Recent advances in the management of liposarcoma

HER3 (ERBB3) amplification in liposarcoma - a putative new therapeutic target?

BACKGROUND

Liposarcomas are among the most common mesenchymal malignancies. However, the therapeutic options are still very limited and so far, targeted therapies had not yet been established. Immunotherapy, which has been a breakthrough in other oncological entities, seems to have no efficacy in liposarcoma. Complicating matters further, classification remains difficult due to the diversity of morphologies and nonspecific or absent markers in immunohistochemistry, leaving molecular pathology using FISH or sequencing as best options. Many liposarcomas harbor MDM2 gene amplifications. In close relation to the gene locus of MDM2, HER3 (ERBB3) gene is present and co-amplification could occur. Since the group of HER/EGFR receptor tyrosine kinases and its inhibitors/antibodies play a role in a broad spectrum of oncological diseases and treatments, and some HER3 inhibitors/antibodies are already under clinical investigation, we hypothesized that in case of HER3 co-amplifications a tumor might bear a further potential therapeutic target.

METHODS

We performed FISH analysis (MDM2, DDIT3, HER3) in 56 archived cases and subsequently performed reclassification to confirm the diagnosis of liposarcoma.

RESULTS

Next to 16 out of 56 cases needed to be re-classified, in 20 out of 54 cases, a cluster-amplification of HER3 could be detected, significantly correlating with MDM2 amplification. Our study shows that the entity of liposarcomas show specific molecular characteristics leading to reclassify archived cases by modern, established methodologies. Additionally, in 57.1% of these cases, HER3 was cluster-amplified profusely, presenting a putative therapeutic target for targeted therapy.

CONCLUSION

Our study serves as the initial basis for further investigation of the HER3 gene as a putative therapeutic target in liposarcoma.

Endobronchial Obstruction: A Case of Well-Differentiated Liposarcoma

Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) is a rare subtype of endobronchial tumor that has been rarely reported in medical literature. Due to its low incidence, distinguishing it from endobronchial lipoma poses a significant diagnostic challenge, necessitating histopathologic and cytogenetic analysis. As of today, the treatment and surveillance protocols for these neoplasms remain poorly defined, often resulting in their misclassification and treatment as endobronchial lipomas. We present a case involving a 72-year-old male who presented with worsening dyspnea and cough. Diagnostic imaging revealed an endobronchial lesion obstructing the left main bronchus. The patient underwent a flexible bronchoscopy that identified a polypoid mass causing significant obstruction, which was subsequently resected via cryoablation. Histopathology confirmed ALT/WDL, supported by genetic analysis revealing chromosomal alterations. Following the intervention, symptoms resolved, with no recurrence on follow-up imaging. Differentiating ALT/WDL from endobronchial lipomas is necessary not only because it influences treatment decisions but also because it can significantly affect the prognosis of patients diagnosed with ALT/WDL. In this case, we emphasize the importance of considering ALT/WDL in the differential diagnosis of endobronchial tumors and highlight the use of flexible bronchoscopy as a viable substitute for rigid bronchoscopy, serving not only as a diagnostic tool but also as a therapeutic method.

Soft-Tissue Sarcomas of the Genitourinary Tract with Radiologic-Pathologic Correlation

Genitourinary tract soft-tissue sarcomas are rare neoplasms with varied pathologic and clinical features. While some of these tumors may be aggressive high-grade malignancies, others are low grade with a relatively better prognosis. Given that the grade and extent of the disease are important prognostic factors in these tumors, timely diagnosis is crucial. Unfortunately, most imaging features of these malignancies are not pathognomonic, and various histologic subtypes do not manifest with typical classic imaging features. Therefore, reliable differentiation of the various histologic tumor types is not always possible based solely on the radiologic manifestations. Imaging findings need to be considered in the context of clinical history in corroboration with radiologic-pathologic correlation. The authors discuss the specific imaging and pathologic characteristics of various genitourinary tract soft-tissue sarcomas, emphasizing diagnostic difficulties and differential diagnoses. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Laparoscopic management of a gastric liposarcoma with malignant transformation from a gastric lipoma: A rare case report

INTRODUCTION AND IMPORTANCE

Liposarcoma is one of the most common mesenchymal neoplasms in adults. Among liposarcomas, gastrointestinal tract involvement is uncommon, and liposarcoma of the stomach is a particularly rare entity, In addition, few cases of gastric liposarcoma with malignant transformation from benign gastric lipoma have been reported.

PRESENTATION OF CASE

Here we present the case of a 62-year-old male patient who was diagnosed with gastric liposarcoma and managed with laparoscopic surgical resection. He was first diagnosed with subepithelial lipoma of the stomach 4 years ago and was under observation, but underwent laparoscopic distal gastrectomy due to malignant transformation of gastric lipoma. He has been following up for 1 year after surgery, and there are no recurrence or other complications to date.

CLINICAL DISCUSSION

This patient was initially diagnosed with gastric lipoma and was surgically resected after 4 years of observation to show malignant transformation. To the best of our knowledge, this case represents the first report of gastric lipoma demonstrating malignant transformation into gastric liposarcoma.

