Spot scanning proton therapy for unresectable bulky retroperitoneal dedifferentiated liposarcoma: a case report

The development of effective treatment strategies for unresectable retroperitoneal sarcoma is desirable. Herein, we suggest that definitive proton therapy (PT) could be a promising treatment option, regardless of the large size of the tumor. A 52-year-old man presented with a discomfort of the lower abdomen. Computed tomography revealed a retroperitoneal tumor, measuring over 20 cm in the largest dimensions, which was surrounded by the gastrointestinal (GI) tract. Biopsy revealed dedifferentiated liposarcoma. Neoadjuvant chemotherapy was ineffective, and the tumor was ultimately deemed unresectable. The patient opted to receive PT instead of continuation of chemotherapy. Spot scanning PT (SSPT) at a total dose of 60.8 Gy (relative biological effectiveness) in 16 fractions was employed. SSPT administered a dose to the tumor while successfully sparing the surrounding GI tract. He did not receive any maintenance systemic therapy after PT. The tumor gradually shrunk over more than 7 years, with no evidence of recurrence outside the irradiation field. The initial measurable tumor volume of 2925 cc decreased to 214 cc at the final follow-up, seven and a half years after PT. The patient is alive without any severe complications.

Well-differentiated liposarcomas and dedifferentiated liposarcomas: Systemic treatment options for two sibling neoplasms

Well-differentiated liposarcomas (WDLPS) and dedifferentiated liposarcomas (DDLPS) account for 60 % of all liposarcomas, reflecting the heterogeneity of this type of sarcoma. Genetically, both types of liposarcomas are characterized by the amplification of MDM2 and CDK4 genes, which indicates an important molecular event with diagnostic and therapeutic relevance. In both localized WDLPS and DDLPS of the retroperitoneum and the extremities, between 25 % and 30 % of patients have local or distant recurrence, even when perioperatively treated, with clear margins present. The systemic treatment of WDLPS and DDLPS remains a challenge, with anthracyclines as the gold standard for first-line treatment. Several regimens have been tested with modest results regarding their efficacy. Herein we discuss the systemic treatment options for WDLPS and DDLPS and review their reported clinical efficacy results.

DDIT3-amplified or low-polysomic pleomorphic sarcomas without MDM2 amplification: Clinicopathological review and immunohistochemical profile of nine cases

Several high-grade pleomorphic sarcoma cases that cannot be classified into any existing established categories have been reported. These cases were provisionally classified into undifferentiated pleomorphic sarcoma (UPS). Some dedifferentiated liposarcoma (DDLS) cases may also have been classified into the UPS category due to the absence of MDM2 amplification or an atypical lipomatous tumor/well-differentiated liposarcoma component. We retrieved and reviewed 77 high-grade pleomorphic sarcoma cases, initially diagnosed as UPS in 66 cases and DDLS in 11 cases. Fluorescence in situ hybridization (FISH) analyses of DDIT3 and MDM2 were performed for available cases. Of the cases successfully subjected to DDIT3 FISH (n = 56), nine (7 UPS and 2 DDLS) showed DDIT3 amplification but no MDM2 amplification. Two UPS cases showed both telomeric (5') and centromeric (3') amplification of DDIT3 or low polysomy of chromosome 12, whereas 5 UPS and 2 DDLS cases showed 5'-predominant DDIT3 amplification. Histopathologically, all cases showed UPS-like proliferation of atypical pleomorphic tumor cells. Immunohistochemically, only one case showed focal nuclear positivity for DDIT3, supporting the previous finding that DDIT3 expression was not correlated with DDIT3 amplification. All three cases with focal MDM2 expression involved 5'-predominant amplification, two of which showed DDLS-like histological features. The majority of cases (7/9) showed decreased expression in p53 staining, suggesting that DDIT3 amplification regulates the expression of TP53 like MDM2. From a clinicopathological perspective, we hypothesize that DDIT3-amplified sarcoma, especially with 5'-predominant amplification, can be reclassified out of the UPS category.

Retroperitoneal dedifferentiated liposarcoma with rare heterologous low-grade osteosarcoma: A case report

Dedifferentiated liposarcoma is a high-grade entity developed from a preexisting or recurrent well-differentiated liposarcoma, and rarely, it may contain divergent differentiation. We presented the case of a 39-year-old woman with retroperitoneal dedifferentiated liposarcoma with heterologous low-grade osteosarcoma, possessing a special pattern of tumoral calcification.

Dedifferentiated liposarcoma of the orbit

Purpose

To present a rare case of dedifferentiated liposarcoma of the orbit.

