Myxoid soft-tissue neoplasms: comprehensive update of the taxonomy and MRI features. AJR Am J Roentgenol. 2015;204:374-385. [PMID: 25615761 DOI: 10.2214/ajr.14.12888]

MRI Radiomics Analysis in the Diagnostic Differentiation of Malignant Soft Tissue Myxoid Sarcomas From Benign Soft Tissue Musculoskeletal Myxomas

BACKGROUND

Differentiation of benign myxomas and malignant myxoid sarcomas can be difficult with an overlapping spectrum of morphologic MR findings.

PURPOSE

To assess the diagnostic utility of MRI radiomics in the differentiation of musculoskeletal myxomas and myxoid sarcomas.

STUDY TYPE

Retrospective.

POPULATION

A total of 523 patients were included; histologically proven myxomas (N = 201) and myxoid sarcomas (N = 322), randomly divided (70:30) into training:test subsets.

SEQUENCE/FIELD STRENGTH

T1-weighted (T1W), T2-weighted fat-suppressed (fluid-sensitive), and T1-weighted post-contrast (T1W + C) sequences at 1.0 T, 1.5 T, or 3.0 T.

ASSESSMENT

Seven semantic (qualitative) tumor features were assessed in each case. Manual 3D tumor segmentations performed with radiomics features extracted from T1W, fluid-sensitive, and T1W + C acquisitions. Models were constructed based on radiomic features from individual sequences and from their combination, both with and without the addition of qualitative tumor features.

STATISTICAL TESTS

Intraclass correlation evaluated in 60 cases segmented by three readers. Features with intraclass correlation <0.7 excluded from further analysis. Boruta feature selection and Random Forest modeling performed using the training-dataset, with resultant models used to assess class discrimination (myxoma vs. myxoid sarcoma) in the test dataset. Radiomics score defined as probability class = myxoma. Logistic regression modeling employed to estimate performance of the radiomics score. Area under the receiver operating characteristic curve (AUC) was used to assess diagnostic performance, and DeLong's test to assess performance between constructed models. A P-value <0.05 was considered significant.

RESULTS

Four qualitative semantic features showed significant predictive power in class discrimination. Radiomic models demonstrated excellent differentiation of myxomas from myxoid sarcomas: AUC of 0.9271 (T1W), 0.9049 (fluid-sensitive), and 0.9179 (T1W + C). Incorporation of multiparametric data or semantic features did not significantly improve model performance (P ≥ 0.08) compared to radiomic models derived from any individual MRI sequence alone.

DATA CONCLUSION

MRI radiomics appears to be accurate in the differentiation of myxomas from myxoid sarcomas. Classification performance did not improve when incorporating qualitative features or multiparametric imaging data.

PLAIN LANGUAGE SUMMARY

Accurately distinguishing between benign soft tissue myxomas and malignant myxoid sarcomas is essential for guiding appropriate management but remains challenging with conventional MRI interpretation. This study utilized radiomics, a method that extracts quantitative mathematically derived features from images, to develop predictive models based on routine MRI examination. Analyzing over 500 cases, MRI radiomics demonstrated excellent diagnostic accuracy in differentiating between benign myxomas and malignant myxoid sarcomas, highlighting the potential of the technique, as a powerful non-invasive tool that could complement current diagnostic approaches, and enhance clinical decision-making in patients with soft tissue myxoid tumors of the musculoskeletal system.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Intramuscular myxoma: unusual observation of spontaneous tumor size shrinkage

Soft tissue tumors, whether benign or malignant, may grow over time or remain stable, but they usually do not spontaneously decrease in size. However, there are exceptions, such as inflammatory conditions, desmoid tumors, or benign cysts. Intramuscular myxomas are benign soft tissue tumors that typically present as a solitary, slow-growing, painless mass. They are generally treated by surgical resection, after which recurrence is rare. Here, we present a brief series of three unusual cases of intramuscular myxomas that spontaneously decreased in size. They were located in the cervical region, the right lower extremity, and the paravertebral lumbar region. Imaging findings and percutaneous biopsies confirmed the diagnosis in all cases. Follow-up imaging showed a spontaneous reduction in lesion volume over time, far exceeding the amount of tissue sample removed during biopsy. This unusual observation of spontaneous shrinkage may call into question the subsequent therapeutic approach to these lesions.

Magnetic resonance imaging assessing the correlation of components and prognosis in myxoid liposarcoma

BackgroundMyxoid liposarcoma (MLS) is a subtype of liposarcoma characterized by its myxoid stroma and adipocyte differentiation. MLS is prone to recurrence and metastasis. Magnetic resonance imaging (MRI) plays a crucial role in evaluating tumor characteristics, enabling accurate diagnosis, and predicting patient prognosis.PurposeTo analyze the components of MLS by MRI features and assess their correlation with prognosis.Material and MethodsA total of 20 patients with MLS who underwent MRI were retrospectively included. Tumor components were analyzed by MRI features, and their prognostic correlation was assessed. Patients were divided into good and poor prognosis groups based on postoperative follow-up.ResultsThe proportions of non-fatty/non-myxoid components in the good and poor prognosis groups were 15.00% (range = 10.00%-20.00%) and 70.00% (range = 52.50%-77.50%), respectively (P < 0.001). The proportion of myxoid composition also differed significantly between the two groups (75.00%, [range = 65.00%-85.00%] vs. 25.00% [range = 17.50%-42.50%]; P < 0.001). The good prognosis group had a greater mean apparent diffusion coefficient (ADC) value (1.66 ± 0.23 × 10-3 mm2/s) and a lower mean ADC low signal ratio (5.00% [range = 0%-10.00%]) in the non-fatty/non-myxoid areas than the poor group (1.21 ± 0.41 × 10-3 mm2/s; 20.00% [range = 11.00%-39.00%]; P = 0.006 and P = 0.001). The differences in the percentages of patients with a component ratio <25% and >50% in both the non-fatty/non-myxoid and myxoid groups were significant (P < 0.001 and P = 0.005).ConclusionImaging features were closely associated with the histological components of MLS. The use of MRI features for assessing MLS components has important implications for prognostic prediction.

Exact radiological-pathological correlation of chondrosarcomas using a patient-specific 3D mold

OBJECTIVE

To identify aggressive regions in high-grade and dedifferentiated chondrosarcomas on MRI by obtaining an exact correlation between radiology and histopathology.