CONCLUSION

Gastric lipoma can be transformed into gastric liposarcoma, so if the size is large or the rate of size change is fast, surgical resection is recommended in the early state, and en-bloc resection including node dissection and reconstruction are desirable during surgery.

Unusual presentation and management of spindle cell lipoma: A case report

Spindle cell lipoma is a benign tumor composed of mature adipocytes and uniform spindle cells, it does not exceed usually more than 2.5 cm and can be treated surgically and does not require wide surgical margins. It must be differentiated from liposarcoma and other malignant tumours and can be differentiated based on imaging and histological features. We report a case of 67-year-old male who developed a posterior thoracic mass more than 10 years ago, that grew recently, whose imaging features was suggestive of liposarcoma, and was treated as such.

Enhancer Coamplification and Hijacking Promote Oncogene Expression in Liposarcoma

SIGNIFICANCE

Comprehensive profiling of the enhancer landscape and 3D genome structure in liposarcoma identifies extensive enhancer-oncogene coamplification and enhancer hijacking events, deepening the understanding of how oncogenes are regulated in cancer.

Clinical update on cutaneous and subcutaneous sarcomas

BACKGROUND

Cutaneous sarcomas are uncommon cancers that can have a wide range of clinical symptoms and lead to considerable cutaneous as well as systemic morbidity.

AIM

The objective of this review article is to discuss epidemiology, clinical features, diagnosis, and therapy of different types of cutaneous sarcomas.

MATERIAL AND METHODS

Literature was screened to retrieve articles from PubMed/Medline and Google Scholar and related websites. Cross-references from the relevant articles were also considered for review. Review articles, clinical studies, systematic reviews, meta-analyses, and relevant information from selected websites were included.

RESULTS AND DISCUSSION

Cutaneous sarcomas have a negative effect on the quality of life. In their diagnosis, clinical presentation and histological evaluation are crucial. Complete surgical removal is the solution for more or less all cutaneous and subcutaneous sarcomas. The prognosis for cutaneous sarcomas is generally favorable since they tend to recur locally with distant metastases only on rare occasions. Patients having advanced disease should be treated in the setting of clinical trials if possible; choices include radiation therapy and systemic medicines. The value of innovative immunotherapy cannot be determined decisively at this time due to a paucity of relevant trials.

CONCLUSION

As cutaneous sarcomas are rarely diagnosed based on clinical findings, histology plays an important role in the diagnosis. They have a relatively favorable prognosis if treated properly. Patients should be treated at specialized centres.

Paraplegia due to spinal epidural lipoma without spinal dysraphism in an adolescent patient: a case report

We report the case of a rare lipoma arising in the epidural space of a 14-year-old boy without spinal dysraphism. Lipomas are rare in pediatric soft tissue tumors, accounting for only about 4% of cases. The incidence of an intraspinal epidural lipoma without spinal dysraphism is extremely rare in pediatric patients. In this case, the patient had progressive motor deficits in the lower extremities and difficulty in urination and defecation. Magnetic resonance imaging showed an extradural tumor compressing the spinal cord at the T3-T7 level. Because of the progressive neurological deficits, we performed an emergency surgery. The tumor was completely resected en bloc, and histopathology revealed mature adipose tissue with fibrous septa, diagnosed as atypical lipomatous tumor / well-differentiated liposarcoma. The patient fully recovered and there was no tumor recurrence for 6 years since the surgery. However, re-examination using fluorescence in situ hybridization after 6 years of surgery changed the diagnosis to lipoma as no amplification of murine double-minute type 2 oncogene was observed. In liposarcoma, histopathological diagnosis using fluorescence in situ hybridization is mandatory. Our case illustrates that immunohistochemical diagnosis alone can be misleading. Hence, prompt surgery is required for progressive neuropathy.

Expression of the preadipocyte marker ZFP423 is dysregulated between well-differentiated and dedifferentiated liposarcoma

Background

Well-differentiated and dedifferentiated liposarcomas are rare soft tissue tumors originating in adipose tissue that share genetic abnormalities but have significantly different metastatic potential. Dedifferentiated liposarcoma (DDLPS) is highly aggressive and has an overall 5-year survival rate of 30% as compared to 90% for well-differentiated liposarcoma (WDLPS). This discrepancy may be connected to their potential to form adipocytes, where WDLPS is adipogenic but DDLPS is adipogenic-impaired. Normal adipogenesis requires Zinc Finger Protein 423 (ZFP423), a transcriptional coregulator of Perixosome Proliferator Activated Receptor gamma (PPARG2) mRNA expression that defines committed preadipocytes. Expression of ZFP423 in preadipocytes is promoted by Seven-In-Absentia Homolog 2 (SIAH2)-mediated degradation of Zinc Finger Protein 521 (ZFP521). This study investigated the potential role of ZFP423, SIAH2 and ZFP521 in the adipogenic potential of WDLPS and DDLPS.

Methods

Human WDLPS and DDLPS fresh and paraffin-embedded tissues were used to assess the gene and protein expression of proadipogenic regulators. In parallel, normal adipose tissue stromal cells along with WDLPS and DDLPS cell lines were cultured, genetically modified, and induced to undergo adipogenesis in vitro.

