Liposarcomas: diagnostic pitfalls and new insights

Dedifferentiated liposarcoma of the extremities: a Korean multi-center study of 107 cases

BACKGROUND

Dedifferentiated liposarcoma of the extremities (DDL-E) is rare in comparison to that of the retroperitoneum. Its clinical features and surgical principle for resection margins at the dedifferentiated and the well-differentiated components are yet to be elucidated.

METHODS

This retrospective multi-center study examined patients diagnosed with DDL-E from August 2004 to May 2023 at 5 sarcoma centers. Clinical features, oncologic outcomes, and prognostic factors were analyzed.

RESULTS

A total of 107 patients were reviewed. The 5-year local recurrence free survival (LRFS), metastasis-free survival (MFS) and disease specific survival (DSS) were 84.7%, 78.6%, and 87.8%, respectively. Other primary malignancies and extrapulmonary metastasis were observed in 27 and 4 patients, respectively. The independent risk factor for local recurrence was R1/2 margin at the dedifferentiated component of the tumor. Metastasis was associated with tumor size in univariate analysis. The independent risk factor for DSS was tumor grade. Previous unplanned excision, de novo presentation, tumor depth, absence of the well-differentiated component, infiltrative border, R1/2 margin at the well-differentiated component were not associated with oncologic outcomes.

CONCLUSIONS

This is the largest study examining DDL-E to-date. Localized DDL-E has low potential for metastasis and carries an excellent prognosis. Other primary malignancy and extrapulmonary metastasis are more frequent in DDL-E, thus close monitoring of other sites during follow-up is recommended. While wide resection margin is the standard surgical approach for DDL-E, further investigation into moderated wide resection margin at the well-differentiated component is warranted.

Pathogenetic and molecular classifications of soft tissue and bone tumors: A 2024 update

Soft tissue and bone tumors comprise a wide category of neoplasms. Their diversity frequently raises diagnostic challenges, and therapeutic options are continuously developing. The therapeutic success rate and long-term prognosis of patients have improved substantially due to new advances in immunohistochemical and molecular biology techniques. A fundamental contribution to these achievements has been the study of the tumor microenvironment and the reclassification of new entities with the updating of the molecular pathogenesis in the revised 5th edition of the Classification of Soft Tissue Tumors, edited by the World Health Organization. The proposed molecular diagnostic techniques include the well-known in situ hybridization and polymerase chain reaction methods, but new techniques such as copy-number arrays, multiplex probes, single-nucleotide polymorphism, and sequencing are also proposed. This review aims to synthesize the most recent pathogenetic and molecular classifications of soft tissue and bone tumors, considering the major impact of these diagnostic tools, which are becoming indispensable in clinicopathological practice.

MRI Differential Diagnosis and Guidance for Puncture Biopsy of Musculoskeletal Dedifferentiated Liposarcoma and Well Differentiated Liposarcoma

Objective

The study aimed to investigate the significantly different imaging characteristics of musculoskeletal dedifferentiated liposarcoma (DDLP) and well differentiated liposarcoma (WDLP) on MRI, which in turn could guide puncture biopsy.

Materials and Methods

This study included 14 patients with DDLP and 16 patients with WDLP, all of whom were confirmed by histopathological examination. The MRI manifestations of these two pathologies were retrospectively reviewed and compared. Furthermore, a step-by-step procedure regarding preoperative puncture biopsy of fatty masses that are suspicious for WD/DD was designed.

Results

Fatty signals can be found in almost all WDs, with a greater proportion of non-fatty areas in DD compared to WD, and it is reasonable to consider WD more likely when the non-fatty areas of the tumor are <25% (p < 0.05), while it is reasonable to consider DD more likely when the non-fatty areas of the tumor are >50% (p < 0.05), and the MRI signals in DD are more complex, inhomogeneous (p < 0.01), usually showed significant enhancement (p < 0.01), and the margins of the tumor were usually indistinct (p < 0.01); and imaging features such as tumor size, vascularity, necrosis, and peritumoral edema did not serve as distinguishing features between the two (p > 0.05).

Conclusion

DD has a greater proportion of non-fatty components, with more complex and inhomogeneous MRI signals, and typically shows significant enhancement, with usually indistinct margins of the tumor, in which the inhomogeneous manifestations are associated with the histological components. The possibility of DD should be considered in fatty tumors with non-fatty areas > 25%, for which puncture biopsy is necessary, while simultaneous puncture of low, moderate, high-signal areas within the non-fatty area could improve the accuracy of preoperative puncture pathology.

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.

Intraperitoneal Liposarcoma: A Case Report and Literature Review of a Rare Entity

Liposarcoma is a rare soft-tissue neoplasm originating from adipocytes. The exact cause of liposarcoma is unknown and symptoms vary depending on the tumor's location. A 49-year-old man presented to the emergency room complaining of epigastric pain radiating to the back and right upper quadrant. Cross-sectional imaging revealed a large upper abdominal mass that was thought to be a gastrointestinal stromal tumor (GIST) arising from the duodenum at first. The patient underwent en-bloc resection of the mass and was planned for adjuvant chemotherapy. Subsequently, multiple tissue samples were examined, leading to the final diagnosis of de-differentiated liposarcoma. The patient eventually developed multiple recurrences and was subjected to re-resection surgeries and three different chemotherapy regimens. Given the rarity of the disease, no standardized therapy plan is available, highlighting the need for more case reports/series and trials to broaden our understanding of this disease.

Unmasking the Masquerade: Fine-Needle Aspiration Diagnosis of Dedifferentiated Liposarcoma Clinically Mimicking Lymphoma

A preoperative diagnosis of dedifferentiated liposarcomas (DDLPS) on fine-needle aspiration cytology (FNAC) is rare with scarce indexed literature. Herein, we describe a case of DDLPS diagnosed on fine needle aspiration which was presumed to be a lymphoma clinically and radiologically.

Superficial dedifferentiated liposarcoma: A clinicopathologic study

INTRODUCTION

Dedifferentiation occurs in approximately 10% of atypical lipomatous tumors/well-differentiated liposarcomas (ALT/WDLPS), primarily in retroperitoneal or deep-seated tumors, conferring metastatic potential. Superficial dedifferentiated liposarcoma (sDDLPS) is rare, and its progression and natural history are poorly documented.

METHODS

We performed a 15-year retrospective review of our pathology database to identify cases of DDLPS in the skin or subcutaneous tissue. Diagnosis of primary sDDLPS required evidence of non-lipogenic sarcoma in the skin or subcutis, with concurrent ALT/WDLPS and/or MDM2 amplification.

RESULTS

We identified 14 cases of DDLPS involving skin or subcutis: 7 primary sDDLPS and 7 secondary lesions (3 from recurrent deep DDLPS and 4 from metastasis). Primary sDDLPS cases (4 females, 3 males; median age: 74) mainly presented as undifferentiated spindle cell or pleomorphic sarcoma. Tumor grades were grade 2 (5 cases) and grade 3 (2 cases), with three cases also showing grade 1 areas. MDM2 amplification was confirmed in 6 sDDLPSs for which FISH was successfully performed. Follow-up available for 6 sDDLPS patients showed 2 local recurrences, treated with re-excision and radiation therapy, with all disease-free at last follow-up (5-126 months). Of the 7 secondary cases, 2 had ongoing disease after multiple recurrences, 1 was disease-free, and all 4 with cutaneous metastasis died of disease (follow-up range: 24-263 months).

CONCLUSION

These findings emphasize the importance of distinguishing between primary sDDLPS and secondary lesions due to their distinct prognoses. Metastasis or superficial extensions from deep DDLP correlate with a considerably worse prognosis than those originating in superficial tissues.