MATERIALS AND METHODS

One chondrosarcoma grade II (CSII), chondrosarcoma grade III (CSIII) and dedifferentiated chondrosarcoma (DDCS) were segmented on (DCE-)MRI images. Around the segmentations, a patient specific mold was constructed and 3D-printed with cutting grooves perfectly aligned with selected MRI slices. In this way, resection specimens could be cut at the same locations as the MRI slices. Histopathology slides were stained with hematoxylin-eosin and CD31 (vascularization) and correlated with the (DCE-)MRI. Histopathologically, atypical cartilaginous tumor (ACT), CSII, CSIII and DDCS regions were delineated and vascular hotspots were selected by an experienced pathologist. Exact point-to-point correlation was performed.

RESULTS

ACT, CSII, CSIII and DDCS regions all had similar mean signal intensity on T1-weighted images. On fat-saturated T2-weigthed images, CSII and CSIII regions had a higher mean signal intensity. On fat-saturated T1-weighted images after gadolinium contrast injection and on wash-in parametric maps DDCS regions had the highest mean signal intensity and highest wash-in values. There was a higher microvessel density in CSII and CSIII regions. This corresponded with a thick enhancing rim on fat-saturated T1-weighted images after gadolinium contrast injection and with a higher wash-in.

CONCLUSION

This new 3D mold helps to identify high-grade chondrosarcoma regions with myxoid. This may be useful for targeted biopsy and histopathological investigation.

Unveiling the swirl sign: A radiologic-pathologic correlation in deep angiomyxoma

Deep angiomyxoma (DA) is a rare, slow-growing soft tissue tumor typically affecting women of reproductive age. Despite its benign histology, it poses significant clinical challenges due to local invasiveness and high recurrence. Accurate diagnosis through radiologic imaging, particularly MRI, is essential for guiding treatment. One key imaging feature of DA is the "swirl sign," a distinctive pattern on T2-weighted images. However, its histological basis remains unclear. Here, we present a case of DA in a 46-year-old woman, highlighting the correlation between radiologic and histopathologic findings. MRI showed the characteristic swirl sign, which histologically corresponded to straight-running blood vessels aligned with the tumor's long axis, supported by collagen fibers within an edematous stroma. This case offers novel insight into the origins of the swirl sign and provides research questions on this sign. Further research is needed to explore its potential as a biomarker for tumor growth and aggressiveness.

Clinician's primer for soft tissue sarcomas: Nuances of histologic subtypes

Soft tissue sarcomas are a rare group of mesenchymal malignancies, with greater than 100 histologic subtypes. Advancements in understanding these subtypes has enabled histology-tailored management. This primer describes the workup and management of generalized soft tissue sarcomas of the extremity, trunk, and retroperitoneum while also highlighting the unique attributes of many subtypes. The subtypes chosen for review include those that are most common as well as those demonstrating unique behaviors or targets for management. The focus is on initial management of localized disease; however, for situations in which novel systemic agents have been discovered, the treatment of metastatic disease is discussed. This report is a reference to be used in addition to other comprehensive reviews, such as guidelines from the National Comprehensive Cancer Network, the European Society for Medical Oncology, and the American Society for Radiation Oncology. It is not a substitute for referral to an expert sarcoma center for critical pathology review and management by an experienced team. Importantly, patients who are treated at expert sarcoma centers have better outcomes than those who are not.

What Is the Prevalence and Fate of Myxoid Soft-Tissue Tumors With an Indeterminate Diagnosis Prior to Resection?

INTRODUCTION

Differentiating benign and malignant myxoid soft-tissue tumors preoperatively can be challenging due to shared clinical, imaging, and histologic features. Biopsy specimens are frequently described as "low-grade myxoid neoplasms" without benign or malignant classification (ie, indeterminate). Our purpose is to evaluate the prevalence and prognosis of myxoid tumors with an indeterminate diagnosis before resection.

METHODS

A retrospective review identified 439 patients with a musculoskeletal myxoid soft-tissue tumor confirmed on final resection pathology. Biopsy result (benign, malignant, indeterminate) for each biopsy type was compared with the final resection diagnosis. Indeterminate diagnosis before resection was defined as when the preoperative diagnosis was uncertain to be benign or malignant based on all biopsy data. For patients with sarcomas on final resection and 2-year follow-up, the prevalence of positive margins and local recurrence were compared between patients with an indeterminate diagnosis before resection and those with a malignant diagnosis known preoperatively.

RESULTS

The prevalence of indeterminate diagnosis before resection was 28% (66/235). In these patients with sarcomas on final resection and 2-year follow-up, the positive margin rate at resection surgery was 37% (10/27) compared with 15% (11/74) in patients with a malignant diagnosis known preoperatively (P = 0.049). Their 5-year local recurrence-free survival was 73% (95% confidence interval, 58 to 92) compared with 92% (95% confidence interval, 86 to 98) in patients with a malignant diagnosis known preoperatively (P = 0.022).

CONCLUSION

Indeterminate diagnosis before resection in myxoid tumors is relatively common, compared with prior reports in nonmyxoid neoplasms. Patients with indeterminate diagnosis before resection had two times higher rate of positive margins at resection surgery and markedly shorter local recurrence-free survival at 5 years compared with patients with malignant diagnosis known preoperatively. Diagnostic uncertainty at the time of resection is associated with worse oncologic outcomes in myxoid tumors.

Distinguishing benign and malignant myxoid soft tissue tumors: Performance of radiomics vs. radiologists

INTRODUCTION

Benign and malignant myxoid soft tissue tumors have shared clinical, imaging, and histologic features that can make diagnosis challenging. The purpose of this study is comparison of the diagnostic performance of a radiomic based machine learning (ML) model to musculoskeletal radiologists.

METHODS

Manual segmentation of 90 myxoid soft tissue tumors (45 myxomas and 45 myxofibrosarcomas) was performed on axial T1, and T2FS or STIR magnetic resonance imaging sequences. Eighty-seven radiomic features from each modality were extracted. Five ML models were trained to classify tumors as benign or malignant in 40 tumors and then tested with an additional 50 tumors using cross validation. The accuracy of the best ML model based on area under the receiver operating characteristic curve (AUC) was compared to the consensus diagnosis of three musculoskeletal radiologists. Correlation between radiologist confidence (equivocal, probably, consistent with) and accuracy was tested.

RESULTS

The best ML classifier was a logistic regression model (AUC 0.792). Using T1 + T2/STIR images, the ML model classified 78% (39/50) of tumors correctly at a similar rate compared to 74% (37/50) by radiologists. When radiologists disagreed, the consensus diagnosis classified 50% of tumors (7/14) correctly compared to 86% (12/14) by the ML model, though this did not reach statistical significance. Radiologists had a cumulative accuracy of 91% (30/33) when they rated their confidence 'consistent with' compared to 61% (31/51) when they rated their confidence 'equivocal/probably' (P = 0.006). For cases when radiologists rated their confidence 'equivocal/probably', the ML model had 76% accuracy (39/51).