Results

Impaired adipogenic potential in DDLPS was associated with reduced ZFP423 protein levels in parallel with reduced PPARG2 expression, potentially involving regulation of ZFP521. SIAH2 protein levels did not define a clear distinction related to adipogenesis in these liposarcomas. However, in primary tumor specimens, SIAH2 mRNA was consistently upregulated in DDLPS compared to WDLPS when assayed by fluorescence in situ hybridization or real-time PCR.

Conclusions

These data provide novel insights into ZFP423 expression in adipogenic regulation between WDLPS and DDLPS adipocytic tumor development. The data also introduces SIAH2 mRNA levels as a possible molecular marker to distinguish between WDLPS and DDLPS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09379-6.

Primary pleomorphic liver liposarcoma: A case series and literature review

Primary hepatic liposarcoma is an extremely rare mesenchymal tumor that accounts for only 0.1% to 2% of primary malignant liver tumors. Due to its rarity, there is a lack of knowledge about its clinical course, management, and prognosis. Only 15 cases of primary liposarcoma of the liver have been reported since 1973. Among these 15 cases, only two involved primary liver liposarcoma with a pleomorphic subtype. Here we report the third and fourth cases of primary pleomorphic liver liposarcoma. A 57-year-old female presented with abdominal discomfort and progressive abdominal distension for two weeks. Computed tomography (CT) of her abdomen revealed a large well-defined solid nodule mass with an area of necrosis and hemorrhage occupying segment IV-B of the liver. Wide local excision was performed. She had an uneventful recovery and remained well at six months post-treatment. A 65-year-old male presented with an abdominal mass for two-month. CT demonstrated a mass in the left lobe of the liver with mixed soft tissues and fat attenuation. He underwent wide local excision. He was discharged on day three postoperatively. Histological analysis for both cases revealed liposarcoma of the liver with a pleomorphic subtype.

Survival analysis and treatment strategies for limb liposarcoma patients with metastasis at presentation

Limited data exist on patients with limb liposarcoma (LLS) with metastasis at presentation Moreover, the potential prognostic factors of this patient population are poorly documented because of its rarity. Therefore, we conducted this study to evaluate the clinicopathologic characteristics and prognostic factors for patients with metastatic LLS.All patients with LLS with metastasis at presentation from 1975 to 2016 were identified by using the Surveillance, Epidemiology, and End Results (SEER) database. The following clinical data were derived from this clinical database: age, sex, histologic grade, subtype, size of tumor, surgery, radiotherapy, chemotherapy, vital status, cause of death, and survival duration. The Kaplan-Meier method was performed to calculate median survival time and draw survivorship curves. Cox-proportional hazards regression model was used to reveal the statistical independence between various variables.The present study collected 184 cases from SEER database for survival analysis. Mean age was 57.8 years with 63.6% (n = 117) men. The 3-year overall survival (OS) and cancer-specific survival (CSS) rates of this population were 27.8% and 30.1%, respectively. Univariate analysis revealed that age, tumor grade, and surgery were significantly correlated with survival. Sex and tumor size did not reach significant predictor status of survival. Multivariate analysis revealed that age at diagnosis <60, low tumor grade, and local surgery were significantly correlated with improved OS and CSS.Patients with LLS with metastasis at diagnosis experienced quite poor prognosis. Currently, surgery for the primary tumor significantly prolonged the survival of those patients, whereas chemotherapy and radiotherapy need to be further confirmed.

Contrast-enhanced ultrasound-guided musculoskeletal biopsies: our experience and technique

OBJECTIVE

To present our experience with contrast-enhanced ultrasound (CEUS)-guided musculoskeletal soft tissue biopsies in a busy interventional clinic.

MATERIALS AND METHODS

After IRB approval was obtained and informed consent was waived, we retrospectively reviewed all CEUS-guided musculoskeletal biopsies performed from December 1, 2018 to March 2, 2020. Relevant pre-procedure imaging was reviewed. Number of samples, suspected necrosis on pre-procedure imaging, specimen adequacy for pathologic analysis, correlation with pathologic diagnosis of surgical resection specimens, and procedural complications were recorded.

RESULTS

Thirty-six CEUS-guided musculoskeletal biopsies were performed in 32 patients (mean age 57, range 26-88; 22 males, 10 females). All procedures were performed using 16-gauge biopsy needles, and all procedures provided adequate samples for pathologic analysis as per the final pathology report. Between two and seven core specimens were obtained (mean 3.7). In 30/36 cases (83%), a contrast-enhanced MRI was obtained prior to biopsy, and 10/30 (33%) of these cases showed imaging features suspicious for necrosis. In 15/36 cases, surgical resection was performed, and the core biopsy and surgical resection specimens were concordant in 14/15 cases (93%). One patient noted transient leg discomfort at the time of microbubble bursting. Otherwise, no adverse reactions or procedural complications were observed.

CONCLUSION

CEUS is an accurate way to safely target representative areas of soft tissue lesions for biopsy and can be implemented in a busy interventional clinic. Our early experience has shown this to be a promising technique, especially in targeting representative areas of heterogeneous lesions and lesions with areas of suspected necrosis on prior imaging.