Giant liposarcoma of the thigh: A case report

Liposarcoma is a tumor derived from primitive cells that undergo adipose differentiation. They comprise 10%-35% of all soft tissue sarcomas. We present a 46-year-old female patient with a 4-year history of a giant swelling on the lateral aspect of the left thigh. Wide local excision of the mass was performed and histopathological analysis revealed a well-differentiated liposarcoma. Liposarcomas commonly appear in the extremities and have distinct features on imaging studies. Surgical treatment and histology are the most important prognostic factors for patients with lipomatous tumors, as complete surgical excision reduces local recurrence rate.

Genetic, Epigenetic and Transcriptome Alterations in Liposarcoma for Target Therapy Selection

Liposarcoma (LPS) is one of the most common adult soft-tissue sarcomas (STS), characterized by a high diversity of histopathological features as well as to a lesser extent by a spectrum of molecular abnormalities. Current targeted therapies for STS do not include a wide range of drugs and surgical resection is the mainstay of treatment for localized disease in all subtypes, while many LPS patients initially present with or ultimately progress to advanced disease that is either unresectable, metastatic or both. The understanding of the molecular characteristics of liposarcoma subtypes is becoming an important option for the detection of new potential targets and development novel, biology-driven therapies for this disease. Innovative therapies have been introduced and they are currently part of preclinical and clinical studies. In this review, we provide an analysis of the molecular genetics of liposarcoma followed by a discussion of the specific epigenetic changes in these malignancies. Then, we summarize the peculiarities of the key signaling cascades involved in the pathogenesis of the disease and possible novel therapeutic approaches based on a better understanding of subtype-specific disease biology. Although heterogeneity in liposarcoma genetics and phenotype as well as the associated development of resistance to therapy make difficult the introduction of novel therapeutic targets into the clinic, recently a number of targeted therapy drugs were proposed for LPS treatment. The most promising results were shown for CDK4/6 and MDM2 inhibitors as well as for the multi-kinase inhibitors anlotinib and sunitinib.

Primary lipoblastic nerve sheath tumor in an inguinal lymph node mimicking metastatic tumor: a case report and literature review

Lipoblastic nerve sheath tumors of soft tissue are characterized as schwannoma tumors that exhibit adipose tissue and lipoblast-like cells with signet-ring morphology. They have been documented to arise in various anatomic locations, including the thigh, groin, shoulder, and retroperitoneum. However, to our knowledge, this tumor has not been previously reported as a lymph node primary. We present herein the first case of a benign primary lipoblastic nerve sheath tumor arising in an inguinal lymph node in a 69-year-old man. Microscopic examination revealed a multinodular tumor comprising fascicles of spindle cells, as well as adipocytic and lipoblast-like signet-ring cell component in the context of schwannoma. Despite the presence of some bizarre cells with nuclear atypia, no obvious mitotic activity or necrosis was observed. Immunohistochemical analysis showed strong and diffuse expression of S-100, SOX10, CD56, and NSE in the spindle cells as well as in the signet-ring lipoblast-like cells and the mature adipocytes. Sequencing analysis of the neoplasm identified six non-synonymous single nucleotide variant genes, specifically NF1, BRAF, ECE1, AMPD3, CRYAB, and NPHS1, as well as four nonsense mutation genes including MRE11A, CEP290, OTOA, and ALOXE3. The patient remained alive and well with no evidence of recurrence over a period of ten-year follow-up.

Primary and secondary tumors of the peritoneum: key imaging features and differential diagnosis with surgical and pathological correlation

Peritoneal malignancies represent a diagnostic challenge for abdominal radiologists, oncologists, surgeons and pathologists in multidisciplinary teams, who must address their differential diagnosis, staging and treatment. In this article, we explain the pathophysiology of these processes and lay out the role of different imaging techniques in their evaluation. Then, we review the clinical and epidemiological aspects, the main radiological features and the therapeutic approaches for each primary and secondary peritoneal neoplasm, with surgical and pathological correlation. We further describe other rare peritoneal tumors of uncertain origin and a variety of entities that may mimic peritoneal malignancy. Finally, we summarize the key imaging findings of each peritoneal neoplasm to facilitate an accurate differential diagnosis that may impact patient management.Clinical relevance statementImaging plays an essential role in the evaluation of peritoneal malignancies, assessing their extension, detecting unfavorable sites of involvement and facilitating an accurate differential diagnosis, helping to choose the best therapeutic approach.

A Rare Case of Primary Mesenteric Liposarcoma

Primary mesenteric liposarcoma is a rare soft tissue malignant neoplasm. The authors present a case of a 42-year-old male with pain in the abdomen and abdominal mass which showed a desmoid tumor on biopsy and CT shows a mesenteric mass present. The patient underwent exploratory laparotomy and a large tumor was excised. The specimen was sent for histopathology and showed dedifferentiated liposarcoma of the mesentery. Immunohistochemistry showed the tumor cells are diffusely positive for mouse double minute 2 (MDM2), p16, and show patchy positivity for the cluster of differentiation (CD) 34. The cells are negative for smooth muscle actin (SMA), desmin, S100, and ckit. After the surgery, the patient recovered well and was given adjuvant chemotherapy with doxorubicin, ifosfamide, and mesna. The patient has no signs or symptoms of recurrence to date. In this case, the combination of surgery and chemotherapy has shown to have a good clinical outcome.

Evaluation of Classic and Quantitative Imaging Features in the Differentiation of Benign and Atypical Lipomatous Soft Tissue Tumors Using a Standardized Multiparametric MRI Protocol: A Prospective Single-Centre Study in 45 Patients

Background: Discrimination between benign and atypical lipomatous tumors (ALT) is important due to potential local complications and recurrence of ALT but can be difficult due to the often-similar imaging appearance. Using a standardized MRI protocol, this study aimed to rank established and quantitative MRI features by diagnostic value in the differentiation of benign and atypical lipomatous tumors and to develop a robust scoring system. Methods: Patients with clinical or sonographic suspicion of a lipomatous tumor were prospectively and consecutively enrolled from 2015 to 2019 after ethic review board approval. Histology was confirmed for all ALT and 85% of the benign cases. Twenty-one demographic and morphologic and twenty-three quantitative features were extracted from a standardized MRI protocol (T1/T2-proton-density-weighting, turbo-inversion recovery magnitude, T2* multi-echo gradient-echo imaging, qDIXON-Vibe fat-quantification, T1 relaxometry, T1 mapping, diffusion-weighted and post-contrast sequences). A ranking of these features was generated through a Bayes network analysis with gain-ratio feature evaluation. Results: Forty-five patients were included in the analysis (mean age, 61.2 ± 14.2 years, 27 women [60.0%]). The highest-ranked ALT predictors were septation thickness (gain ratio merit [GRM] 0.623 ± 0.025, p = 0.0055), intra- and peritumoral STIR signal discrepancy (GRM 0.458 ± 0.046, p < 0.0001), orthogonal diameter (GRM 0.554 ± 0.188, p = 0.0013), contrast enhancement (GRM 0.235 ± 0.015, p = 0.0010) and maximum diameter (GRM 0.221 ± 0.075, p = 0.0009). The quantitative features did not provide a significant discriminatory value. The highest-ranked predictors were used to generate a five-tiered score for the identification of ALTs (correct classification rate 95.7% at a cut-off of three positive items, sensitivity 100.0%, specificity 94.9%, likelihood ratio 19.5). Conclusions: Several single MRI features have a substantial diagnostic value in the identification of ALT, yet a multiparametric approach by a simple combination algorithm may support radiologists in the identification of lipomatous tumors in need for further histological assessment.