CONCLUSIONS

A radiomic based ML model predicted benign or malignant diagnosis in myxoid soft tissue tumors similarly to the consensus diagnosis by three musculoskeletal radiologists. Radiologist confidence in the diagnosis strongly correlated with their diagnostic accuracy. Though radiomics and radiologists perform similarly overall, radiomics may provide novel diagnostic utility when radiologist confidence is low, or when radiologists disagree.

Myxoma: An Unusual Aggressive Orbital Lesion

Myxoma is a rare tumor that can be challenging to diagnose, with imaging findings that can be nonspecific. We present a case of a 21-year-old man who presented with a subacute history of right visual deterioration and proptosis. Imaging showed a large right superomedial orbital mass of 43 × 31 × 24 mm, which enhanced heterogeneously and was eroding the adjacent orbital roof and medial wall. An excisional biopsy was performed via a lid crease approach under transorbital endoscopic guidance. We review the clinical, radiological, and histological characteristics of myxoma. In addition, we highlight important associations with genetic syndromes including Carney complex and Mazabraud syndrome.

Imaging of MSK infections in the ER

Musculoskeletal infections in the ER are not an uncommon presentation. The clinical context is critical in determining the suspicion for infection and degree of tissue involvement which can involve all layers from the skin to bones. The location, extent, and severity of clinically suspected infection directly relate to the type of imaging performed. Uncomplicated cellulitis typically does not require any imaging. Localized and superficial infections can mostly be evaluated with ultrasound. If there is a diffuse site (an entire extremity) or suspected deeper involvement (muscle/deep fascia), then CT is accurate in diagnosing, widely available, and performed quickly. With potential osseous involvement, MRI is the gold standard for diagnosing acute osteomyelitis; however, it has the drawbacks of longer scan times, artifacts including patient motion, and limited availability.

Soft tissue myxoma manifesting as a slowly growing subcutaneous mass in the anterior chest wall: A case report

Soft tissue myxomas are benign mesenchymal neoplasms typically found in the intramuscular components of the proximal extremities. However, soft tissue myxomas in the chest wall are rare. We report the case of a 41-year-old woman with soft tissue myxoma who presented with a slowly growing, palpable lump on her left anterior chest wall that has been present for several years. Mammography revealed an oval, circumscribed, and hyperdense mass in the retromammary fat layer of the upper inner quadrant of the left breast. Ultrasonography revealed an oval, circumscribed, and hypoechoic mass with internal echoes and multiple microcystic spaces. A triangular hyperechoic area adjacent to the pole of the mass and peripheral hyperechoic rim were also detected. The patient underwent surgical excision and was diagnosed with soft tissue myxoma with subcutaneous manifestation.

Detecting residual soft tissue sarcoma after unplanned excision; model-free analysis of dynamic contrast-enhanced MRI at short-term follow-up

OBJECTIVES

To evaluate diagnostic utility of additional DCE-MRI for detecting residual soft tissue sarcomas (STS) after unplanned excision (UPE).

METHODS

We retrospectively evaluated 32 patients with UPE of STS, followed by conventional MRI with DCE-MRI and wide excision (WE), between November 2019 and January 2022. Residual tumors on conventional MRI were categorized into three groups: Lesion-type-0, no abnormal enhancement, Lesion-type-1, an indeterminate lesion, and Lesion-type-2, a definite enhancing nodule. On DCE-MRI, ROIs were manually placed on enhancing areas of suspected residual tumor. The mean and 95th percentile values of AUC of time-intensity curve were calculated at 60, 90, and 120 s of Enhancement-cycle-1 and -2. Optimal DCE parameters were identified by ROC analysis. Diagnostic performance of conventional MRI and DCE-MRI was compared using McNemar's test.

RESULTS

On WE, residual tumor was present in 23 (71.9%) of 32 patients. On MRI, Lesion-type-1 was found in 16/32 (50%) patients and Lesion-type-2 in 16/32 (50%). The optimal DCE parameter was the 95th percentile value of AUC at 120s of Enhancement-cycle-2. The sensitivity, specificity, and AUC were as follows: 65.2% (95% CI, 45.8-85.7%), 88.9% (CI, 68.4-100%), and 0.77 (CI, 0.62-0.92) for conventional MRI, and 100%, 55.6% (CI, 23.1-88.0%), and 0.78 (CI, 0.61-0.95) for combined conventional and DCE-MRI.

CONCLUSIONS

Additional DCE-MRI aided in detecting residual STS after UPE, particularly in cases without definite soft tissue nodular enhancement.

ADVANCES IN KNOWLEDGE

Close follow up may be suggested for patients showing abnormality in DCE-MRI, with more suspicion of residual tumor.

[Contribution of whole-body MRI to the initial assessment of myxoid liposarcoma]

INTRODUCTION

Myxoid liposarcoma is a soft tissue sarcoma associated with multifocal metastases at diagnosis. These metastases are asymptomatic and occult on CT and FDG-PET and can alter the therapeutic management and prognosis. In this context, we evaluated the contribution of whole-body MRI to the initial workup of patients with myxoid liposarcoma.

METHOD

This retrospective study was conducted between January 2015 and December 2020 at the Oscar Lambret Center. We enrolled 22 patients who were diagnosed with myxoid liposarcoma and underwent whole-body MRI at diagnosis. The number of metastases at diagnosis, their location, and the visibility of these lesions on CT were evaluated. Associations between clinical features, presence of metastasis, and their impact on management were assessed.

RESULTS

Sixteen patients (72.7%) had non-metastatic disease at the initial diagnosis, and 15 of these patients were managed using local treatment. Six patients (27.3%) had metastases at multiple locations and received chemotherapy. The main locations were the bones (n=5) and lungs (n=3). In five patients with metastases, whole-body MRI demonstrated additional lesions that were not visible on CT (bone and soft tissue lesions). Only the presence of a round cell contingent (P=0.009) was found as a criterion associated with the presence of metastases.

CONCLUSION

The patients' young age, absence of reliable prognostic factors at diagnosis, asymptomatic nature of the lesions, and the benefits of early and targeted therapeutic management encourage the use of whole-body MRI as part of the initial work-up as it seems to provide a better initial staging compared with conventional imaging.

Diagnostic conundrums of schwannomas: two cases highlighting morphological extremes and diagnostic challenges in biopsy specimens of soft tissue tumors

Schwannomas are benign, slow-growing peripheral nerve sheath tumors commonly occurring in the head, neck, and flexor regions of the extremities. Although most schwannomas are easily diagnosable, their variable morphology can occasionally create difficulty in diagnosis. Reporting pathologists should be aware that schwannomas can exhibit a broad spectrum of morphological patterns. Clinical and radiological examinations can show correlation and should be performed, in conjunction with ancillary tests, when appropriate. Furthermore, deferring a definitive diagnosis until excision may be necessary for small biopsy specimens and frozen sections. This report underscores these challenges through examination of two unique schwannoma cases, one predominantly cellular and the other myxoid, both of which posed significant challenges in histological interpretation.