Carpal tunnel syndrome caused by a giant lipoma of the hand: A case report

INTRODUCTION AND IMPORTANCE

Lipomas are common benign tumours which occur in up to 2% of the population. They are classified as giant when larger than 5 cm. Although they are usually asymptomatic, giant lipomas of the hand may cause compression of the underlying tissues.

CASE PRESENTATION

A 62-year-old Caucasian male presented to the Plastic and Reconstructive Surgery outpatient clinic with numbness and pain in his left hand. The numbness in his fingers pointed to compression of the median nerve, as well as the ulnar nerve. He presented with a rapidly progressive swelling in his left palm. An MRI scan of the hand was made, which showed a lipoma of approximately 8,5 cm in diameter. The swelling was surgically removed and sent for histopathological analysis, which confirmed the diagnosis of benign giant lipoma of the hand. Two weeks postoperatively, pain and numbness significantly decreased.

CLINICAL DISCUSSION

Neural injury in carpal tunnel syndrome is related to the duration and degree of compression. A giant lipoma is considered malignant until proven otherwise since variants with high potential for metastasizing exist. Distinguishing between a benign tumour and a malignant lipoma is essential, since a more radical treatment plan might be required.

CONCLUSION

Giant lipomas of the hand are a rare cause of carpal tunnel syndrome and a malignant variant should always be suspected. A preoperative MRI scan should be performed. Rapid en bloc excision is necessary in case of compression of the underlying tissues.

Rare Case of Primary Pulmonary Pleomorphic Liposarcoma Treated With Multimodal Therapy

Background: Pleomorphic liposarcoma (PLS) is a very rare type of primary pulmonary sarcoma. Clinical data about these tumors are limited, and optimal treatment has not yet been defined. Case Report: A 32-year-old male presented with pain and heaviness over the right chest. Contrast-enhanced computed tomography (CECT) of the chest showed a heterogeneous hypodense pleural-based mass and a mediastinal mass. The patient was treated with chemoradiotherapy, followed by excision and adjuvant chemotherapy. Seven months after completion of treatment, he presented with an abdominopelvic mass and soft tissue peritoneal deposits. The mass was resected, and second line chemotherapy resulted in a partial response. The patient was routinely followed. Six months after completion of the second round of chemotherapy, CECT showed multiple soft tissue deposits in the right lumbar region, right hemipelvis, and presacral region with no evidence of pulmonary disease. Chemotherapy elicited a partial response. Three years from the date of diagnosis, the patient was alive with stable disease. Conclusion: This case is unique because of the rare primary site of PLS presentation and the rare presentation of peritoneal metastasis. Citing such cases would help us to define adequate treatment protocols for this aggressive tumor.

Anti-tumor effects of anti-PD-1 antibody, pembrolizumab, in humanized NSG PDX mice xenografted with dedifferentiated liposarcoma

The efficacy of an immune checkpoint blockade has been demonstrated against various types of cancer, but its suitability has not been fully proven for therapies specifically targeting sarcoma. We conducted a pan-cancer tumor data analysis to identify key immune-related variables strongly associated with sarcoma prognosis, and we explored whether these expected factors are functionally correlated with anti-PD-1 therapy in humanized (Hu) NOD.Cg-Prkdc^scidIl2rg^tm1Wjl/SzJ (NSG) mice xenografted with dedifferentiated liposarcoma (DDLPS). We found that an abundance of hCD8⁺ T cells and hNK cells was functionally associated with anti-PD-1 effects in the Hu-NSG DDLPS mice. Phenotypically, these cells were shown to be hCD8⁺IFNγ⁺, hCD8⁺PD-1⁺, hCD8⁺Ki-67⁺, hCD56⁺IFNγ⁺, hCD56⁺PD-1⁺, and hCD56⁺Ki-67⁺ cells and were enriched in splenocytes and tumor-infiltrating lymphocytes (TILs) of Hu-NSG DDLPS mice treated with anti-PD-1 antibody. Moreover, a considerable increase in activated hCD56⁺NKp46⁺NKG2D⁺ NK cells was also detected. Our findings suggest that hCD8⁺ T and hNK subsets play a pivotal role in anti-DDLPS tumor effects of anti-PD-1 therapy. The results provide clinical reference for advanced anti-PD-1 therapy targeting sarcoma tumors including DDLPS.

Primary myxoid liposarcoma of the pelvis: An unusual location

Myxoid liposarcoma is the second most common type of liposarcoma, normally located in deep tissues of the lower extremities and rarely in the mesenchyma of abdomen and pelvis We present a patient who, incidentally, showed a large pelvis mass. CT and MR revealed a loculated lesión with hypodense areas and very high signal in T2 respectively as well as heterogeneous contrast enhancement. The imaging findings of pelvic myxoid liposarcoma are nonspecific, but nevertheless a painless mesenchymal mass should be considered when we see lesions of myxoid aspect in the pelvic area without a clear relationship with defined anatomic structures.