Giant retroperitoneal liposarcoma measuring 27 × 29 × 36 cm: a case report

Retroperitoneal tumors are rare neoplasms that can reach great dimensions due to a slow growth pattern. Although these tumors rarely metastasize, they have a great risk of recurrence, and majority of times these lesions are a challenge for the surgeon. We report the case of a 63-year-old woman who presented with symptoms of large bowel obstruction and was diagnosed with a large heterogenous mass located in the retroperitoneal space. The fine needle biopsy revealed the histology of liposarcoma. The purpose of this article is to report our approach in management of this kind of tumor. Tumor size (27.1 × 29.1 × 36.1 cm) and involvement to the adjacent organs was a challenge for us in order to reach safe oncological margins. In these cases, the risk of recurrence is high; therefore, the patient should be screened at 6, 12 and 24 months post procedure. Chemotherapy or radiotherapy for this tumor is not yet defined, and if operable, surgery is the treatment of choice.

Genetic Alterations and Deregulation of Hippo Pathway as a Pathogenetic Mechanism in Bone and Soft Tissue Sarcoma

The Hippo pathway is an evolutionarily conserved modulator of developmental biology with a key role in tissue and organ size regulation under homeostatic conditions. Like other signaling pathways with a significant role in embryonic development, the deregulation of Hippo signaling contributes to oncogenesis. Central to the Hippo pathway is a conserved cascade of adaptor proteins and inhibitory kinases that converge and regulate the activity of the oncoproteins YAP and TAZ, the final transducers of the pathway. Elevated levels and aberrant activation of YAP and TAZ have been described in many cancers. Though most of the studies describe their pervasive activation in epithelial neoplasms, there is increasing evidence pointing out its relevance in mesenchymal malignancies as well. Interestingly, somatic or germline mutations in genes of the Hippo pathway are scarce compared to other signaling pathways that are frequently disrupted in cancer. However, in the case of sarcomas, several examples of genetic alteration of Hippo members, including gene fusions, have been described during the last few years. Here, we review the current knowledge of Hippo pathway implication in sarcoma, describing mechanistic hints recently reported in specific histological entities and how these alterations represent an opportunity for targeted therapy in this heterogeneous group of neoplasm.

Thyroid liposarcoma: a case report

Objectives

Thyroid liposarcoma is a rare tumor. Its low prevalence accounts for the scarcity of data in the literature, which consists mostly of small studies and case reports.

Case presentation

We present the case of a 60 years old male with no past medical or past surgical history and presented with neck discomfort and a large left thyroid nodule. Thyroid ultrasound and CT scan were performed and confirmed the existence of a thyroid nodule most probably inside the left inferior thyroid lobe. In the posterior mediastinum, two fatty formations were found. To complete, an MRI was performed, showing a mixed lesion, of the lower neck and upper chest. The patient underwent an extended resection which consisted of an en bloc resection of the lesion (left thyroid lobectomy and isthmus resection) by an anterior transverse cervical incision and a sternotomy. Tracheal and laryngeal shaving and esophageal shaving with resection of the esophageal muscularis was performed as well. The pathological evaluation of the specimen showed a grade II dedifferentiated liposarcoma with an inflammatory component.

Conclusions

Thyroid liposarcoma is a rare lesion of the thyroid. Its management requires an exhaustive workup followed by an en bloc resection of the lesion. Depending on the histology, postoperative radiation therapy may or may not be necessary.

Survival of a patient with multiple-recurrent giant retroperitoneal dedifferentiated liposarcoma for 15 years: A case report

Background

Retroperitoneal liposarcoma (RPLS) is a variety of soft tissue sarcoma that originates from mesenchymal cells. A tumor measuring greater than 30 cm is called a “giant liposarcoma.” A part of the neoplasm tends to grow in size, recur locally, or metastasize distantly. In those with such a condition, long-term survival is uncommon. Therefore, it is necessary to present a uniform and optimized program to improve the prognosis.

Methods

By successfully treating a multiple-recurrent giant retroperitoneal dedifferentiated liposarcoma (RP DDLPS) in July 2010, we hope to devise more comprehensive strategies to improve diagnosis, therapy, and outcome.

Results

In July 2010, we thoroughly resected a giant multifocal RPLS with a concomitant part of the gastric wall. The histopathological examination revealed a high-grade (grade III) dedifferentiated liposarcoma. The patient was discharged uneventfully on the 15th postoperative day. She relapsed after 16 months and needed another complete excision. After 9 months, she died after the fourth recidive. The patient had experienced four recurrences and underwent operations with 15 years of follow-up.

Conclusions

The above demonstrates that we were able to successfully treat the multirecurrent giant RPLS, despite the patient’s poor medical condition, with meticulous management. Moreover, this indicates that long-term survival could be achieved for high-grade RP DDLPS.

[Pleomorphic liposarcoma arising in an unusual site. A case report]

Liposarcomas are the most common group of malignant mesenchymal neoplasms. They usually occur in the extremities and the retroperitoneum and only rarely in the intestine. We report the case of a 75-year-old man presenting with severe anaemia. A CAT scan revealed a 5cm thickening of the jejunal loop, arousing the suspicion of a neoplasm. A partial resection of the small intestine was performed. Macroscopy showed a 12×6cm ulcerated, polypoid mass. Microscopically, a well circumscribed, ulcerated tumour was seen, which had well-defined margins with the surrounding normal mucosa. It consisted of pleomorphic lipoblasts within a sarcomatous background. Very few cases of intestinal liposarcomas have been published and the majority report well-differentiated or undifferentiated liposarcomas. We present a case of a pleomorphic liposarcoma of the small intestine, which is an unusual location and emphases the importance of a comprehensive differential diagnosis.

Prognosis and survival of patients diagnosed with well-differentiated and dedifferentiated retroperitoneal liposarcoma

OBJECTIVES

The main objective is to establish the overall survival and disease-free survival profiles regarding the patients with retroperitoneal liposarcoma, making a comparison based on the well-differentiated and dedifferentiated histological subtypes. The secondary objectives are to descriptively analyze the clinical characteristics of said patients and to identify and analyze other independent variables that might modify these survival profiles significantly.

METHODS

An observational and analytical study was performed using a retrospective historical cohort that was followed prospectively. The inclusion criteria consisted of: the procedure of liposarcoma located in the retroperitoneum, the well-differentiated and dedifferentiated histological subtypes, between January of 2002 and May of 2019. As a result, 32 patients took part in this study's sample. Kaplan-Meier estimator was used to summarise the results and log-rank test was used in the comparative analysis.

RESULTS

The overall survival at 5 years was around 59%. No differences were found between the patients with a well-differentiated subtype compared to the dedifferentiated ones (p = 0.834). The disease-free survival at 2 years was 59% regarding the well-differentiated and 26% regarding the dedifferentiated, with these differences being statistically significant (p = 0.005). None of the other studied variables modified these survival profiles significantly.

CONCLUSIONS

Dedifferentiated retroperitoneal liposarcomas show less disease-free survival than well-differentiated liposarcomas. However, regarding overall survival no differences can be claimed.

Myxomatous Liposarcoma of the Mediastinum: A Review of the Literature

Myxomatous liposarcoma is an extremely rare type of mediastinal tumour that manifests in a manner comparable to other lung pathologies. Chest pain, shortness of breath, and dysphagia are the common presenting complaints. Radiological examinations or postoperative histological examinations provide the majority of the diagnostic evidence. The cornerstone of therapy consists of surgery and sometimes chemotherapy. Those who are afflicted have a better chance of experiencing favourable outcomes if they receive a diagnosis and treatment quickly.

Mediastinal Liposarcoma With Anterior and Posterior Mediastinal Involvement: A Thoracic Oncovascular Case Report

A 64-year-old patient presented with shortness of breath and chest pressure. The initial examination was unremarkable, and a chest X-ray revealed a large mediastinal mass. Computed tomography (CT) scan demonstrated a lobulated mediastinal mass involving the great vessels and mass effect on the trachea, esophagus, and heart. A CT-guided biopsy showed a monotonous, evenly spaced population of mature, normal-appearing adipocytes consistent with a well-differentiated lipoma-like liposarcoma/atypical lipomatous tumor. The patient underwent a median sternotomy with en bloc tumor resection without adjuvant chemoradiation. Three-year follow-up CT imaging shows no evidence of tumor recurrence.