The T2-FLAIR mismatch sign as an imaging biomarker for oligodendrogliomas in dogs

BACKGROUND

In humans, the T2-weighted (T2W)-fluid-attenuated inversion recovery (FLAIR) mismatch sign (T2FMM) is a specific imaging biomarker for the isocitrate dehydrogenase 1 (IDH1)-mutated, 1p/19q non-codeleted low-grade astrocytomas (LGA). The T2FMM is characterized by a homogeneous hyperintense T2W signal and a hypointense signal with a hyperintense peripheral rim on FLAIR sequences. In gliomas in dogs, the T2FMM has not been described.

HYPOTHESES/OBJECTIVES

In dogs with focal intra-axial brain lesions, T2FMM will discriminate gliomas from other lesions. The T2FMM will be associated with the LGA phenotype and presence of microcysts on histopathology. Interobserver agreement for T2FMM magnetic resonance imaging (MRI) features will be high.

ANIMALS

One hundred eighty-six dogs with histopathologically diagnosed focal intra-axial lesions on brain MRI including oligodendrogliomas (n = 90), astrocytomas (n = 47), undefined gliomas (n = 9), cerebrovascular accidents (n = 33), and inflammatory lesions (n = 7).

METHODS

Two blinded raters evaluated the 186 MRI studies and identified cases with the T2FMM. Histopathologic and immunohistochemical slides of T2FMM cases were evaluated for morphologic features and IDH1-mutations and compared to cases without the T2FMM. Gene expression analyses were performed on a subset of oligodendrogliomas (n = 10) with and without T2FMM.

RESULTS

The T2FMM was identified in 14/186 (8%) of MRI studies, and all dogs with T2FMM had oligodendrogliomas (n = 12 low-grade [LGO], n = 2 high-grade [HGO]; P < .001). Microcystic change was significantly associated with the T2FMM (P < .00001). In oligodendrogliomas with T2FMM, IDH1-mutations or specific differentially expressed genes were not identified.

CONCLUSION AND CLINICAL IMPORTANCE

The T2FMM can be readily identified on routinely obtained MRI sequences. It is a specific biomarker for oligodendroglioma in dogs, and was significantly associated with non-enhancing LGO.

A tale of two vulvar angiomyxomas: Two cases and review of literature

Vulvar angiomyxomas are rare benign mesenchymal neoplasms. Superficial and Aggressive angiomyxomas are two distinct phenotypes that present similarly to other more common vulva-perineal pathologies. Albeit both angiomyxomas carry a risk of recurrence, especially in the setting of incomplete resection, simple excision is insufficient for Aggressive angiomyxoma. It requires wide local excision because of its unique potential for local invasion, infiltration of the paravaginal and pararectal tissue, and more distant metastasis. Here, we present a case of Superficial angiomyxoma and a case of Aggressive angiomyxoma to highlight the diagnostic challenges and management strategies of each tumor. In both cases, angiomyxomas were initially misdiagnosed because of their rarity and nonspecific presentation. Magnetic resonance imaging is the modality of choice for evaluation due to inherent higher spatial resolution of soft tissue anatomical details. Early diagnosis of Aggressive angiomyxoma can prevent incomplete excision and recurrence, spare additional surgery, and offer hormonal therapy options.

Myxomas and myxoid liposarcomas of the extremities: Our preliminary findings in conventional, perfusion, and diffusion magnetic resonance

Background

The differentiation between myxomas and myxoid liposarcomas (MLPS) often is a serious challenge for the radiologists. Magnetic resonance imaging (MRI) is the most useful imaging technique in characterization of the soft tissue tumors (STT).

Purpose

To evaluate in a sample of myxomas and MLPS of the extremities, what morphological findings in conventional MRI allow us to differentiate these two types of myxoid tumors, in addition to analyzing the validity of the apparent diffusion coefficient (ADC) values of diffusion-weighted MRI (DW-MRI).

Material and Methods

Magnetic resonance imaging studies in myxomas and MLPS of extremities searched in our PACS between 2015 and 2019. All studies had conventional MRI with T1, T2, and PD SPAIR sequences, while DW-MRI with ADC mapping and perfusion MRI with a T1 sequence repeated for 4 minutes after contrast injection were additional sequences only in some explorations. Two radiologists evaluated independently the MRI studies by examining the qualitative parameters. Apparent diffusion coefficient values were calculated using two methods-ADC global and ADC solid, and Receiver Operating Characteristic (ROC) curves were applied for analysis.

Results

The features were consistent with MLPS: size greater than 10 cm, heterogeneous signal on T1, and nodular enhancement, while the common findings for myxomas were a homogenously hypointense signal on T1 and diffuse peritumoral enhancement. The solid and global ADC values were higher in myxomas. We observed that the solid ADC value less than 2.06 x 10^-3mm² x s would support the diagnosis of MLPS against myxoma.

Conclusion

Overall, MRI with its different modalities improved the diagnostic accuracy when differentiating myxomas from MLPS of extremities.

Myxoid liposarcoma originating in the retroperitoneum with metastasis to the calcaneus: a rare case report and review of literature

Myxoid liposarcoma (MLPS) is known to have a variety of metastatic manifestations. We report a MLPS originating in the pelvis with metastasis to the calcaneus. The patient was a 72-year-old man who developed lumbar pain and right lower extremity pain 2 years ago. He visited a nearby clinic and underwent a radiographic examination. Computed tomography (CT) revealed a tumor in the right retroperitoneum. A CT-guided needle biopsy was performed, and pathological examination revealed myxoid liposarcoma. Wide surgical resection was not performed due to the patients' wishes, technical difficulties, and magnitude of the invasion, and the patient received heavy particle radiation therapy (HPRT) of 70.4 Gy. After HPRT, the tumor mass was slightly reduced. However, 11 months after HPRT, a recurrent lesion in the liver was observed. Although HPRT was performed again for the metastatic liver lesion (70.4 Gy), the tumor increased in size. Furthermore, 1 month later, the patient complained of pain in the left foot, and CT and magnetic resonance imaging revealed an osteolytic lesion in the calcaneus. A biopsy was performed, and pathological examination showed a metastatic lesion of myxoid-type liposarcoma. The patient wore a short lower limb orthosis and was able to walk but died 1 month later. Oncologists should note that MLPS can metastasize to the calcaneus.