Clear cell renal carcinoma synchronous with dedifferentiated liposarcoma: a case report and review of the literature

BACKGROUND

Multiple primary malignant neoplasms are not frequent but are increasing in incidence. Some of them are associated with genetic syndromes such as von Hippel-Lindau syndrome and Li-Fraumeni syndrome. Dedifferentiated liposarcoma is one of the rarest soft tissue tumors, and clear cell renal carcinoma is the most frequent kidney cancer. The concomitant presence of these tumors is extremely rare; however, some cases have been reported, none of them presenting with liposarcoma of the limbs. We report an interesting case of a patient with synchronous multiple primary tumors presenting with a very rare liposarcoma associated with renal cell carcinoma (a very rare association). A review of the literature and a collection of similar cases published previously are also provided.

CASE PRESENTATION

We report a case of a 62-year-old Hispanic man who presented to our institution with a left thigh mass compatible with dedifferentiated liposarcoma synchronous with metastatic clear cell renal carcinoma. Multiple treatment lines were provided with no response, with a further metastatic transformation. Genetic analysis by liquid biopsy showed some mutations that were not susceptible to targeted therapy. At the time of this report, the patient is undergoing palliative care because his nonresponsive metastatic disease persists.

CONCLUSIONS

We present the first reported case of clear cell renal carcinoma synchronous with dedifferentiated liposarcoma of a limb. The association between renal cell carcinoma and dedifferentiated liposarcoma is unusual, and there are few reports of this presentation in the literature. More research about these tumors along with genetic tests needs to be performed to seek a better understanding of the fundamental basis of this rare association.

CT and MRI features of tumors and tumor-like lesions in the abdominal wall

Masses involving the abdominal wall are common in clinical practice and have many etiologies, including tumors and tumor-like lesions. Abdominal wall tumors include primary and secondary tumors, the former of which constitute a heterogeneous group of soft tissue tumors with their own unique spectrum. Tumor-like lesions, such as hernias, are more common and must be distinguished from true tumors. Medical imaging is valuable for discovering, diagnosing, and evaluating the extent of abdominal wall masses. With the increasing application of computed tomography (CT) and magnetic resonance imaging (MRI), determining a diagnosis or narrowing the differential diagnosis is often possible, thus facilitating effective management. In this article, we comprehensively review the spectrum of common abdominal wall masses and present the CT and MRI features of typical cases in our hospital. A systematic stepwise diagnostic approach is also proposed for clinical practice.

Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma with Myxoid Stroma in a Hereditary Retinoblastoma Survivor

Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDL) is an indolent, locally aggressive mesenchymal neoplasm, most often confined to the lower extremities and retroperitoneum and rarely identified in the orbit. Diagnosis of ALT/WDL can be challenging due to its frequent morphologic overlap with benign adipose lesions and other more aggressive liposarcoma subtypes, including myxoid liposarcoma. We describe a 26-year-old female with a history of hereditary retinoblastoma and external-beam radiotherapy to the orbit, who developed orbital liposarcoma. Although initial morphologic assessment raised the consideration of myxoid liposarcoma, subsequent fluorescein in situ hybridization studies demonstrated MDM2 and DDIT3 coamplification without DDIT3 rearrangement, supporting the diagnosis of ALT/WDL with myxoid stroma. The literature review of previously reported orbital myxoid liposarcomas revealed a morphologic overlap of documented tumors with ALT/WDL, dedifferentiated liposarcoma, and pleomorphic liposarcoma with myxoid stroma as well as an absence of immunohistochemical and molecular genetic data supportive of the diagnosis of myxoid liposarcoma. This case emphasizes the potential overlap of ALT/WDL with myxoid liposarcoma and the increasing importance of molecular genetic studies in the diagnosis, prognosis, and management of orbital liposarcoma.

A huge mediastinal, well-differentiated liposarcoma with heterogenous smooth muscle differentiation: a case report

Liposarcoma is one of the most common mesenchymal tumors, although liposarcomas that occur in the mediastinum are uncommon. We recently encountered a case of mediastinal well-differentiated liposarcoma with secondary myxoid changes and smooth muscle differentiation in a 54-year-old man. The patient reported a 20-day history of chest pain, and thorax computed tomography revealed a large and multilobulated mass with heterogeneous density in the posterior and anterior mediastinum, which extended to the right hemithorax. Resection was performed and a pathological analysis subsequently confirmed a diagnosis of well-differentiated liposarcoma. The patient experienced recurrence at 15 months after the surgery and subsequently died of heart failure.

Dedifferentiated Liposarcoma With Myofibroblastic Differentiation

CONTEXT.—

Liposarcoma is divided into myxoid, pleomorphic, well-differentiated, and dedifferentiated subtypes. Dedifferentiated liposarcoma displays the greatest histomorphologic diversity, including a subset with myofibroblastic differentiation that shares similarities with a spectrum of reactive, benign, and malignant soft tissue lesions. Misdiagnosis may lead to deleterious consequences, as dedifferentiated liposarcoma differs significantly in its prognosis and treatment from its mimics.