Observations

A 61-year-old male complained of left-sided proptosis, diplopia, and limited ocular motility for two years. Biopsy results at that time were suggestive of an atypical lipomatous neoplasm. Ten years later, he presented with increase in size of the mass and worsening of his symptoms. Imaging showed a multi-lobulated mass in the left orbit involving the intraconal, medial, and anterior orbit. Decompression and orbitotomy with biopsy were performed to debulk the mass. Pathology showed a low-grade well-differentiated liposarcoma and the patient was monitored thereafter annually. Eight years later, he complained of persistent proptosis and mass effect from the tumor resulting in ptosis and diplopia and underwent orbital exenteration. Histopathological analysis of the exenterated orbit revealed a focal area of dedifferentiated liposarcoma.

Conclusions and importance

Dedifferentiation of an orbital mass can occur as a late complication years after the diagnosis of well-differentiated liposarcoma. Compared to the previously published cases of orbital liposarcoma, this presentation shows a prolonged timeline prior to dedifferentiation (18 years after initial diagnosis). Symptoms of growth or invasive features could indicate dedifferentiation and should warrant a biopsy.

Characteristic findings of primary perirenal angiosarcoma on chemical shift subtraction magnetic resonance imaging (CSS-MRI): A case report

A 70-year-old man with supraglottic carcinoma underwent computed tomography (CT) for staging purposes. A tumor measuring approximately 7 × 10 cm was found incidentally in the left perirenal space. The tumor showed homogeneous high signal intensity on chemical shift subtraction magnetic resonance imaging (CSS-MRI) suggesting the presence of minimal amounts of fat. Five months later, the tumor had grown to approximately 10 × 12 cm with indistinct margins. CSS-MRI showed high signal intensity in the tumor periphery only. The tumor was resected and the pathological diagnosis was angiosarcoma. Angiosarcomas are malignant endothelial vascular neoplasms that are highly invasive to their surroundings. Here we report a case of primary perirenal angiosarcoma that was difficult to differentiate from a dedifferentiated liposarcoma. On CSS-MRI, high signal intensity within a tumor may be a characteristic feature of primary perirenal angiosarcoma.

Atypical lipomatous tumor/well differentiated liposarcoma and related mimics with updates. When is molecular testing most cost-effective, necessary, and indicated?

The classification and work-up of adipocytic neoplasms remains challenging and sometimes controversial. Since its initial description by Dr. Enterline, the variety of subtypes and morphological appearances considered to represent the spectrum of atypical lipomatous tumor/well differentiated liposarcoma (ALT/WDL) has expanded, resulting in significant morphologic overlap with other entities, including the recently described atypical spindle cell/pleomorphic lipomatous tumor (ASPLT), conventional spindle cell/pleomorphic lipoma (SPL), and so-called "low-grade" forms of dedifferentiated liposarcoma (DL). Nevertheless, the distinction of most examples of ALT/WDL from lipomas/lipoma-like lesions is easily performed on routine histologic examination but can be problematic if the characteristic atypical cells are poorly represented, particularly in small biopsy specimens, obscured by other cellular elements (inflammation), or simply not recognized. The discovery that lipomatous tumors harbor specific and unique karyotypes and molecular events has resulted in ancillary tests that can help provide more accurate diagnoses, especially in less-than-optimal scenarios. Confirmation of MDM2 immunohistochemical over-expression and detection of the MDM2 gene rearrangement via fluorescent in situ hybridization (FISH) have proven particularly reliable and useful. While FISH analysis for MDM2 gene amplification may be helpful for confirming (or excluding) ALT/WDL, it also can lead to overutilization and overdependence. Furthermore, a small subset of otherwise typical ALT/WDL lack MDM2 gene amplification, employing alternative molecular pathways. The recent recognition of ASPLT has introduced a tumor easily mistaken morphologically for ALT/WDL, often exhibiting bizarre and pleomorphic lipoblasts, but lacking the underlying molecular abnormalities and subsequent risk of dedifferentiation. ASPLT also have overlapping features with the better-established SPL but with a greater tendency to locally recur and more frequent involvement of the distal extremities. The precise criteria separating cellular forms of ALT from what some consider "low grade" forms of DL remains controversial and inconsistently applied, even among individual pathologists within institutions. Given their underlying shared cytogenetic abnormality, molecular testing has no utility in this distinction. Herein is a comprehensive historical overview of ALT/WDL, with updates on its distinction from other similar lipomatous tumors and DL, including practical evidence-based criteria for the appropriate cost-effective use of MDM2 testing.