Myxolipoma of hand in a child: case report of a rare tumor

Lipomatous tumors account for less than 10% of tumors in the pediatric population. Myxolipomas (a subset of lipoma characterised by mature adipose tissue and abundant mucoid substance) are found to be even rarer. There are a few case reports in different body parts like heart, kidney, oral cavity, epiglottis, cervical and mediastinal regions. However, there are no case reports on the involvement of the hands in any age group. High resolution ultrasound is the imaging modality of choice for the initial evaluation of superficial soft tissue tumors, their site, nature and extent. In conjunction with clinical findings and age of presentation, it helps in narrowing down the differential diagnosis and planning the management. Hyperechoic fatty tumors in the pediatric hand are mostly benign and includes lipomas, lipoblastomas and fibrous hamartomas of infancy as the main differentials. A definitive diagnosis is based on a histo-pathological and molecular cytogenetic examination. This article presents a never before reported case of a rare, large, myxolipoma of the hand in a 22-month-old boy.

Case Report: Inguinal Myxofibrosarcoma Arising From the Surgical Site of Resected Squamous Cell Carcinoma

Myxofibrosarcoma (MFS) is a rare soft tissue sarcoma that originates in the mesenchymal tissue and occurs mainly in the limbs of elderly patients. Herein, we present the case of a 64-year-old woman who underwent extensive left vulvar resection and bilateral lymphadenectomy for vulvar squamous cell carcinoma 6 months previously. A mass was found again at the original surgical site of the left groin 3 months prior, and its size had increased significantly in the past 1 month, with ulceration and pus. Magnetic resonance imaging (MRI) showed a 10-cm mass in the left groin area; fluoro18-labeled deoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) showed a marked increase in mass metabolism in the left groin area, which was highly suspected to be a recurrence of squamous cell carcinoma. Subsequently, the patient underwent surgery and the postoperative pathology and immunohistochemistry confirmed MFS. In conclusion, MFS has rarely been reported to arise from the surgical site of squamous cell carcinoma. Our case study demonstrates that MFS should be included in the differential diagnosis of superficial masses in patients with a prior surgical history who present with a soft tissue mass at the surgical site, especially for recently developed rapidly increasing masses. This study aimed to systematically review the clinical features, diagnosis, differential diagnosis, treatment, and prognosis of this disease based on our case and related published literature and to provide clinicians with a broader perspective on the differential diagnosis of soft tissue tumors.

Myxoinflammatory Fibroblastic Sarcoma of the Parotid Gland: First Case Report and Literature Review

Myxoinflammatory fibroblastic sarcoma (MIFS) is a rare, low-grade malignant soft tissue tumor. Most of the previously reported cases about this tumor were diagnosed within the soft tissues. Here, we report a unique case of MIFS of the right parotid gland in a 39-year-old Chinese male. The tumor primarily consisted of an inflammatory area and a mucus-like area in a migratory distribution. A number of lymphocytes, neutrophils, viral-like cells with large nucleoli, and eosinophilic cytoplasm or Reed-Sternberg-like cells, as well as spindle cells and epithelial-like aberrant cells, were observed within the tumor. They were found to express Vimentin and CD10 protein and no other specific immunohistochemical markers. The various cytomorphology and immunohistochemical features of this tumor were highly consistent with MIFS found in other sites. Therefore, several leading pathologists ultimately confirmed the final diagnosis of MIFS in the right parotid gland after repeated deliberation. To our knowledge, this is the first case of MIFS occurring in the parotid gland. Thus, our study provides a novel basis for identifying the biological behavior of the tumor in MIFS and also allows us to better understand the pathology of this rare tumor.

MRI imaging of soft tissues tumours and tumour like lesions-SLAM approach

Imaging is vital in characterising and delineating the extent of soft tissue tumours and there is abundant literature on this. A simplified approach is required to characterise the lesions on MR and we describe a simplified street-smart approach called SLAM (signal, location, age, multiplicity and matrix).

When is a lipoma not a lipoma? Case report presenting a lipoblastoma-like tumor of the gluteal cleft in an older gentleman with literature review

Introduction and importance

Lipoblastoma-like tumors are rare tumors that can be confused with lipoblastomas and liposarcomas but have distinct characteristics. This tumor has previously been identified in the vulva of females, and recently in isolated cases of young males. Given its rarity, we present an instance of this tumor in an older man, demonstrating that this pathology is not limited to a specific age or sex, and surgeons and pathologists must be aware of it in their differential.

Case presentation

A 58-year-old male presented for evaluation of an enlarging mass in his right gluteal cleft. Prior to referral for surgical evaluation, the patient underwent an ultrasound-guided biopsy of the mass. Histologically, the tumor was a low-grade cellular spindle cell neoplasm in a fibrous to myxoid stroma. Immunohistochemical and molecular workup ruled out several malignant mesenchymal neoplasms, including myxoid liposarcoma, dedifferentiated liposarcoma, melanoma, low-grade fibromyxoid sarcoma, and sarcomatoid carcinoma. The patient initially declined surgery, but the mass continued to grow, and excision was chosen given the uncertain pathology. The tumor was resected with negative margins and histologically characterized as a “lipoblastoma-like lesion”, with features of a myxoid liposarcoma and spindle cell lipoma. Seven months post-resection, there were no signs of recurrence or metastasis.

Clinical discussion

Despite radiologic and pathologic similarities to malignant lipomatous tumors, lipoblastoma-like tumors are benign and have a good prognosis.

Conclusions

Clinicians should be aware of this entity despite its rarity as resection with negative margins is curative and may be needed to rule out more aggressive tumors.

•

Lipoblastoma-like tumors (LLTs) are rare soft tissue tumors.

•

LLTs can easily be confused clinically and pathologically for benign lipomas but also malignant liposarcomas.

•

Pathologic evaluation is able to distinguish these tumors from their more aggressive counterparts.

•

Because of their rare nature, clinicians may over or under-treat these tumors which require surgical excision.

•

Local recurrence is rare but is predicated on negative surgical margins.

The Extracellular Matrix in Soft Tissue Sarcomas: Pathobiology and Cellular Signalling

Soft tissue sarcomas are rare cancers of mesenchymal origin or differentiation comprising over 70 different histological subtypes. Due to their mesenchymal differentiation, sarcomas are thought to produce and deposit large quantities of extracellular matrix (ECM) components. Interactions between ECM ligands and their corresponding adhesion receptors such as the integrins and the discoidin domain receptors play key roles in driving many fundamental oncogenic processes including uncontrolled proliferation, cellular invasion and altered metabolism. In this review, we focus on emerging studies that describe the key ECM components commonly found in soft tissue sarcomas and discuss preclinical and clinical evidence outlining the important role that these proteins and their cognate adhesion receptors play in sarcomagenesis. We conclude by providing a perspective on the need for more comprehensive in-depth analyses of both the ECM and adhesion receptor biology in multiple histological subtypes in order to identify new drug targets and prognostic biomarkers for this group of rare diseases of unmet need.