OBJECTIVE.—

To review the clinicopathologic, immunohistochemical, and molecular features of the myofibroblastic variant of dedifferentiated liposarcoma as well as the key distinguishing features from its mimics.

DATA SOURCES.—

Review of pertinent literature on major features and current understanding of dedifferentiated liposarcoma with myofibroblastic differentiation.

CONCLUSIONS.—

The myofibroblastic variant of dedifferentiated liposarcoma is an uncommon and underrecognized sarcoma with several important differential diagnoses, and likely represents the major subset of aggressive retroperitoneal tumors that may have been misdiagnosed as desmoid-type fibromatosis, inflammatory myofibroblastic tumor, or another type of sarcoma in the past.

The combination of gemcitabine and docetaxel arrests a doxorubicin-resistant dedifferentiated liposarcoma in a patient-derived orthotopic xenograft model

Liposarcoma (LS) is a chemotherapy-resistant disease. The aim of the present study was to find precise therapy for a recurrent dedifferentiated liposarcoma (DDLS) in a patient-derived orthotopic xenograft (PDOX) model. The DDLS PDOX models were established orthotopically in the right inguinal area of nude mice. The DDLS PDOX models were randomized into five groups: untreated; doxorubicin (DOX); gemcitabine (GEM) combined with docetaxel (DOC); pazopanib (PAZ); and yondelis (YON). On day 15, all mice were sacrificed. Measurement of tumor volume and body weight were done two times a week. The DDLS PDOX was resistant to DOX (P > 0.184). YON suppressed tumor growth significantly compared to control group (P < 0.027). However, only GEM combined with DOC arrested the tumor growth (P < 0.001). These findings suggest that GEM combined with DOC has clinical potential for this and possibly other DDLS patients.

T2, T2* and spin coupling ratio as biomarkers for the study of lipomatous tumors

BACKGROUND

Subcutaneous fat may have variable signal intensity on T2w images depending on the choice of imaging parameters. However, fatty components within tumors have a different degree of signal dependence on the acquisition scheme. This study examined the use of T2, T2^* relaxometry and spin coupling related signal changes (Spin Coupling ratio, SCr) on two different imaging protocols as clinically relevant descriptors of benign and malignant lipomatous tumors.

MATERIALS AND METHODS

20 patients with benign lipomas or liposarcomas of variable histologic grade were examined at an 1.5 T scanner with Multi Echo Spin Echo (MESE) different echo spacing (ESP) in order to produce bright fat T2w images (ESP: 13.4 ms, 25 equidistant echoes) and dark fat images (ESP: 26.8 ms with 10 equidistant echoes). T2^* relaxometry acquisition comprises 4 sets of in-opposed echoes (2.4-19.2 ms, ESP: 2.4 ms) Multi Echo Gradient Echo (MEGRE) sequence. All parametric maps were calculated on a pixel basis.

RESULTS

Significant differences of SCr were found for five different types of lipomatous tumors (Pairwise t-test with Bonferroni correction): lipomas, well differentiated liposarcomas, myxoid liposarcomas, pleomorphic liposarcomas and poorly differentiated liposarcomas. SCr surpassed the classification performance of T2 and T2^* relaxometry.

DATA CONCLUSION

A novel biomarker based on spin coupling related signal loss, SCr, is indicative of lipomatous tumor histological grading. We concluded that T2, T2^* and SCr can be used for the classification of fat containing tumors, which may be important for biopsy guidance in heterogeneous masses and treatment planning.

Bromodomain and extraterminal proteins foster the core transcriptional regulatory programs and confer vulnerability in liposarcoma

Liposarcomas (LPSs) are a group of malignant mesenchymal tumors showing adipocytic differentiation. Here, to gain insight into the enhancer dysregulation and transcriptional addiction in this disease, we chart super-enhancer structures in both LPS tissues and cell lines. We identify a bromodomain and extraterminal (BET) protein-cooperated FUS-DDIT3 function in myxoid LPS and a BET protein-dependent core transcriptional regulatory circuitry consisting of FOSL2, MYC, and RUNX1 in de-differentiated LPS. Additionally, SNAI2 is identified as a crucial downstream target that enforces both proliferative and metastatic potentials to de-differentiated LPS cells. Genetic depletion of BET genes, core transcriptional factors, or SNAI2 mitigates consistently LPS malignancy. We also reveal a compelling susceptibility of LPS cells to BET protein degrader ARV-825. BET protein depletion confers additional advantages to circumvent acquired resistance to Trabectedin, a chemotherapy drug for LPS. Moreover, this study provides a framework for discovering and targeting of core oncogenic transcriptional programs in human cancers.

Liposarcoma (LPS) is a rare cancer that can acquire resistance to chemotherapy. Here, the authors map super-enhancers in LPS, finding BET-protein dependent mechanisms that can be targeted by a BET protein degrader, which also can overcome acquired resistance to chemotherapy in LPS.