Pleomorphic liposarcoma: A clinicopathologic study of 20 FNA cases

BACKGROUND

Pleomorphic liposarcoma (PLPS) is the least common but most aggressive of all forms of liposarcoma (LPS). Its diagnosis relies on the recognition of pleomorphic lipoblasts (PLBs), whose numbers vary considerably. Because few large fine-needle aspiration (FNA) biopsy studies exist, the authors review their experience with PLPS.

METHODS

The authors' cytopathology files were searched for PLPS with histopathologic verification. FNA biopsy smears were performed via standard techniques.

RESULTS

Twenty cases from 20 patients (male/female ratio, 2.3/1; age range, 22-77 years; mean age, 58 years) met the inclusion criteria. All had tissue confirmation. Biopsy sites included the following: thigh (11 [55%]), upper extremity (4 [20%]), axilla (2 [10%]), neck (1 [5%]), chest wall (1 [5%]), and mediastinum (1 [5%]). Aspirates were from primary (17 [85%]), locally recurrent (2 [10%]), and metastatic neoplasms (1 [5%]). The FNA diagnoses were PLPS (10 [50%]), myxofibrosarcoma (4 [20%]), LPS (2 [10%]), sarcoma (2 [10%]), and high-grade malignant neoplasm (2 [10%]). Smears showed thick cell clusters and dissociated single forms. Pleomorphic, epithelioid, and bizarre cell/nuclear shapes were common. PLBs were absent, rare, or unnoticed in 45%. In 25%, smears dominated by myxoid stroma were diagnosed as high-grade myxofibrosarcoma or myxoid LPS. Ancillary testing performed in 5 cases had limited diagnostic efficacy.

CONCLUSIONS

FNA biopsy of PLPS, although able to successfully recognize malignancy, suffers from a sampling bias due to an inability to capture or recognize PLBs in a significant proportion of cases secondary to the heterogeneous composition of this neoplasm.

Isolated pathologies of Tensor Fasciae Latae: Retrospective cohort analysis from a tertiary referral centre

INTRODUCTION

Tensor Fasciae Latae (TFL) and the iliotibial band (ITB) act as a single functional unit in maintaining pelvic stability whilst standing, walking, or running in human beings. The Tensor Fasciae Latae (TFL) muscle acts across the hip and the knee joint. Consequently, though its pathologies traditionally present with lateral hip pain, identifying the precise clinical diagnosis can be a challenge.

PATIENTS AND METHODS

A retrospective search for the keyword 'Tensor Fasciae Latae'/iliotibial band (ITB) was performed of our Radiology Information System (RIS) and Picture Archiving and Communication System (PACS), Computerised Radiology Information System (CRIS) at our tertiary orthopaedic referral centre of a for orthopaedic oncology over a period of 13 years (2007-2020). Data was collected from RIS, oncology database and local histopathology laboratory records. Patient demographics, clinical characteristics, complementary imaging and clinical management outcome were documented.

RESULTS

We identified 35 patients with a mean age of 66 years (range 19-94 years). There were 18 female and 17 male patients. Lateral hip lump and pain were the most frequent clinical finding/presentation features. A variety of pathologies such as benign and malignant tumours, including vascular and tumour mimic lesions involving the TFL muscle were identified. Atrophy and pseudohypertrophy of TFL was the commonest pathology found; accounting for two thirds of the cases.

CONCLUSION

Tensor Fasciae Latae (TFL) can be afflicted with a broad spectrum of pathologies. Radiological imaging especially cross-sectional imaging modality is crucial in guiding appropriate patient management of TFL conditions. Our analysis suggests isolated TFL lesion are more likely to be benign conditions, presenting commonly as hip pain and swelling.

Primary duodenal dedifferentiated liposarcoma: A case report and literature review

BACKGROUND

Dedifferentiated liposarcoma (DDLPS) is an extremely rare neoplasm that exhibits various morphologies. The tumor is characterized by immunoreactivity to MDM2 and CDK4 and can be confirmed by detecting MDM2 amplification via fluorescence in situ hybridization (FISH). Herein, we report an unusual case of DDLPS arising from the duodenum.

CASE SUMMARY

A 64-year-old man presented with repeated abdominal pain and weight loss. Radiologic studies revealed a mass of the duodenum involving the pancreas. The patient was treated with pylorus-preserving pancreaticoduodenectomy. Histologically, the tumor showed a high-grade sarcoma. Immunohistochemistry demonstrated that the tumor cells were positive for MDM2 and CDK4 expression. MDM2 amplification was detected via FISH, leading to the final diagnosis of DDLPS. Following surgery, the patient was treated in the intensive care unit due to peritonitis, and died 60 d after surgery.

CONCLUSION

To the best of the authors’ knowledge, this is the first case of primary duodenal DDLPS in Korea and the third case in the English-language literature. Care must be taken not to misdiagnose DDLPS as another high-grade tumor. Liposarcoma should be in the differential diagnosis list.

Liposarcoma subtype recurrence and survival: A UK regional cohort study

BACKGROUND

Clinical outcome data in the United Kingdom, Europe, and the United States have yet to facilitate appropriately specific surveillance for liposarcoma histological subtypes, despite being one of the most common soft tissue sarcomas. Therefore, this study aims to demonstrate histologic-specific differences in liposarcoma recurrence, disease progression, and survival and discuss the implications.

METHODS AND FINDINGS

This cohort study involves patients from a regional sarcoma service in the UK who have had a primary surgical excision of liposarcoma between October 2002 and September 2019. The median follow-up is five years. Confirmed histopathological diagnoses of liposarcoma (n = 193) are organised according to the World Health Organisation recognised subtypes: atypical lipomatous tumours (ALT), myxoid, pleomorphic, and dedifferentiated liposarcomas. In addition, retroperitoneal variants (n = 34) are included to illustrate the broader spectrum of phenotypes. The primary outcomes were local recurrence, distant disease progression, and disease-specific death, and compared using Kaplan-Meier analyses and tumour variables using Cox proportional hazard analyses. All three primary outcomes significantly differed (P < 0.0001, n = 193). There were no metastases or disease-specific death in patients with ALT (n = 92) and no metastases of their retroperitoneal counterparts (n = 17). Amongst the metastasising cases of rarer subtypes, there were pulmonary spread of pleomorphic (8/9, n = 20), dedifferentiated (4/5, n = 18), and myxoid (2/3, n = 29) liposarcomas.

CONCLUSION

An absence of metastases of ALT should be considered alongside global evidence. Surveillance protocols could better differentiate between these subtypes and, in doing so, save patients a considerable amount of irradiation, time, fear, and anxiety.

A scoring system combining clinical, radiological, and histopathological examinations for differential diagnosis between lipoma and atypical lipomatous tumor/well-differentiated liposarcoma

This study evaluated the diagnostic accuracy of clinical, radiological, and histopathological examinations for differential diagnosis between atypical lipomatous tumor (ALT)/well-differentiated liposarcoma (WDLS) and lipoma, and aimed to develop a new combined scoring system for the preoperative diagnosis of ALT/WDLS. Eighty-nine lipomas and 56 ALT/WDLS were included and their clinical characteristics, magnetic resonance imaging (MRI) findings, histological findings by hematoxylin and eosin (HE) staining were investigated. Then, univariate and multivariate logistic regression analyses were performed for the findings, and a combined scoring system consisted of predictive factors of ALT/WDLS was developed. The univariate and multivariate logistic regression analyses revealed that tumor location (lower extremity), deep site, size (> 11 cm), thick septa (> 2 mm), enhancement of septa or nodular lesions, and lipoblasts were significantly different for the diagnosis of ALT/WDLS. We developed a combined scoring system based on the six predictive factors (total 0-16 points, the cutoff was 9 points). The area under the curve was 0.945, and sensitivity was 87.6% and specificity was 91.1% by the receiver operating characteristics curve. This combined scoring system does not require special equipment and reagents such as fluorescence in situ hybridization (FISH), and anyone can use it easily in many medical institutions with high diagnostic accuracy.