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

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

Magnetic resonance imaging of trunk and extremity myxoid liposarcoma: diagnosis, staging, and response to treatment

Myxoid liposarcoma (MLS) accounts for approximately 30% of all liposarcomas. The majority are intermediate-grade tumours, but the presence of >5% round cell component renders it a high-grade sarcoma with subsequent poorer outcome. MLS most commonly arises in the lower extremities, has a predilection for extra-pulmonary sites of metastatic disease, and is recognized to be radiosensitive. The purpose of the current article is to review the role of MRI in the management of MLS, including the characteristic features of the primary tumour, features which help to identify a round cell component and thus determine prognosis, the role of whole-body MRI for evaluation of extra-pulmonary metastatic disease, and the utility of MRI for assessing treatment response. The MRI differential diagnosis of MLS is also considered.

Surgery Treatment Improved the Overall Survival Rate in Locoregional Myxoid Leiomyosarcoma than Other Myxosarcomas in the United States

Myxosarcomas are rare malignant tumors of soft connective tissues, classified into various subtypes, including myxoid liposarcoma, myxoid chondrosarcoma, and myxoid leiomyosarcoma. In this study, we proposed to study the demographic, tumor characteristics, and overall survival rate and compared the treatment modalities between these cancers. Patient data collected based on locoregional metastasis presentation of the abovementioned tumors with a cutoff study of survival duration up to 10 years were obtained from the SEER database during 1975-2016. Our results indicated that elderly patients and females were more in locoregional myxoid leiomyosarcoma than myxoid liposarcoma and myxoid chondrosarcoma with locoregional metastasis. The white race represented the most patients who suffered from these cancers than other races. The heart is the primary site for the abovementioned cancers, in addition to the female genitals to the myxoid leiomyosarcoma. Myxoid liposarcoma and myxoid chondrosarcoma patients with locoregional metastasis were suffering from grade II, while locoregional myxoid leiomyosarcoma patients with blank grading were due to missed data. Surgery was the most common treatment modality in this study compared with radiotherapy and chemotherapy. Kaplan-Meier analysis showed a significant difference in survival time between the three subtypes by using histology, and myxoid leiomyosarcoma showed prolonged survival than others. Elderly, female, white, unknown grade, surgery, no radiation, and no chemotherapy variables were independent factors associated with overall survival among these cancers. Multivariate analysis also showed significant differences in overall survival between the three tumors by histology, and myxoid leiomyosarcoma was with a better prognosis than others. Multivariate analysis of locoregional myxoid leiomyosarcoma showed the statistical significance of black race, grade, and radiotherapy, indicating them as independent prognostic factors of locoregional myxoid leiomyosarcoma. We conclude that surgery was the primary treatment modality against these cancers than radiotherapy and chemotherapy. And the locoregional myxoid leiomyosarcomas showed a better prognosis and higher survival rate than locoregional myxoid liposarcoma and locoregional myxoid chondrosarcoma.

Laryngeal myxoma: A case report

BACKGROUND

Myxomas are benign tumors of mesenchymal origin that rarely occur in the larynx.

CASE SUMMARY

We report a case of a laryngeal myxoma that presented as a right vocal cord mass in a 54-year-old man.

CONCLUSION

Laryngeal myxoma is a rare benign tumor in the larynx. It is difficult to distinguish glottis myxoma from vocal cord polyps on laryngoscopy. We recommend that otolaryngologists acquire a better understanding of this disease. If a laryngeal myxoma is suspected, dynamic laryngoscopy, acoustic voice analysis, and pathological biopsy should be performed.

Magnetic Resonance Imaging, the Virtual Biopsy of Mesenteric Masses

ABSTRACT

The mesentery may be affected by multiple disease processes. Magnetic resonance imaging aids as a virtual pathological biopsy tool in the assessment of mesenteric masses because of superior soft tissue contrast and characterization. In this comprehensive review, we describe in detail the magnetic resonance imaging features of some solid and cystic mesenteric masses, with an emphasis on lesion-specific signal characteristics on T1- and T2-weighted images, diffusion-weighted imaging, and enhancement features on the dynamic postcontrast phase that aid in narrowing the differential diagnosis.

Myxofibrosarcoma: Clinical and Prognostic Value of MRI Features

Myxofibrosarcoma is one of the most common soft tissue sarcomas in the elderly. It is characterized by an extremely high rate of local recurrence, higher than other soft tissue tumors, and a relatively low risk of distant metastases.Magnetic resonance imaging (MRI) is the imaging modality of choice for the assessment of myxofibrosarcoma, which plays a key role in the preoperative setting of these patients. MRI features associated with the high risk of local recurrence are: high myxoid matrix content (water-like appearance of the lesions), high grade of contrast enhancement and presence of an infiltrative pattern ("tail sign"). On the other hand, MRI features associated with worse sarcoma specific survival are: large size of the lesion, deep location, high grade of contrast enhancement. Recognizing the above-mentioned imaging features of myxofibrosarcoma may be helpful in stratifying the risk for local recurrence and disease-specific survival. Moreover, the surgical planning should be adjusted according to the MRI features.

Surgical Treatment of Intramuscular Myxoma

PURPOSE

Intramuscular myxoma (IM) is a rare benign myxoid tumor that may be challenging to differentiate from sarcoma in small amounts of biopsied material. Although IM appears to be well-circumscribed macroscopically, it infiltrates the adjacent edematous muscle microscopically. The recommended treatment is resection, but there is controversy with regard to the appropriate surgical margin. This study aimed to clarify which surgical procedure that should be applied when the preoperative diagnosis is IM and how to manage treatment if the postoperative diagnosis turns out to be a sarcoma.

METHODS

We retrospectively examined 55 IM patients treated from January 1982 to December 2014. Patient characteristics, tumor location, tumor size, radiograph, preoperative and postoperative pathological reports, surgical techniques, treatment outcome, and complications were reviewed. The patients were followed up on for at least 5 years. All patients were confirmed not to have Mazabraud syndrome.

RESULTS

In the 55 IM patients examined, the mean patient age was 48 years and most were female. The most common tumor locations were in the muscles of the thighs (47%) and buttocks (20%). The mean tumor diameter was 5 cm. Wide resection and marginal resection were performed in 24 and 31 patients, respectively. The mean follow-up duration was 19 years. No local recurrence, malignant transformation, or complications were observed.