Pleomorphic liposarcoma of chest wall: a rare entity with challenging management

Pleomorphic liposarcoma is the rarest subtype of liposarcoma, with a high recurrence rate and poor prognosis. We present the case of young man with a rapidly growing large anterior chest wall liposarcoma that was excised, but he suffered 3 local recurrences in one year, showing the aggressive nature of the disease. If not completely resected with a tumor-free margin, the patient may have to endure multiple extensive surgeries in quick succession, increasing the chances of metastasis and a fatal outcome. Pleomorphic liposarcoma should be radically excised along with radiotherapy and strict follow-up of such patients.

Practical approach to primary retroperitoneal masses in adults

Primary retroperitoneal masses constitute a heterogeneous group of uncommon lesions and represent a challenge due to overlapping imaging findings. Most are malignant lesions. Although they are more prevalent in adults, they can occur at any age. Such lesions are classified as primary when they do not originate from a specific retroperitoneal organ and are divided, according to the image findings, into two major groups: solid and cystic. The clinical findings are nonspecific and vary depending on the location of the lesion in relation to adjacent structures, as well as on its behavior. The main imaging methods used for staging and surgical planning, as well as for selecting the biopsy site and guiding the biopsy procedure, are computed tomography and magnetic resonance imaging. In most cases, the treatment is challenging, because of the size of the lesions, vascular involvement, or involvement of adjacent organs. In this article, we present a review of the retroperitoneal anatomy and a practical approach to the main imaging features to be evaluated, with a view to the differential diagnosis, which can guide the clinical management.

Comprehensive Bioinformatic Analysis Genes Associated to the Prognosis of Liposarcoma

BACKGROUND Liposarcoma is the most common type of soft tissue sarcoma, but its molecular mechanism is poorly defined. This study aimed to identify genes crucial to the pathogenesis of liposarcoma and to explore their functions, related pathways, and prognostic value. MATERIAL AND METHODS Differentially expressed genes (DEGs) in the GSE59568 dataset were screened. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted to investigate the DEGs at the functional level. Protein-protein interaction (PPI) networks and module analysis were applied to identify hub genes from among the DEGs. The GSE30929 dataset was used to validate the relationship between hub genes and the distant recurrence-free survival (DRFS) of liposarcoma patients using Cox model analysis. RESULTS A total of 1111 DEGs were identified. GO and KEGG pathway analysis indicated that the DEGs were mainly associated with lipopolysaccharides and pathways in cancer. The PPI network and module analysis identified 10 hub genes from the DEG network. The Cox model identified 3 genes (NIP7, RPL10L, and MCM2) significantly associated with DRFS. The risk score calculated by the Cox model of the NIP7-RPL10L-MCM2 signature could largely predict the 1-, 3-, and 5-year DRFS of liposarcoma patients, and the prognostic value was even higher for subtypes of liposarcoma. CONCLUSIONS This study identified genes that might play critical roles in liposarcoma pathogenesis as well as a 3-gene-based signature that could be used as a candidate prognostic biomarker for patients with liposarcoma.

Giant primary liposarcoma of the anterior mediastinum: A case report

RATIONALE

Liposarcoma is a cancerous mesenchymal tumor and the most common soft-tissue sarcoma that starts in the adipose tissue. Liposarcoma is commonly found in lower extremities and retroperitoneum, but rarely occurs in the mediastinum.

PATIENT CONCERNS

A 63-year-old male was referred to our clinic with a 6-month history of chronic cough and dyspnea.

DIAGNOSE

Chest x-rays demonstrated a large mass occupying the left hemithorax. Contrast-enhanced computed tomography (CT) revealed a large mass in the anterior mediastinum, which caused the extrinsic compression of the main and left pulmonary artery and the right shift of mediastinum. Diagnosis of liposarcoma was confirmed by microscopic examination and immunohistochemistry analysis.

INTERVENTIONS

The patient underwent a thoracotomy for resection of the mediastinal lesion via left thoracic approach.

OUTCOMES

The patient discharged without any complications and has been continuing to follow up in clinic without any complaints.

LESSONS

The primary mediastinal liposarcoma is rare, and we recommend that the liposarcoma should be considered in the differential diagnosis of a patient presenting with a mediastinal mass.

Primary Myxoid Liposarcoma of the Greater Omentum in a Rhesus Macaque (Macaca mulatta)

We here report a spontaneous case of primary myxoid liposarcoma of the greater omentum with subsequent transperitoneal recurrence. The primary mass was incidentally found during an exploratory laparotomy for a presumed diagnosis of trichobezoar or phytobezoar and was removed surgically. Histopathologic examination of the mass revealed the presence of a myxoid liposarcoma. Eleven months later, recurrence with severe transperitoneal sarcomatosis of the myxoid liposarcoma was noted and confirmed by necropsy and histopathology. A review of the literature revealed that liposarcoma in NHP conforms to the behavior and prognosis of this neoplasm in humans.

