriving a statistical model for development of dose-volume constraints. This model will use receiving operator characteristics and multivariate analysis to predict radiotherapy side effects and patient-reported outcomes. PredicT B, a prospective cohort study of 150 patients with STSE, is aimed at testing the validity of those dose-volume constraints. PredicT B is open and planned to complete recruitment by September 2024.
BACKGROUND: PredicT B has received ethical approval from North West - Liverpool Central Research Ethics Committee (20/NW/0267). Participants gave informed consent to participate in the study before taking part. We will disseminate our findings via publications, presentations, national and international conference meetings and engage with local charities.
BACKGROUND: NCT05978024.

Ectomesenchymal chondromyxoid tumor (ECT) is a rare soft tissue tumor with peculiar histogenesis, exhibiting a predilection for the dorsum of the tongue. Molecular evidence suggests that it may originate from the migration of ectomesenchymal pluripotent cells from the neural crest to the tongue, where these cells may eventually proliferate and undergo myxoid and chondroid differentiation. This article illustrates a case of a 16-year-old female patient who presented with a nodule on the dorsum of her tongue, which had been present for four years. Surgical excision was performed, and histopathological analysis revealed a myxoid neoplasia composed of polygonal and spindle cells within a loose stroma containing chondroid areas. Tumor cells were positive for GFAP and S-100 proteins on immunohistochemical study, confirming the diagnosis of ECT. After a 5-year follow-up, the patient has shown no evidence of recurrence. Although rare, ECT can be diagnosed straightforwardly due to its distinctive clinical, histopathological, and immunohistochemical features. Clinicians and pathologists should become familiar with this tumor in order to avoid misdiagnosis.