CONCLUSIONS

Marginal resection is suitable in patients whose preoperative diagnosis is IM, as it is able to prevent local recurrence and allows for the preservation of muscle and muscle fascia. If the postoperative diagnosis turns out to be myxoid sarcoma, minimum surgical contamination makes additional wide resection less invasive.

Imaging spectrum of mesenteric masses

Mesenteries are extensions of the visceral and parietal peritoneum consisting of fat, vessels, nerves, and lymphatics. Mesenteric masses have a wide differential diagnosis with neoplastic, infectious, or inflammatory etiologies and can either be solid or cystic. Imaging features are critical for the diagnosis. We review the epidemiology, imaging spectrum, and differentiating features and treatment of mesenteric masses.

Multiparametric quantitative analysis of tumor perfusion and diffusion with 3T MRI: differentiation between benign and malignant soft tissue tumors

OBJECTIVE

To evaluate multiparametric MRI for differentiating benign and malignant soft tissue tumors.

METHODS

This retrospective study included 67 patients (mean age, 55 years; 18-82 years) with 35 benign and 32 malignant soft tissue tumors. Intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI)-derived parameters (D, D*, f), apparent diffusion coefficient (ADC), and dynamic contrast-enhanced (DCE)-MRI parameters (K^trans, K_ep, V_e, iAUC) were calculated. Myxoid and non-myxoid soft tissue tumors were divided for subgroup analysis. The parameters were compared between benign and malignant tumors.

RESULTS

ADC and D were significantly lower in malignant than benign soft tissue tumors (1170 ± 488 vs 1472 ± 349 µm²/s; 1132 ± 500 vs 1415 ± 374 µm²/s; p < 0.05). K^trans, K_ep, V_e, and iAUC were significantly different between malignant and benign soft tissue tumors (0.209 ± 0.160 vs 0.092 ± 0.067 min^-1; 0.737 ± 0.488 vs 0.311 ± 0.230 min^-1; 0.32 ± 0.17 vs 0.44 ± 0.28; 0.23 ± 0.14 vs 0.12 ± 0.09, p < 0.05, respectively). ADC (0.752), D (0.742), and K_ep (0.817) had high AUCs. Subgroup analysis showed that only K^trans, and iAUC were significantly different in myxoid tumors, while, ADC, D, K^trans, K_ep, and iAUC were significantly different in non-myxoid tumor for differentiating benign and malignant tumors. D, K_ep, and iAUC were the most significant parameters predicting malignant soft tissue tumors.

CONCLUSION

Multiparametric MRI can be useful to differentiate benign and malignant soft tissue tumors using IVIM-DWI and DCE-MRI.

ADVANCES IN KNOWLEDGE

1. Pure tissue diffusion (D), transfer constant (K^trans), rate constant (K_ep), and initial area under time-signal intensity curve (iAUC) can be used to differentiate benign malignant soft tissue tumors.2. K^trans and iAUC enable differentiation of benign and malignant myxoid soft tissue tumors.

Myxoid Liposarcoma With Skeletal Metastases: Pathophysiology and Imaging Characteristics

Liposarcoma is a commonly occurring soft tissue sarcoma that can be divided into 4 subtypes. Myxoid and round cell liposarcoma (MRCL) represent one of these subtypes and are classified together due to their shared chromosomal translocation. Histologic analysis of MRCL reveals a myxoid matrix with a delicate capillary network and dispersed lipoblasts. Varying degrees of round cell component are also observed, with greater amounts of round cells indicating a higher histologic grade and poorer prognosis. MRCL has a unique pattern of spread due to its initial tendency to spread to extrapulmonary sites. Additionally, skeletal metastases are frequently found in cases of MRCL. While various imaging techniques are used to visualize MRCL and metastases, magnetic resonance imaging is generally the preferred method. This article reviews the pathophysiology and imaging features of MRCL as well as the imaging characteristics, advantages, and drawbacks of multiple imaging modalities for visualizing bone metastases.

Master knot of Henry revisited: a radiologist's perspective on MRI

The master knot of Henry refers to a narrow space located between the anatomical crossover of the flexor hallucis longus and flexor digitorum longus tendons. This small space is prone to "intersection syndrome," as a result of tendinosis, tenosynovitis, and tears of the aforementioned tendons at the knot of Henry. The aim of this educational review is to detail the anatomy of the knot of Henry, including common variations in the tendon position and orientation. These complex interconnections can affect the outcome of surgical intervention if not appreciated at the time of treatment. We will also provide an overview of the common and rarer pathologies related to the knot of Henry. The aim of the present review is to make radiologists more aware of pathologies in this region, which are not routinely seen in daily practice.

Ossifying fibromyxoid tumor: a rare case

Ossifying fibromyxoid tumour (OFMT) is a rarely occurring soft tissue neoplasm of mesenchymal origin. It is a rarely found tumour with intermediate behaviour and differentiation. Although it is mostly benign, malignant variants also exist. We are presenting a case of 32-year-old man presented in clinic with complaints of painless swelling in left distal thigh. After reviewing his X-ray, a diagnostic biopsy was planned which came out to be suspicious of solitary fibrous tumour. Other radiological workup was done and the patient was planned to undergo wide margin excision. The final histopathology showed a diagnosis of OFMT of soft tissue, atypical variant. The patient is under follow-up and is disease free. This type of tumour possesses potential of local recurrence and metastases; therefore, it is important to keep a long-term follow-up of patient.

[Myxoid soft tissue tumours : An algorithm for differential diagnosis]

Soft tissue neoplasms with myxoid features are collectively not uncommon. Their often complex differential diagnosis makes them significantly over-represented among consultation cases. This applies not only to sarcomas but in particular to benign lesions as well. Generally, myxoid soft tissue lesions are divided into two major groups: (1) myxoid lesions by definition (which can however rarely be non-myxoid) and (2) rare myxoid variants of otherwise non-myxoid entities.Four major diagnostic challenges are responsible for the complexity of myxoid soft tissue neoplasms: (1) Diagnosis of malignancy in many cases is not based on conventional malignancy criteria but is defined by the entity itself, making under-diagnosis of malignancy likely in entities such as low-grade fibromyxoid sarcoma. (2) On the other hand, harmless myxoid lesions with features of high proliferation, e.g. nodular and proliferative fasciitis, tend to be over-diagnosed as malignant by the unworried. (3) The necessity to assess not only cellular morphology/differentiation, but also the stromal, vascular and architectural characteristics adds to the complexity of the differential diagnostic algorithm. (4) Last but not least, recognition of unexpected myxoid variants of non-myxoid entities is basically impossible if focal conventional areas are absent, underlining the need for high suspicion index and sufficient sampling.This review illuminates the various aspects related to the differential diagnostic workup of these challenging entities.