Primary endobronchial liposarcoma successfully resected via bronchoscopy: A rare case report with genetic analysis

Liposarcoma is the most common type of soft-tissue sarcoma, and predominantly originates from the extremities and retroperitoneal cavity. However, primary endobronchial liposarcoma is extremely rare. The present study reports on the case of a 54-year-old man, a smoker, diagnosed with primary endobronchial atypical lipomatous tumor/well-differentiated liposarcoma (ALT-WDLS), which was successfully resected via bronchoscopy. Chest computed tomography (CT) revealed a neoplasm in the left main bronchus measuring 12.8×7.8 mm. Bronchoscopy demonstrated multiple roundish, pedunculated, polypoid masses in the left main bronchus. Bioptic specimens were obtained from the roundish masses, and pathological examination revealed an adipose tissue-derived tumor. The masses were completely resected during the second bronchoscopy under general anesthesia. Histopathological examination of the radical resection specimen revealed that it was an ALT-WDLS. The patient showed good quality of life at the 6-month postoperative follow-up without evidence of recurrence. Immunohistochemistry was completed with the human homologue of murine double-minute type 2 (MDM2) (+), cyclin-dependent kinase 4 (CDK4) (+), p16 (+), S-100 (+), Ki-67 (+), cluster of differentiation 34 (CD34) (+) and retinoblastoma protein (+), confirming ALT-WDLS. However, the fluorescence in situ hybridization assay revealed no amplification of MDM2 and CDK4 in the ALT-WDLS. To the best of our knowledge, the present case report is the first to describe the clinicopathologic features and genetic analysis of endobronchial liposarcoma. Although rare, this case is a reminder that clinicians should consider the possibility of this rare endobronchial tumor in patients with nonspecific symptoms including chronic cough, chest pain and recurrent pneumonia. As in this case, endoscopic treatment provided an excellent clinical outcome in patients with primary endobronchial ALT-WDLS.

Liposarcoma of the glottis: A report of an unusual diagnosis in an unusual location

Liposarcoma of the larynx is a rare entity, typically well differentiated with a good prognosis. We present a patient who presented to ENT clinic with a 3-month history of hoarseness. Contrast-enhanced computed tomography of the neck demonstrated a 2.5-cm mass of the true vocal cord, which biopsy demonstrated to be dedifferentiated liposarcoma of the larynx. The patient went on to total laryngectomy with planned adjuvant radiation therapy. The presentation and imaging findings of laryngeal liposarcoma are nonspecific, but this neoplasm should be considered in the differential of masses in the head and neck.

CT and MRI of superficial solid tumors

Superficial solid masses are common conditions in clinical practice, however, some of which can be easily diagnosed and others would be difficult. Although imaging of superficial masses is not always characteristic, it would be helpful to give a definitive diagnosis or narrow a differential diagnosis. Crossing-section imaging can depicture the masses directly, find some pathognomonic signs and demonstrate their relationship with adjacent structures, which can provide decision support for clinician's reference. Computed tomography (CT) can be used to detect calcifications and bone erosion which could not be seen on radiographs. Magnetic resonance imaging (MRI) is the preferred way for evaluating soft tissue lesions and provides information on hemorrhage, necrosis, edema, cystic and myxoid degeneration, and fibrosis. Other advantages of MRI are its superior soft tissue resolution and any profile imaging, which can aid the assessment of extension and adjacent infiltration. Positron emission tomography (PET)/CT and PET/MRI have been increasingly used in bone and soft tissue sarcomas and provides advantages in the initial tumor staging, tumor grading, therapy assessment, and recurrence detection. Therefore, imaging examination can play an important role in treatment decision making for superficial solid tumors. Here we review the important conditions presenting as superficial mass and show the imaging of typical cases diagnosed in our hospital.

Review of past and present clinical cases with a view to future treatment options

In the 10 years that have elapsed since trabectedin was first granted approval in Europe for treatment of advanced soft tissue sarcoma (STS), other cytotoxic agents and targeted therapies have been approved and numerous randomized controlled trials have been completed or are underway. As an academic exercise and positive proof of the advances in STS management that have occurred during the past decade, it is interesting to compare current and future treatment approaches. In this review, present and future treatment approaches are examined by case study for three STS subtypes: uterine leiomyosarcoma, abdominal dedifferentiated liposarcoma and malignant solitary fibrous tumor.

Prediction of clinical outcome and survival in soft-tissue sarcoma using a ten-lncRNA signature

The prognostic value of long non-coding RNAs (lncRNAs) in patients with soft-tissue sarcoma has rarely been unraveled. The aim of the study was to find a lncRNA signature to predict the clinical outcome and survival in soft-tissue sarcoma based on the high-throughput RNA-seq data from The Cancer Genome Atlas (TCGA) database. The lncRNAs which closely correlated with overall survival in 258 soft-tissue sarcoma patients were identified with Cox proportional regression model. Ten lncRNAs, including RP11-560J1.2, AP001432.14, RP4-665J23.1, LINC00680, AC006129.2, RP11-230G5.2, BACH1-IT2, RP11-274B21.9, RP11-504A18.1 and RP11-713P17.3, were selected to calculate a risk score. The risk score could effectively predict patients’ outcome, such as the status of mitotic count of tumor cells, person neoplasm cancer and residual tumor. More inspiringly, the risk score generated from the 10-lncRNA signature was an independent prognostic indicator for soft-tissue sarcoma patients. Overall, this 10-lncRNA signature gains the potential as an effective prognostic tool for soft-tissue sarcoma as part of the integrated clinical RNA-seq program.