Dedifferentiated liposarcoma of small bowel mesentery: a rare case report

Liposarcoma is a common occurrence over retroperitoneum. However, dedifferentiated liposarcoma is an uncommon variety affecting the small bowel mesentery, making it a rarity. We report a case of 56-year-old male presented with the lump in the abdomen. Computed tomography abdomen revealed well-defined space-occupying lesion. Laparotomy was done and mass was excised along with segment of ileum to achieve negative margin. Histopathology and immunohistochemical study helped in determining mass to be dedifferentiated liposarcoma of mesentery. Therefore, liposarcoma should be considered in differential diagnosis of abdominal mesenchymal tumors. Surgical resection to achieve negative margin is the mainstay of treatment for mesenteric liposarcomas.

Expression of CTAG1B clone EPR13780 versus DDIT3 gene rearrangement distinguishes myxoid liposarcoma from its mimics with detection of novel DDIT3 gene copy number variations

Myxoid liposarcoma (MLPS) has different patterns that are often difficult to distinguish from other soft tissue lesions. MLPS is characterized by a reciprocal translocation involving the DNA Damage Inducible Transcript 3 gene (DDIT3) that can be detected using fluorescent in situ hybridization (FISH). Recently, the marker for cancer testis antigen 1b (CTAG1B) was found to be expressed in MLPS. The aim of the present study was to assess the potential use immunohistochemistry (IHC) for CTAG1B expression and DDIT3 rearrangement to diagnose MLPS and distinguish it from similar lesions. Out of 29 cases including MLPS and its mimics, CTAG1B was expressed in 92.86% of cases of MLPS and 20% of its mimics. DDIT3 rearrangement was 100% sensitive and 92.86% specific in distinguishing MLPS from its mimics. The DDIT3 rearrangement was found to be more sensitive but less specific than cytoplasmic expression of CTAG1B marker. DDIT3 polysomy and amplification were detected in some cases. Therefore, both CTAG1B expression and FISH for DDIT3 gene can be used to distinguish MLPS from similar tumors. The use of both immunohistochemistry for CTAG1B in addition to DDIT3 gene rearrangement detection by FISH was more specific than using either of them alone. However, the DDIT3 gene rearrangement alone was the most sensitive test for distinguishing MLPS from its mimics.

Liposarcoma of the chest wall mimicking a breast mass in a man: a case report

We report a rare case of dedifferentiated liposarcoma in a man. A 60-year-old male patient presented with a left mass involving the whole breast area, with no lymph node enlargement, growing during a one-year-period. Imaging studies revealed a fat-containing mixed-density mass apparently associated with the pectoralis major muscle. A core biopsy was performed that yielded a diagnosis of a well-differentiated liposarcoma. Further tests to check for metastases were ordered and no distant disease was found. Left mastectomy with en bloc resection of the pectoralis major muscle was performed. The pathologic diagnosis revealed a high-grade dedifferentiated liposarcoma with extensive necrosis. This tumor type is primarily described in the retroperitoneum and extremities. We report an unusual presentation of a liposarcoma mimicking a breast mass.

Undifferentiated and dedifferentiated soft tissue neoplasms: Immunohistochemical surrogates for differential diagnosis

Undifferentiated soft tissue sarcomas (USTS) are described in the current World Health Organization Classification of Soft Tissue and Bone Tumours as those showing no identifiable line of differentiation when analyzed by presently available technologies. This is a markedly heterogeneous group, and the diagnosis of USTS remains one of exclusion. USTS can be divided into four morphologic subgroups: pleomorphic, spindle cell, round cell and epithelioid undifferentiated sarcomas, with this combined group accounting for up to 20% of all soft tissue sarcomas. As molecular advances enable the stratification of emerging genetic subsets within USTS, particularly within undifferentiated round cell sarcomas, other groups, particularly the category of undifferentiated pleomorphic sarcomas (UPS), still remain difficult to substratify and represent heterogeneous collections of neoplasms often representing the common morphologic endpoints of a variety of malignant tumors of various (mesenchymal and non-mesenchymal) lineages. However, recent molecular developments have also enabled the identification and correct classification of many tumors from various lines of differentiation that would previously have been bracketed under 'UPS'. This includes pleomorphic neoplasms and dedifferentiated neoplasms (the latter typically manifesting with an undifferentiated pleomorphic morphology) of mesenchymal (e.g. solitary fibrous tumor and gastrointestinal stromal tumor) and non-mesenchymal (e.g. melanoma and carcinoma) origin. The precise categorization of 'pleomorphic' or 'undifferentiated' neoplasms is critical for prognostication, as, for example, dedifferentiated liposarcoma typically behaves less aggressively than other pleomorphic sarcomas, and for management, including the potential for targeted therapies based on underlying recurrent molecular features. In this review we focus on undifferentiated and dedifferentiated pleomorphic and spindle cell neoplasms, summarizing their key genetic, morphologic and immunophenotypic features in the routine diagnostic setting, and the use of immunohistochemistry in their principal differential diagnosis, and highlight new developments and entities in the group of undifferentiated and dedifferentiated soft tissue sarcomas.

Prognosis and survival of patients diagnosed with well-differentiated and dedifferentiated retroperitoneal liposarcoma

OBJECTIVES

The main objective is to establish the overall survival and disease-free survival profiles regarding the patients with retroperitoneal liposarcoma, making a comparison based on the well-differentiated and dedifferentiated histological subtypes. The secondary objectives are to descriptively analyze the clinical characteristics of said patients and to identify and analyze other independent variables that might modify these survival profiles significantly.

METHODS

An observational and analytical study was performed using a retrospective historical cohort that was followed prospectively. The inclusion criteria consisted of: the procedure of liposarcoma located in the retroperitoneum, the well-differentiated and dedifferentiated histological subtypes, between January 2002 and May 2019. As a result, 32 patients took part in this study's sample. Kaplan-Meier estimator was used to summarize the results and log-rank test was used in the comparative analysis.

RESULTS

The overall survival at 5 years was around 59%. No differences were found between the patients with a well-differentiated subtype compared to the dedifferentiated ones (p=0.834). The disease-free survival at 2 years was 59% regarding the well-differentiated and 26% regarding the dedifferentiated, with these differences being statistically significant (p=0.005). None of the other studied variables modified these survival profiles significantly.

CONCLUSIONS

Dedifferentiated retroperitoneal liposarcomas show less disease-free survival than well-differentiated liposarcomas. However, regarding overall survival no differences can be claimed.

Cerebellar metastasis of a Liposarcoma: Case report and literature review

Background:

Liposarcoma (LPS) is a rare type of tumor; they come from the adipose tissue. It is the most common type of soft-tissue sarcoma. Every type of LPS has morphological features, immunophenotypic, and molecular pathogenesis characteristics of their own. In this case, we are going to report a cerebellar metastatic disease from a well-differentiated liposarcoma (WDL) with pleomorphic component, not found in our literature research.

Case Description:

A 72-year-old woman with progressive pain and inflammation in the left knee with functional limitation when climbing stairs. MRI shows a tumor in the vastus medialis of the left thigh. Pathology result was pleomorphic and WDL, Stage III and negative for MDM2 and CDK4. Extension study was carried out, finding nodular lesion in the right cerebellar hemisphere with mass effect and partial obliteration of the fourth ventricle, suspicious of distant disease.

Conclusion:

Cerebellar metastasis of LPS is uncommon; there are only a few cases reports with the literature reviews describing orbital or skull base metastases, but not in the cerebellum. Our case allows us to remember that neurological symptoms, no matter how subtle, in patients diagnosed with LPS, a secondary affectation of the central nervous system must be ruled out, even though it is a rare location. The findings of distant disease in LPSs, allow planning oncological treatment options and targeted radiotherapeutic.