Massive dedifferentiated thigh liposarcoma growing for 10 years and extending into the retroperitoneum: a case report

Liposarcomas are rare, malignant tumors of adipocyte differentiation. Surgery is the main treatment method. We are reporting a rare case of a 65- year- old female patient with a massive dedifferentiated thigh liposarcoma that was growing for 10 years and spread to the retroperitoneum.

Giant dedifferentiated liposarcoma of the gastrocolic ligament: A case report

BACKGROUND

Dedifferentiated liposarcoma (DDLS) has a worse prognosis and occurs most commonly in the retroperitoneal region and rarely in the intraperitoneal region. Histological diagnosis was revolutionized by the combined contributions of histo-immuno-chemistry and molecular biology. Aside from surgery, there is no consensus on the optimal treatment for this chemoresistant cancer.

CASE SUMMARY

A thirty-year-old black female presented with a large painful abdominal mass occupying nearly the entire abdomen and progressive weight loss was admitted for surgery. Abdominal computed tomography showed a large heterogeneous mass of the mesentery that was sized 18 cm × 16 cm in size and had heterogeneous contrast enhancement. During laparotomy, en bloc excision of the large and multilobulated gastrocolic ligament mass was performed. The initial postoperative histopathological diagnosis was undifferentiated sarcoma. Finally, the results of immunohistochemistry and molecular biology allowed us to confirm the diagnosis of DDLS. The tumour followed an aggressive evolution with diffuse metastasis, causing the death of the patient less than 5 mo after the operation.

CONCLUSION

Dedifferentiated liposarcomas are rare tumours that typically originate in the retroperitoneum but may arise in unexpected locations.

Giant primary liposarcoma of the mediastinum: A case report and review of the literature

Liposarcoma is a carcinomatous mesenchymal tumor with various histologic features and is the most common soft tissue sarcoma originating in adipose tissue. Liposarcoma commonly occurs in the lower extremities and retroperitoneum but rarely in the mediastinum, specially extending into the thoracic cavity. We report a giant primary liposarcoma of the posterior mediastinum in a 63-year-old female who complained of cough, sputum, and pain in the right chest wall. A computed tomography scan of the chest showed a giant mass of 24 × 15 × 24 cm in the posterior mediastinum of the right thoracic cavity. After a thorough examination, no suspected lipomatous lesions were found elsewhere in the patient's body. The patient underwent a thoracotomy to remove the mediastinal mass through a right thoracic approach. Subsequently, hematoxylin-eosin staining revealed dedifferentiated liposarcoma (DDL), immunohistochemistry showed positive expression of cyclin-dependent kinase 4, and murine double minute 2 (MDM2), in addition, fluorescence in situ hybridization for the MDM2 gene was also positive, which suggested DDL. The patient was discharged without any complications, and no metastasis or recurrence was observed after 19 months of follow-up. To provide a reference for clinical diagnosis and treatment, we reviewed and discussed the literature on primary liposarcoma of the mediastinum.

Dedifferentiated liposarcoma lung metastases with different FDG-PET/CT findings

BACKGROUND

Dedifferentiated liposarcoma (DDLPS) is a rare tumor and generally shows poor prognosis with the lung frequent metastatic site. 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) is used for staging or metastatic evaluation of this disease. We report a case of bilateral lung metastases of DDLPS showing uncommon imaging on FDG-PET/CT with completely different FDG uptake, which made preoperative diagnosis difficult.

CASE PRESENTATION

The patient was a male in his 60 s and bilateral lung nodules were noted after proton beam therapy for retroperitoneal DDLPS. FDG-PET/CT showed high FDG uptake in the left S3 15-mm nodule but no uptake in the right S8 10-mm nodule. Thoracoscopic wedge resection for the left nodule was performed, and the pathology revealed metastasis of dedifferentiated liposarcoma. After resection of the left nodule, the right S8 nodule enlarged without FDG uptake. Thoracoscopic right S8 segmentectomy was performed, and metastasis of dedifferentiated liposarcoma was diagnosed. The 2 tumors showed completely different appearances on FDG-PET/CT with similar histopathological findings.

CONCLUSIONS

We encountered a case of multiple pulmonary metastases of DDLPS which did not follow the same imaging appearance on FDG-PET/CT. Appropriate timing of surgical resection for pathological diagnosis should be determined carefully.

Recurrent metastatic retroperitoneal dedifferentiated liposarcoma: a case report and literature review

BACKGROUND

Retroperitoneal liposarcoma (RPLPS), a rare tumor, is often treated using surgical procedures as the first choice for treatment. However, there is no consensus on the scope of surgical resection. In addition, the treatment outcomes of conventional radiotherapy and chemotherapy have not been satisfactory, particularly for specific types of LPS, such as dedifferentiated LPS. In this case study, we present a brief review of other cases of RPLPS, highlighting the selection of surgical scope for RPLPS and related adjuvant treatment for advanced RPLPS.