Radiomic features from MRI distinguish myxomas from myxofibrosarcomas

BACKGROUND

Myxoid tumors pose diagnostic challenges for radiologists and pathologists. All myxoid tumors can be differentiated from each other using fluorescent in-situ hybridization (FISH) or immunohistochemical markers, except for myxomas and myxofibrosarcomas. Myxomas and myxofibrosarcomas are rare tumors. Myxomas are benign and histologically bland, whereas myxofibrosarcomas are malignant and histologically heterogenous. Because of the histological heterogeneity, low grade myxofibrosarcomas may be mistaken for myxomas on core needle biopsies. We evaluated the performance of T1-weighted signal intensity (T1SI), tumor volume, and radiomic features extracted from magnetic resonance imaging (MRI) to differentiate myxomas from myxofibrosarcomas.

METHODS

The MRIs of 56 patients (29 with myxomas, 27 with myxofibrosarcomas) were analyzed. We extracted 89 radiomic features. Random forests based classifiers using the T1SI, volume features, and radiomic features were used to differentiate myxomas from myxofibrosarcomas. The classifiers were validated using a leave-one-out cross-validation. The performances of the classifiers were then compared.

RESULTS

Myxomas had lower normalized T1SI than myxofibrosaromas (p = 0.006) and the AUC using the T1SI was 0.713. However, the classification model using radiomic features had an AUC of 0.885 (accuracy = 0.839, sensitivity = 0.852, specificity = 0.828), and outperformed the classification models using T1SI (AUC = 0.713) and tumor volume (AUC = 0.838). The classification model using radiomic features was significantly better than the classifier using T1SI values (p = 0.039).

CONCLUSIONS

Myxofibrosarcomas are on average higher in T1-weighted signal intensity than myxomas. Myxofibrosarcomas are larger and have shape differences compared to myxomas. Radiomic features performed best for differentiating myxomas from myxofibrosarcomas compared to T1-weighted signal intensity and tumor volume features.

18F-FDG PET/CT and MRI features of myxoid liposarcomas and intramuscular myxomas

OBJECTIVE

To examine the imaging characteristics of intramuscular myxomas (IM) and myxoid liposarcomas (MLS) on ¹⁸F-FDG PET/CT and MRI.

MATERIALS AND METHODS

With IRB approval, our institutional imaging database was searched for pathologically proven IM and MLS evaluated by ¹⁸F-FDG PET/CT and MRI. PET/CT and MRI imaging characteristics were recorded and correlated with pathologic diagnosis.

RESULTS

We found eight patients (2 M, 6 F) with IM (mean age 65.6 ± 10.4 years) and 16 patients (7 F, 9 M) with MLS (mean age 42.8 ± 16.3 years). MRI was available in 7/8 IM and 15/16 MLS patients. There was no significant difference between the two groups in SUVmax (IM 2.7 ± 0.8, MLS 3.0 ± 1.0; p = 0.35), SUVmean (1.7 ± 0.4, 1.5 ± 0.5; p = 0.40), total lesion glycolysis (101.8 ± 127.3, 2420.2 ± 4003.3 cm³*g/ml; p = 0.12), metabolic tumor volume (62.3 ± 71.1, 1742.9 ± 3308.0 cm³; p = 0.17) or CT attenuation (p = 0.70). MLS occurred in younger patients (p = 0.0015), were larger (16.4 ± 8.2 vs. 5.6 ± 2.5 cm; p = 0.0015), more often T1 hyperintense (p = 0.03), with nodular enhancement (p = 0.006), and macroscopic fat on CT (p = 0.0013) and MRI (p = < 0.001) compared to myxomas.

CONCLUSIONS

IM and MLS most commonly demonstrate low-grade FDG activity and overlapping metabolic measures on PET/CT. MRI is useful in differentiation, but MLS can present without macroscopic fat on MRI, underscoring the importance of radiologic-pathologic correlation for accurate diagnosis.

Quantification of fat content in lipid-rich myxoid liposarcomas with MRI: a single-center experience with survival analysis

OBJECTIVE

To determine the fat content of myxoid liposarcomas (MLS) on MRI and to identify any association between lipid content and survival.

MATERIALS AND METHODS

The fat percentage of MLS diagnosed between January 2006 and December 2016 at a single institution was assessed by two radiologists on preoperative MR images. A Cox proportional hazard model was used to determine any association between tumor fat percentage and survival time. Tumor fat percentage was the single predictor in the model. A significance level of 0.05 was used. The Kaplan-Meier estimator was also used to provide a nonparametric estimate of the survivor function within the entire sample and within two patient subgroups consists of lipid-rich and lipid-poor tumors. Lipid-rich tumors were defined as any tumors showing more than 20% of fat on MRI. A 20% cutoff was determined arbitrarily.

RESULTS

Of the 43 cases identified through retrospective review, 8 tumors demonstrated ≥10% fat on MRI, and 4 tumors demonstrated ≥20% fat (highest fat percentage, 38%). There was no significant survival difference between patients with high tumor fat, which was defined as ≥20% fat, compared with those with little to no tumor fat.

CONCLUSION

Myxoid liposarcomas may demonstrate a higher fat content on MRI than has previously been reported in the literature. Increased tumor fat percentage in lipid-rich tumors was not found to be associated with increased risk of death. Radiologists must be aware of the existence of MLS lesions with higher fat content.

Head and Neck Myxoma Presenting as Isolated Laryngeal Polyp

Myxoma is a benign tumour with a propensity for local infiltration and recurrence. Laryngeal myxoma presents as a submucosal polyp. Being an uncommon tumour and mimicking vocal cord polyp, only anecdotal evidence is available in the literature. The literature was reviewed from 1986 onwards using the keywords “myxoma” and “larynx.” The databases used were PubMed, Google Scholar, Scopus, and Web of Science. Along with this, we also report our case of vocal fold myxoma. We found a total of 19 studies reporting laryngeal myxoma. Laryngeal myxoma typically affects males in the 6th decade with a history of smoking. Unlike myxomas originating outside the larynx, recurrence is not widely described, and microlaryngeal surgery will usually suffice. Laryngeal myxomas should definitely be kept in the list of differential diagnosis when dealing with a benign-looking vocal fold lesion.

Imaging in Soft Tissue Sarcomas: Current Updates

Soft tissue sarcomas (STS) are heterogeneous malignant tumors that have nonspecific imaging features. A combination of clinical, demographic, and imaging characteristics can aid in the diagnosis. Imaging provides important information regarding the tumor extent, pretreatment planning, and surveillance of patients with STS. In this article, we illustrate the pertinent imaging characteristics of the commonly occurring STS and some uncommon sarcomas with unique imaging characteristics.