EWSR1-The Most Common Rearranged Gene in Soft Tissue Lesions, Which Also Occurs in Different Bone Lesions: An Updated Review

EWSR1 belongs to the FET family of RNA-binding proteins including also Fused in Sarcoma (FUS), and TATA-box binding protein Associated Factor 15 (TAF15). As consequence of the multifunctional role of EWSR1 leading to a high frequency of transcription of the chromosomal region where the gene is located, EWSR1 is exposed to aberrations such as rearrangements. Consecutive binding to other genes leads to chimeric proteins inducing oncogenesis. The other TET family members are homologous. With the advent of widely used modern molecular techniques during the last decades, it has become obvious that EWSR1 is involved in the development of diverse benign and malignant tumors with mesenchymal, neuroectodermal, and epithelial/myoepithelial features. As oncogenic transformation mediated by EWSR1-fusion proteins leads to such diverse tumor types, there must be a selection on the multipotent stem cell level. In this review, we will focus on the wide variety of soft tissue and bone entities, including benign and malignant lesions, harboring EWSR1 rearrangement. Fusion gene analysis is the diagnostic gold standard in most of these tumors. We present clinicopathologic, immunohistochemical, and molecular features and discuss differential diagnoses.

Analysis of Differentiation Changes and Outcomes at Time of First Recurrence of Retroperitoneal Liposarcoma by Transatlantic Australasian Retroperitoneal Sarcoma Working Group (TARPSWG)

BACKGROUND

Local recurrence following resection of retroperitoneal liposarcoma (RLPS) is common. Well-differentiated (WD) and dedifferentiated (DD) RLPS are distinct entities with differing outcomes. A few reports suggest that WDLPS can recur as DDLPS and that DDLPS can recur as WDLPS. This study evaluates whether this change in differentiation from the primary tumor to the first local recurrence impacts long-term outcomes.

METHODS

Retrospective review from 22 sarcoma centers identified consecutive patients who underwent resection for a first locally recurrent RLPS from January 2002 to December 2011. Outcomes measured included overall survival, local recurrence, and distant metastasis.

RESULTS

A total of 421 RPLS patients were identified. Of the 230 patients with primary DDLPS, 34 (15%) presented WDLPS upon recurrence (DD → WD); and of the 191 patients with primary WDLPS, 54 (28%) presented DDLPS upon recurrence (WD → DD). The 6-year overall survival probabilities (95% CI) for DD → DD, DD → WD, WD → WD, and WD → DD were 40% (32-48%), 73% (58-92%), 76% (68-85%), and 56% (43-73%) (p < 0.001), respectively. The 6-year second local recurrence incidence was 66% (59-73%), 63% (48-82%), 66% (57-76%), and 77% (66-90%), respectively. The 6-year distant metastasis incidence was 13% (9-19%), 3% (0.4-22%), 5% (2-11%), and 4% (1-16%), respectively. On multivariable analysis, DD → WD was associated with improved overall survival when compared with DD → DD (p < 0.001). Moreover, WD → DD was associated with a higher risk of LR (p = 0.025) CONCLUSION: A change in RLPS differentiation from primary tumor to first local recurrence appears to impact survival. These findings may be useful in counseling patients on their prognosis and subsequent management.

The Rapidly Expanding Group of RB1-Deleted Soft Tissue Tumors: An Updated Review

The classification of soft tissue tumors has evolved considerably in the last decade, largely due to advances in understanding the pathogenetic basis of many of these, sometimes rare, tumors. Deletion of Retinoblastoma 1 (RB1), a well-known tumor suppressor gene, has been implicated in the tumorigenesis of a particular group of soft tissue neoplasms. This group of so-called “RB1-deleted soft tissue tumors” has been rapidly expanding in recent years, currently consisting of spindle cell/pleomorphic lipoma, atypical spindle cell/pleomorphic lipomatous tumor, pleomorphic liposarcoma, myofibroblastoma, cellular angiofibroma, and acral fibromyxoma. Most of these neoplasms, except pleomorphic liposarcoma, are considered benign entities and are mainly described in the older adult population. This article will review the currently known morphological, immunohistochemical, and molecular features of this heterogeneous group of mesenchymal tumors with an emphasis on differential diagnosis.

Trabectedin for Patients with Advanced Soft Tissue Sarcoma: A Non-Interventional, Retrospective, Multicenter Study of the Italian Sarcoma Group

Simple Summary

Active therapeutic options in advanced soft tissue sarcoma (STS), able to induce durable objective responses, are scarce beyond first-line chemotherapy. Thus, new strategies and optimal sequencing in the treatment algorithm for sarcoma represents an utmost clinical challenge. This non-interventional, retrospective, multicenter study of the Italian sarcoma group aimed to provide insights of the real-world efficacy, toxicity, and management of patients with advanced STS treated with trabectedin in clinical practice across Italy. Our findings on 512 pretreated metastatic patients with multiple sarcoma histologies in terms of time-to-event outcomes (median progression-free survival of 5.1 months and median overall survival of 21.6 months) confirm the activity of this regimen in a real-life setting with a manageable and well-characterized safety profile. Our study has corroborated that in real-life clinical practice, trabectedin is mostly given as a second-line treatment to patients with a good performance status and high-grade, metastatic leiomyosarcoma and liposarcoma.

Abstract

The Italian Sarcoma Group performed this retrospective analysis of patients with advanced soft tissue sarcoma, pretreated with ≥1 anthracycline-based treatment, and treated with trabectedin every three weeks. Primary endpoint was to describe real-life use of trabectedin across Italy. Secondary endpoints included objective response rate (ORR) and safety. Overall, 512 patients from 20 Italian centers were evaluated. Leiomyosarcoma (37.7%)/liposarcoma (30.3%) were the most prevalent histological types (abbreviated as L-sarcoma). Patients received a median of four trabectedin cycles (range: 1–40), mostly as a second-line treatment (~60% of patients). The ORR was 13.7% superior (p < 0.0001) in patients with L-sarcoma compared with patients with non-L-sarcoma (16.6% vs. 9.0%). Median progression-free survival (PFS) was 5.1 months, whereas median overall survival (OS) was 21.6 months. Significantly better PFS and OS were observed in patients with L-sarcoma, those with objective responses and/or disease stabilization, treated in an early line and treated with reduced dose. Bone marrow toxicity (61.4%) and transaminase increases (21.9%) were the most common grade 3/4 adverse events. The results of this real-life study suggest that trabectedin is an active treatment, which is mostly given as a second-line treatment to patients with a good performance status and high-grade, metastatic L-sarcoma (clinical trial information: NCT02793050).

Myxoid Liposarcoma Metastasizing to the Parotid Gland

Localization of metastases into the parotid gland is a very uncommon event. Usually they arise from primary tumors located in the head and neck, mainly melanoma or epidermoid carcinoma of the skin, while other histotypes, from others anatomical districts, hardly have a metastatic spread to the parotid. Myxoid liposarcoma (MLS) is a rare malignant tumor of the soft tissue that mainly occurs in the extremities, representing the second most common subtype of liposarcoma. Although it is typical for liposarcomas to metastasize to the lungs, it is known that MLS can spread also to extra pulmonary sites. The authors report a case of myxoid liposarcoma of the left thigh in a 64-year-old man, with an unusual metastatic double presentation to the contralateral forearm first and to the parotid gland then. MLS with metastatic disease to the parotid gland is an extremely rare event with very few cases reported in the English literature.

Diagnostic concordance between ultrasound-guided core needle biopsy and surgical resection specimens for histological grading of extremity and trunk soft tissue sarcoma

OBJECTIVE

Determination of accurate histological grade impacts on management for soft tissue sarcomas (STSs). Although ultrasound-guided core needle biopsy (US-CNB) accurately establishes tumour subtype compared with surgical specimens, the concordance for tumour grade is uncertain. The aim of this study was to assess the concordance between US-CNB and surgical resection specimens for tumour grade in trunk and extremity STS.