CASE PRESENTATION

A case study is reported regarding an extremely rare recurrent and metastatic retroperitoneal dedifferentiated LPS. The primary RPLPS tumor, with a diameter of 20 cm and a weight of 2.5 kg, occupied the whole left abdomen and adhered to the left kidney. A surgical tumor resection combined with a left nephrectomy is performed. During the 6th -month postoperative follow-up examination, we observed the local recurrence of the tumor in the operation area, in addition to multiple metastatic tumors in both lungs. Further, the prescribed 3-month targeted treatment with anlotinib significantly reduced the size of the metastatic pulmonary tumors. However, the recurrent retroperitoneal tumors showed no significant change in size. Eventually, we observed no substantial evidence of tumor progression, with the patient's condition under control.

CONCLUSION

The case demonstrated that the postoperative recurrence of widespread RPLPS required R0 resection to cure the disease, considering targeted therapy for advanced RPLPS control.

Three dimensional models of dedifferentiated liposarcoma cell lines: scaffold-based and scaffold-free approaches

Sarcomas are rare malignancies, the number of reports is limited, and this rarity makes further research difficult even though liposarcoma is one of major sarcomas. 2D cell culture remains an important role in establishing basic tumor biology research, but its various shortcomings and limitations are still of concern, and it is now well-accepted that the behavior of 3D-cultured cells is more reflective of in vivo cellular responses compared to 2D models. This study aimed to establish 3D cell culture of liposarcomas using two different methods: scaffold-based (Matrigel extracellular matrix [ECM] scaffold method) and scaffold-free (Ultra-low attachment [ULA] plate). Lipo246, Lipo224 and Lipo863 cell lines were cultured, and distinctive differences in structures were observed in Matrigel 3D model: Lipo224 and Lipo863 formed spheroids, whereas Lipo246 grew radially without forming spheres. In ULA plate approaches, all cell lines formed spheroids, but Lipo224 and Lipo863 spheroids showed bigger size and looser aggregation than Lipo246. Formalin fixed, paraffin embedded (FFPE) blocks were obtained from all 3D models, confirming the spheroid structures. The expression of MDM2, Ki-67 positivity and MDM2 amplification were confirmed by IHC and DNAscope™, respectively. Protein and DNA were extracted from all samples and MDM2 upregulation was confirmed by western blot and qPCR analysis. After treatment with MDM2 inhibitor SAR405838, DDLPS spheroids demonstrated different sensitivity patterns from 2D models. Taken together, we believed that 3D models would have a possibility to provide us a new predictability of efficacy and toxicity, and considered as one important process in in vitro pre-clinical phase prior to moving forward to clinical trials.

A case of dedifferentiated liposarcoma of the descending colon

A 54-year-old man referred to our hospital for abdominal distension. He had no medical history. On physical examination, he complained lower abdominal distention, and had no spontaneous pain or tenderness. The blood tests showed that CEA and CA19-9 levels were within normal limits. Colonoscopy revealed a submucosal tumor with irregularities and mucosal defects in the descending colon. Computed tomography (CT) showed a 3-cm-diameter mass in the descending colon and ascites. Due to the presence of ascites, laparoscopic examination was performed, which revealed multiple peritoneal seeding of the tumor. Given the presence of peritoneal dissemination, the tumor was determined to be unresectable, and a histological examination was performed from the disseminated nodule. Pathologically, atypical spindle cells were observed and infiltrated into adipose tissue. Additional immunohistochemistry revealed positive expression for Murine double minute 2 (MDM2) and Cyclin-dependent kinase 4 (CDK4), and fluorescence in situ hybridization showed amplification of MDM2. Thus, the tumor was diagnosed with a dedifferentiated liposarcoma of the descending colon. Liposarcoma is a type of soft-tissue sarcoma that arises from soft tissues such as the extremities or retroperitoneum. Here, we report an extremely rare case of a dedifferentiated liposarcoma of the colon.

Dedifferentiated liposarcoma in the extremity and trunk wall: A multi-institutional study of 132 cases by the Japanese Musculoskeletal Oncology Group (JMOG)

BACKGROUND

Dedifferentiated liposarcoma occurs predominantly in the retroperitoneum. Given the paucity of cases, information on the clinical characteristics of this entity in the extremities and trunk wall is quite limited. In particular, the significance of preoperative evaluation and principles of intraoperative management of the different components, i.e., well-differentiated and dedifferentiated areas, are still to be defined.

METHODS

Clinical characteristics, treatment outcomes, and risk factors for poor oncological outcomes in cases of dedifferentiated liposarcoma in the extremity or trunk wall were analyzed by a retrospective, multicentric study.

RESULTS

A total of 132 patients were included. The mean duration from the initial presentation to dedifferentiation was 101 months in dedifferentiation-type cases. The 5-year local recurrence-free survival, metastasis-free survival, and disease-specific survival rates were 71.6%, 75.7%, and 84.7%, respectively. Among 32 patients with metastasis, 15 presented with extrapulmonary metastasis. A percentage of dedifferentiated area over 87.5%, marginal/intralesional margin, and R1/2 resection in the dedifferentiated area were independent risk factors for local recurrence. Dedifferentiated areas over 36 cm², French Federation of Cancer Centers Sarcoma Group grade III, and intralesional or marginal resection were independent risk factors for metastasis. A dedifferentiated area over 77 cm² and lung metastasis were independent risk factors for disease-specific mortality.

CONCLUSIONS

The typical clinical characteristics of dedifferentiated liposarcoma in the extremity and trunk wall were reconfirmed in the largest cohort ever. The evaluation of the dedifferentiated area in terms of grade, extension, and pathological margin, together with securing adequate surgical margins, was critical in the management of this entity.

Multiple Recurrent Atypical Lipomatous Tumors/Well-Differentiated Liposarcomas and Dedifferentiated Liposarcomas Treated with Multiple Surgical Resections: A Case Report

Atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDLPS) is usually a solitary adipocytic tumor. ALT/WDLPS shows no potential for metastasis unless it undergoes dedifferentiation. No case of multiple ALT/WDLPS has been reported in recent years. We present a rare case of multiple recurrent liposarcomas. A 71-year-old man with a history of scrotal ALT/WDLPS at 61 years presented with multiple large tumors spread throughout the body. The patient was bedridden and severely limited in his activities of daily living (ADL) due to multiple large tumors in the trunk and lower extremities. Radiological examination revealed multiple adipocytic tumors, mainly in the soft tissues of the trunk and extremities, with several visceral lesions. Tumors were resected in stages, starting with large tumors directly related to disability. Repeated palliative resections improved the patient's ADL; he regained ambulation and was discharged 18 months after admission. Twelve surgeries were performed to remove 44 adipocytic tumors from the testis, left chest wall, perigastric area, ileum, left inguinal region, both buttocks, thighs, and lower legs. Histological examination revealed dedifferentiated components in five tumors, while 39 tumors were diagnosed as ALT/WDLPS. At the age of 76 years, the patient developed an unresectable dedifferentiated liposarcoma between the heart and aorta, leading to fatality at 79 years. The patient's clinical course suggested multiple metastases of ALT/WDLPS of scrotal origin or ALT/WDLPS of multicentric origin. Although multicentric ALT/WDLPS or ALT/WDLPS metastases are rare, they should be considered when multiple large adipocytic tumors are found throughout the body. Despite the presence of numerous large malignant tumors, surgical treatments of the lesions can improve ADL and prolong life if the tumors are of low-grade malignancy.

Giant retroperitoneal dedifferentiated liposarcoma mimicking ovarian cancer: A case report

•

Clinical features of the dedifferentiated subtype of LPS that has a diameter of >30 cm remains unknown.

•

Surgical resection entails a high risk due to the size and anatomical location and difficulty in preoperative diagnosis.

•

CT is the most useful imaging method for evaluating tumor location, size, origin, and relationship to adjacent organs.

•

Retroperitoneal LPS should be considered in the case of a giant intra-abdominal tumor with a fatty component.

•

Surgical resection is the mainstay of treatment for retroperitoneal LPS.

Retroperitoneal liposarcoma is a rare tumor, and its dedifferentiated subtype and a larger diameter are associated with a poor prognosis. However, there are few reports of retroperitoneal liposarcomas, both with a dedifferentiated subtype and a diameter of >30 cm. We report a case of a giant retroperitoneal liposarcoma with a dedifferentiated subtype. A 78-year-old woman presented to our hospital with abdominal distension and loss of appetite. Computed tomography and magnetic resonance imaging findings revealed a 35-cm-diameter solid tumor in the peritoneal cavity. CA125 (64.8 U/mL) and HE4 (229.0 pmol/L) were elevated preoperatively raising suspicion for ovarian malignancy. However, intraoperative findings revealed that the tumor originated in the retroperitoneal cavity. Reductive surgery for the tumor and partial resection of the sigmoid colon and left ureter were performed, and pathological examination confirmed a retroperitoneal dedifferentiated liposarcoma. Although her symptoms improved postoperatively, she died 11 months after surgery due to disease progression.