MATERIALS AND METHODS

Retrospective review of consecutive patients presenting with extremity/trunk STS. Data collected included patient age, gender, lesion location, US-CNB diagnosis and grade, and surgical histology and grade. The histological diagnosis and tumour grade from US-CNB was compared with surgical resection histology.

RESULTS

A total of 118 patients were included, 76 males and 42 females with a mean age of 54 years (range 10 months-90 years old). STS size ranged from 26 to 350 mm (mean 89.5 mm). All US-CNB procedures were performed with a 14G biopsy needle with a mean number of 5 passes. First US-CNB was diagnostic for STS in all patients, and provided adequate tissue for tumour grading in all but one patient. Histological tumour subtype on US-CNB matched surgical specimens in all cases, with 25 (21.2%) STS being low grade and 93 (78.8%) high grade. The concordance for tumour grade was 96.6%, with no difference between low- and high-grade STSs (p > 0.05). The 4 cases of mismatch were considered low grade on US-CNB, but subsequently high grade on surgical resection.

CONCLUSION

US-CNB of STS can reliably predict histological tumour grade compared with surgical resection specimens, thus allowing confident treatment decisions to be made.

A Rapid and Cost-Effective Gene Expression Assay for the Diagnosis of Well-Differentiated and Dedifferentiated Liposarcomas

Histologic examination neither reliably distinguishes benign lipomas from atypical lipomatous tumor/well-differentiated liposarcoma, nor dedifferentiated liposarcoma from other pleomorphic sarcomas, entities with different prognoses and management. Molecular confirmation of pathognomonic 12q13-15 amplifications leading to MDM2 overexpression is a diagnostic gold standard. Currently the most commonly used assay for this purpose is fluorescence in situ hybridization (FISH), but this is labor intensive. This study assessed whether newer NanoString-based technology could allow for more rapid and cost-efficient diagnosis of liposarcomas on standard formalin-fixed tissues through gene expression. Leveraging large-scale transcriptome data from The Cancer Genome Atlas, 20 genes were identified, most from the 12q13-15 amplicon, that distinguish dedifferentiated liposarcoma from other sarcomas and can be measured within a single NanoString assay. Using 21 cases of histologically ambiguous low-grade adipocytic tumors with available MDM2 amplification status, a machine learning-based analytical pipeline was built that assigns a given sample as negative or positive for liposarcoma based on quantitative gene expression. The effectiveness of the assay was validated on an independent set of 100 sarcoma samples (including 40 incident prospective cases), where histologic examination was considered insufficient for clinical diagnosis. The NanoString assay had a 93% technical success rate, and an accuracy of 97.8% versus an MDM2 amplification FISH gold standard. NanoString had a considerably faster turnaround time and was cheaper than FISH.

Value of clinical, ultrasonographic and MRI signs as diagnostic differentiators of non-benign lipomatous tumours

Suspicion of malignant change within a lipoma is a common and increasing workload within the UK Sarcoma multidisciplinary team (MDT) network, and a source of considerable patient anxiety. Currently, there is no lipoma-specific data, with regard to which clinical or radiographic features predict non-benign histology, or calculate an odds-ratio specific to a lipomatous lesion being non-benign. We performed a 9-year, double-blind, unmatched cohort study, comparing post-operative histology outcomes (benign versus non-benign) versus 15 signs across three domains: Clinical (size of tumour, depth, growth noticed by patient, previous lipoma, patient felt pain), Ultrasonographic (size, depth, vascularity, heterogenous features, septae) and MRI (size, depth, vascularity, heterogenous features, septae, complete fat signal suppression). Receiver operating characteristic (ROC) analysis, odds ratios and binary logistic regression analysis was performed double-blind. When each sign is considered independently, (ROC analysis, followed by binary logistic regression) only Ultrasound depth is a significant predictor (p = 0.044) of a histologically non-benign lipoma. Ultrasonographically determined vascularity and septation were not statistically significant predictors. None of the clinical signs were statistically significant (p > 0.05). Of the MRI signs none was statistically significant (p > 0.05). However, heterogeneous MRI features fared better than MRI depth. Ultrasound signs (Pseudo R-Square = 0.105) are more predictive of the post-operation histology outcome than Clinical signs (Pseudo R-Square = 0.082) or MRI tests (Pseudo R-Square = 0.052) Ultrasound and Clinical tests combined (Pseudo R-Square = 0.147) are more predictive of the post-operation histology outcome than MRI tests (Pseudo R-Square = 0.052). This work challenges the traditional perception of “red-flag” signs when applied to lipomatous tumours. We provide accurate data upon which an informed choice can be made, and provides a robust bases for expedited risk/benefit. The importance of an experienced and cohesive MDT network is emphasised.

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

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

[Retroperitoneal dedifferentiated liposarcomas: semi-quantitative assessment of the dedifferentiated component and prognosis]

OBJECTIVE

To evaluate the impact of malignancy grade and the proportion of the dedifferentiated component (DC) in retroperitoneal dedifferentiated liposarcomas (DDLS) on the course and prognosis of the disease.

MATERIAL AND METHODS

The retrospective study enrolled 74 patients with primary retroperitoneal DDLS who underwent radical surgical treatment in the N.N. Blokhin National Medical Research Center of Oncology, Ministry of Health of Russia. Histological surgery specimens from all cases of DDLS were reexamined and reclassified. According to malignancy grades and the proportion of the dedifferentiated component in the tumor, the patients were divided into the comparison groups included in the intergroup analysis of overall and relapse-free survival (OS and RFS) rates. The authors also analyzed the relationship between the proportion of the dedifferentiated component in DDLS and the frequency of adjacent organ invasion.

RESULTS

Patients with a more than 15% dedifferentiated component had significantly lower OS rates than those with a less than 15% one (p=0.0001; log-rank test). The median OS in the DDLS group with a less than 15% dedifferentiated component was 91 months (95% CI, 82-100); that in the DDLS group with a more than 15% dedifferentiated component was 29 months (95% CI 17-41). The 5-year overall survival rates in the groups with less than 15% and more than 15% dedifferentiated components were 69% and 2%, respectively. The group with a more than 15% dedifferentiated component had significantly lower RFS rates than that with a less than 15% one (p=0.0001; log-rank test). In the DDLS groups with less than 15% and more than 15% dedifferentiated components, the median RFS rates were 25 months (95% CI 23-27) and 13 months (95% CI 8-18), respectively. In these groups, the 2-year RFS rates were equal to 50% and 9%, respectively. In the DDLS groups with less than 15% and more than 15% dedifferentiated components, pathologically confirmed invasion into the adjacent organs was observed in 32% and 63% of cases, respectively. There were no statistically significant differences in the OS and RFS of patients with DDLS according to tumor grade (p=0.069; p=0.102).

CONCLUSION

This investigation suggests that DDLS have a more aggressive course with an increasing proportion of the dedifferentiated component in the tumor. Considering the histological variability in the dedifferentiated component, which is demonstrated in the research and scientific literature, as well as lack of a prognostic impact of histological grade, the authors believe that semi-quantitative assessment of the proportion of the dedifferentiated component in DDLS is able to serve as a simple and efficient morphological marker for the course of the disease and prognosis in retroperitoneal DDLS.