Atypical spindle cell/pleomorphic lipomatous tumor with a sarcomatous component showing high mitotic activity and Ki-67 labeling index: report of a unique case mimicking dedifferentiated liposarcoma

Atypical spindle cell/pleomorphic lipomatous tumor (ASPLT) is a new entity of benign adipocytic tumor that spans a wide spectrum of histology from adipocytic to spindle cell/pleomorphic tumors. The latter non-adipocytic component rarely shows sarcomatous features although ASPLTs are not thought to dedifferentiate. A 78-year-old woman with ASPLT in the left thigh had a sarcomatous component with high mitotic activity and Ki-67 labeling index (LI) mimicking dedifferentiated liposarcoma. The adipocytic component consisted of various-sized adipocytic cells with few lipoblasts. The sarcomatous component consisted of a fascicular proliferation of atypical spindle cells with scattered large bizarre and multinucleated giant cells. Mitotic figures including atypical mitoses were frequently observed. Immunohistochemically, the tumor cells were positive for cluster of differentiation 34 but not mouse double minute 2 homolog (MDM2), cyclin-dependent kinase 4 (CDK4), or retinoblastoma (Rb) protein. Ki-67 LI in the sarcomatous component reached 40%. MDM2 and CDK4 genes were not amplified and 13q14 including the RB1 locus was deleted according to fluorescence in situ hybridization. The patient is alive with no evidence of local recurrence or distant metastasis 3.5 years after surgery. As ASPLT may exhibit morphological variation, it is important to rule out dedifferentiated liposarcoma with careful pathological examination.

[Histological, immunohistochemical and molecular study of a paratesticular dedifferentiated liposarcoma with inflammatory myofibroblastic tumor-like features]

We report the histological, immunohistochemical, and molecular findings of a dedifferentiated liposarcoma with inflammatory myofibroblastic tumor-like features occurring in the paratesticular region. Histologically, the dedifferentiated component closely resembled an inflammatory myofibroblastic tumor. The neoplastic cells were positive for smooth muscle actin with focal CD56, CD99, Bcl2 and EMA expression. WT1, calretinin, myogenin, CK(AE1/AE3), desmin, H-caldesmon, CD34, ALK, CKIT, DOG1, MUC4 and STAT6 were negative. MDM2 showed diffuse and strong nuclear positivity in neoplastic cells and fluorescence in situ hybridization (FISH) revealed amplified MDM2 (high level) but no SYT rearrangement. Although a lipomatous component was evident macroscopically, well-differentiated liposarcomatous components were not evident in the section examined. Dedifferentiated liposarcoma can have prominent inflammatory myofibroblastic tumor-like features. Pathologists should be aware of this histological variant in order to avoid misdiagnosing dedifferentiated liposarcoma as inflammatory myofibroblastic tumor or other spindle cell tumors which have different behavioral patterns and treatment requirements.

Retroperitoneal and Mesenteric Liposarcomas

Retroperitoneal liposarcomas are a rare entity and are comprised mostly of the well-differentiated and dedifferentiated subtypes. Eight-year survival ranges from 30% to 80% depending on histologic subtype and grade. Surgery is the cornerstone of treatment and compartment resection is the current standard. Mesenteric liposarcomas are extremely rare and comprise more high-grade lesions, with poorer prognosis of 50% 5-year overall survival. They are managed with a similar aggressive surgical approach. This review presents the current management of retroperitoneal and mesenteric liposarcomas.

Primary gastric dedifferentiated liposarcoma resected endoscopically: A case report

BACKGROUND

Liposarcoma is one of the most common adult mesenchymal tumors but is uncommon in the gastrointestinal tract and extremely rare in the stomach. Furthermore, the histological subtypes of liposarcoma usually reported in the stomach are well-differentiated or myxoid, and few reports have been issued on small-sized gastric liposarcomas resected endoscopically and followed up. Herein, we report a case of primary gastric dedifferentiated liposarcoma (DL) that was resected endoscopically.

CASE SUMMARY

A 67-year-old female Korean patient was referred to our institution for further evaluation of a gastric submucosal tumor (SMT) located in the lesser curvature of the gastric body by esophagogastroduodenoscopy. Endoscopic ultrasound revealed a well-circumscribed, slightly heterogeneous, isoechoic, 17 mm × 10 mm sized mass originating from the third sonographic layer. Computed tomography showed no evidence of significant lymph node enlargement or distant metastasis. Endoscopic resection was undertaken using the snare resection technique after mucosal precutting to provide a definitive histopathologic diagnosis, which proved to be consistent with DL, based on its morphology and the immunoexpressions of MDM2 and CDK4. The patient was planned for surgery because the deep resection margin was positive for malignancy. After declining any invasive procedure or adjuvant treatment, the patient was placed under close follow-up, and at one year after endoscopic resection, remained disease free.

CONCLUSION

This is the first reported case of a small primary gastric DL resected endoscopically and followed up. This report demonstrates that when diagnosis of a SMT is uncertain, the use of invasive techniques, including endoscopic resection, should be considered.

Dedifferentiated liposarcoma (DDLPS) in the rectum: A case report

Dedifferentiated liposarcoma (DDLPS) is a rare subtype of liposarcoma with a poor prognosis. This current case report describes a rectal DDLPS in a 68-year-old Chinese male that presented with lower abdominal pain and weight loss. Computed tomography and magnetic resonance imaging were undertaken to evaluate the tumour. The patient underwent radical resection of the rectal tumour, sigmoid colostomy and partial ureterectomy. The tumour was positive for mouse double minute 2 by immunohistochemistry. The patient healed well but refused chemotherapy postoperatively for economic reasons. The tumour recurred and metastasized 4 weeks after the operation. After relevant treatment, the patient's condition deteriorated and he died of shock, metabolic acidosis, hyperlactataemia and acute renal failure. The case report also reviews the literature in terms of the clinical diagnosis, treatment and pathological characteristics of rectal DDLPS with the aim of improving the level of diagnosis and treatment.

Establishment and characterization of a novel patient-derived cell line of dedifferentiated liposarcoma, NCC-DDLPS6-C1

Dedifferentiated liposarcoma (DDLPS) is morphologically characterized by well-differentiated liposarcomas associated with high-grade non-lipogenic sarcoma and molecularly characterized by the coamplification of MDM2 and CDK4(12q14-15). DDLPS is highly aggressive, and effective systemic chemotherapy has not been developed yet. In this study, we established a novel DDLPS cell line, NCC-DDLPS6-C1, as a potential tool for the development of novel therapies. NCC-DDLPS6-C1 cells were established from surgically resected tumor tissues of a patient with DDLPS. Amplification and overexpression of MDM2 and CDK4 were observed in NCC-DDLPS6-C1 cells. NCC-DDLPS6-C1 cells proliferated rapidly, invaded aggressively, and formed spheroids. Moreover, NCC-DDLPS6-C1 cells formed tumors in mice. These observations suggested that the malignant potentials that may reflect the original features of DDLPS were retained in the NCC-DDLPS6-C1. Anticancer drugs that significantly reduced the proliferation of NCC-DDLPS6-C1 cells were identified by drug library screening. Thus, NCC-DDLPS6-C1 may recapitulate the original genotypes and phenotypes, and we conclude that the NCC-DDLPS6-C1 cell line is a useful resource for the study of DDLPS.

Establishment and characterization of NCC-DDLPS5-C1: a novel patient-derived cell line of dedifferentiated liposarcoma

Dedifferentiated liposarcoma (DDLPS) is a highly aggressive subtype of liposarcoma that is morphologically defined as a transition from a well-differentiated lipomatous component to a non-lipogenic one. Curative therapy for DDLPS is complete resection, and the benefits of current systemic chemotherapy remain marginal. Although DDLPS is molecularly characterized by co-amplification of MDM2 and CDK4 (12q14-15) and detailed genomic analyses have been conducted by multiple research groups, the effects of molecular targeted drugs are marginal, and novel therapeutic modalities are required. Although patient-derived cell lines are pivotal for cancer research, no DDLPS cell lines are currently available from public cell repositories. Accordingly, in this study, we established a novel DDLPS cell line, NCC-DDLPS5-C1, using surgically resected tumor tissues from a patient with DDLPS. NCC-DDLPS5-C1 cells exhibited typical gene amplification, overexpression of MDM2 and CDK4, and other DNA copy number alterations. The NCC-DDLPS5-C1 cells were capable of rapid cell proliferation, aggressive invasion, and spheroid formation, but not tumor formation in mice. We reported the utility of NCC-DDLPS5-C1 cells for a drug-response assay to detect anticancer drugs that significantly attenuated cell proliferation. Thus, we concluded that the NCC-DDLPS5-C1 cell line could be a useful resource for the study of DDLPS. Considering the diversity of disease in terms of clinical outcomes, continuous efforts are required to develop more patient-derived cancer models with different clinical and pathological backgrounds.