Giant retroperitoneal liposarcoma with a maximum diameter of 37 cm: a case report and review of literature

Retroperitoneal liposarcoma is a rare malignancy derived from adipocytes. They can grow to large sizes before inducing clinical symptoms. Giant retroperitoneal liposarcoma with a diameter over 30 centimeters is extremely rare. So far, only 13 cases of giant retroperitoneal liposarcoma with a diameter greater than 30 cm have been reported. There is very little experience in the treatment of these bulky tumors. Herein, we report a 65-year-old male patient diagnosed with giant retroperitoneal liposarcoma. The patient underwent successful complete surgical resection. The tumor was found to occupy almost the entire abdominal cavity, measuring 37.0 cm × 32.0 cm × 26.5 cm in size and 21.0 kg in weight. Histopathological analysis indicated a grade I, well-differentiated liposarcoma. The patient was discharged uneventfully, and no sign of recurrence was observed at 12-month follow-up. Moreover, we reviewed 13 literatures in English published on PubMed database regarding retroperitoneal liposarcoma greater than 30 cm in diameter. The analysis suggests that size alone should not be considered as a contraindication to surgical resection. Combined resection of adjacent organs is necessary if local invasion is confirmed. The role of adjuvant radio or chemotherapy remains controversial. Thorough evaluation on the extent of resection should be made to minimize post-surgery decline in quality of life.

Mediastinal liposarcoma masquerading as penetrating aortic ulcer in the descending aorta: a case report

A 56-year-old woman with a history of hypertension and cerebral infarction was admitted to the hospital complaining of progressive and severe chest pain for 1 day. CT scan revealed a descending penetrating ulcer. Accordingly, she underwent an uneventful endovascular repair with a thoracic endograft. One month later the patient presented to our clinic with chest and back pain again. The contrast CT indicated that the periaortic mass grew larger, which interpreted as hematoma resulting from endoleak. But no endoleak was found by angiography. CT-guided needle biopsy was carried out, the histology of the mass revealed a pleomorphic liposarcoma. Liposarcomas are malignant fat-containing tumors derived from mesenchymal cells that typically occur in the extremities and retroperitoneum, mediastinal liposarcoma account for less than 1% in mediastinal malignancies; pleomorphic liposarcoma is the least common liposarcomas. Cases of liposarcoma invading vascular system are seldom, to our knowledge, it is the first case of mediastinal pleomorphic liposarcoma invaded the descending aorta. It is worth mentioning that in the modern endovascular era, the majority of aortic diseases are being repaired by endovascular techniques. When patients with growing periaortic mass post endovascular repair and endograft-related causes have been excluded, the rare possibility of mediastinal liposarcoma should arise as a differential diagnosis. Promptly CT-guided biopsy help establish an early diagnosis.

Establishment and characterization of NCC-DDLPS1-C1: a novel patient-derived cell line of dedifferentiated liposarcoma

Dedifferentiated liposarcoma (DDLPS) is one of the four subtypes of liposarcomas; it is characterized by the amplification of the 12q13-15 region, which includes MDM2 and CDK4 genes. DDLPS has an extremely high local recurrence rate and is refractory to chemotherapy and radiation, which leads to poor prognosis. Therefore, a novel therapeutic strategy should be urgently established for improving the prognosis of DDLPS. Although patient-derived cell lines are important tools for basic research, there are no DDLPS cell lines available from public cell banks. Here, we report the establishment of a novel DDLPS cell line. Using the surgically resected tumor tissue from a patient with DDLPS, we established a cell line and named it NCC-DDLPS1-C1. The NCC-DDLPS1-C1 cells contained 12q13-15, 1p32, and 1q23 amplicons and highly expressed MDM2 and CDK4 proteins. NCC-DDLPS-C1 cells exhibited constant growth, spheroid formation, aggressive invasion, and tumorigenesis in mice. By screening a drug library, we identified that the proteasome inhibitor, bortezomib, had inhibitory effects on the proliferation of NCC-DDLPS1-C1 cells. We concluded that the NCC-DDLPS1-C1 cell line may serve as a useful tool for basic and pre-clinical studies of DDLPS.

Cardiac metastases from primary myxoid liposarcoma of the thigh: a case report

BACKGROUND

Myxoid liposarcoma is well known to have an unusual proclivity for extrapulmonary metastasis. However, cardiac metastasis of myxoid liposarcoma is very rare, even in patients with advanced disease.

CASE PRESENTATION

A 40-year-old man was diagnosed with myxoid liposarcoma of the right thigh and treated with wide resection. Two years after the surgery, a low-density area in the left ventricle was found on follow-up chest computed tomography, and was suspected of being metastatic disease. He underwent surgical treatment, and the lesion was pathologically confirmed as metastasis of myxoid liposarcoma. Fifteen months later, he complained of slight dyspnea and developed metastatic disease in the right atrium. He was treated with surgical excision, followed by radiotherapy. Although there was no recurrence in the heart since the second cardiac metastasectomy, multiple metastases occurred in the abdominal cavity, lungs, and muscles. He finally died of the disease 2 years after the second cardiac metastasectomy.

CONCLUSION

We experienced a case of primary myxoid liposarcoma in the thigh, accompanied by ectopic and metachronous cardiac metastases. Although this condition is rare, we should follow-up patients with myxoid liposarcoma, considering the possibility of cardiac metastasis.

Hypofractionated Radiotherapy in Locally Advanced Myxoid Liposarcomas of Extremities or Trunk Wall: Results of a Single-Arm Prospective Clinical Trial

Introduction: Myxoid liposarcoma (MLPS) has been reported to be more radiosensitive compared with other soft tissue sarcomas. The main objective of the study was to assess the efficacy of hypofractionated radiotherapy (RT) in the preoperative setting in patients with locally advanced primary MLPS. Methods: Single-arm prospective exploratory clinical trial enrolled MLPS patients for preoperative 5 × 5 Gy RT with delayed surgery. The endpoints of the study were the rate of early wound healing complications and 5-year local control rate. Results: 29 patients (pts) were included, all had tumors located on the lower limb. The median maximum size of the tumor was 13 cm (IQR 10–15 cm). Early RT tolerance was good. Postoperative wound complications occurred in 11 pts (37.9%), late complications concerned 13.8% of patients. A total of 27 patients were included for the efficacy analyses. The pathological features of response to RT were detected in all analyzed surgical specimens. In 25 patients R0 margins were achieved, two patients had an R1 resection. None of the patients had local recurrence. Conclusion: Preoperative hypofractionated RT with a prolonged gap between RT and surgery is a feasible method of the management of MLPS, providing a good local control and low rates of treatment toxicity.

Diagnostic Utility and Limitations of Immunohistochemistry of p16, CDK4, and MDM2 and Automated Dual-color In Situ Hybridization of MDM2 for the Diagnosis of Challenging Cases of Dedifferentiated Liposarcoma

The diagnosis of dedifferentiated liposarcoma (DDLPS) is challenging when an atypical lipomatous tumor component is absent or obscure. To analyze the utility and limitations of ancillary techniques, we studied 11 cases of DDLPS in challenging conditions and 17 cases of nonlipogenic high-grade sarcomas with immunohistochemistry (IHC) for p16, CDK4, and MDM2 and automated dual-color in situ hybridization (DISH) for MDM2 amplification. All DDLPS specimens lacked clear lipogenic components and were immunoreactive for p16, CDK4, and MDM2. DISH analyses also revealed high-level amplification of MDM2 in all DDLPS. In contrast, among nonlipogenic sarcomas, p16, CDK4, and MDM2 were expressed in 8, 9, and 3 cases, respectively. MDM2 amplification was detected in 3 of 8 studied. The MDM2-amplified tumors were the same as the MDM2-immunoreactive tumors. After careful reevaluation of these 3 sarcomas, 2 were reclassified as DDLPS because small areas of lipogenic components were detected in the original specimens. The respective sensitivities and specificities of these markers were as follows: p16 IHC (100% and 60%), CDK4 IHC (100% and 53.3%), MDM2 IHC (100% and 93.3%), and MDM2 DISH (100% and 83.3%). The results of MDM2 IHC completely coincided with those of MDM2 DISH. The present study confirmed the substantial utility of MDM2 IHC and MDM2 DISH in the diagnosis of DDLPS, especially when lipogenic components were indistinct compared with IHC for p16 and CDK4. Furthermore, automated DISH was more practical than fluorescent in situ hybridization.