Dedifferentiated Liposarcoma: A Rare Case Report of Retroperitoneal Myxoid Soft Tissue Tumour with Diagnostic Dilemma

Background:

The retroperitoneum can host a wide spectrum of soft tissue lesions. These tumours pose a challenge to the pathologist as the morphology is not of much help and immunohistochemistry becomes a necessity.

Case report:

Sixty years old male presented with 2 months history of abdominal lump, pain and dyspepsia. The MRI revealed a heterogeneous mass in the retroperitoneum involving right para spinal muscle, right iliac fossa and right perinephric region with destruction of right transverse process and erosion of adjacent L3 vertebra. Trucut biopsy of the mass was reported as fibroliposarcoma at an outside lab. Patient underwent a wide local excision. Grossly the tumour gave an impression of a liposarcoma but the microscopy showed areas of spindle cells, epitheloid cells, focal areas of ganglion like cells and large areas of myxoid change. IHC panel of S-100, SMA, caldesmon, myogenin, myoglobin and Alk-1 was negative. MDM2, CDK4 and p16 IHC came positive proving it to be a dedifferentiated liposarcoma.

Conclusion:

We report a curious case of retroperitoneal soft tissue tumour with complex morphology and IHC features diagnosed as dedifferentiated liposarcoma based on MDM2, CDK and p16 positivity.

Detection of MDM2 gene amplification on tissue microarray-based Fluorescence In-Situ Hybridization (FISH) in well-differentiated and dedifferentiated liposarcomas, displaying a wide morphological spectrum: A validation study at a tertiary cancer referral centre

BACKGROUND

Liposarcomas including atypical lipomatous tumors (ALT)/well-differentiated liposarcomas (WDLPS) and dedifferentiated liposarcomas (DDLPSs) display a histomorphological spectrum with their several diagnostic mimics. Murine double minute 2(MDM2) gene amplification characterizes ALT/WDLPS and DDLPS. Presently, there is no documented study from our subcontinent on the validation of MDM2 gene testing in these tumors.

MATERIAL AND METHODS

Twenty-eight cases, diagnosed as ALT/WDLPS (n = 5) and DDLPSs (n = 23), along with 10 other tumors were tested for MDM2 gene amplification, using fluorescence in situ hybridization (FISH) on tissue microarrays (TMAs). Fourteen cases, diagnosed as ALT/WDLPS and DDLPS, along with 49 other tumors were tested for MDM2 immunostaining. Twenty tumors were tested for p16^INK4a immunostaining.

RESULTS

FISH was interpretable in 25 (89.2%) cases. Among the 20 cases diagnosed as DDLPSs, 19 displayed MDM2 gene amplification. Among the 5 cases diagnosed as ALT/WDLPS, four showed MDM2 gene amplification. Finally, 19 cases were confirmed as DDLPS and 4 as ALT/WDLPS. Furthermore, 7/19 cases confirmed as DDLPS and all 4 cases as ALT/WDLPS tested for MDM2 immunostaining, displayed its diffuse immunoexpression, while a single case of DDLPS showed its focal immunostaining. None of the 49 control cases displayed diffuse MDM2 immunoexpression. ALL 16 DDLPSs and 4 cases of ALT/WDLPS displayed p16^INK4a immunostaining. The sensitivity for diffuse MDM2 immunostaining was 87.5% in cases of DDLPS, 100% in ALT/WDLPS, and specificity was 100%. The sensitivity for MDM2 gene amplification was 94.7% in cases of DDLPS and 100% in cases of ALT/WDLPS. The sensitivity for p16^INK4a was 100%.

CONCLUSION

This constitutes the first sizable study on MDM2 testing in ALT/WDLPS and DDLPS from our subcontinent using TMAs. MDM2 gene amplification testing continues as the diagnostic gold standard for ALTs/WDLPSs and DDLPSs and is useful in cases of diagnostic dilemmas. Diffuse MDM2 (IF2 clone) and p16^INK4a immunostaining, together seem useful for triaging cases for FISH.

A successful trimodality therapy for difficult-to-diagnose primary mediastinal dedifferentiated liposarcoma, which originated from the perihilar fat and invaded the right lungs

A 40-year-old man with high fever, hemoptysis, and fatigue showed a 10-cm mass in the middle and lower lobes of the right lung on computed tomography. Histological examination of transbronchial biopsy specimens showed sheets of small round tumor cells and mild staining for CD99. Primary Ewing sarcoma was suspected, and a trimodality therapy consisting of chemotherapy, intensity-modulated radiation therapy, and right pneumonectomy with surrounding tissue resection was performed. In surgical specimens, negative outcome of NKX2.2 in immunostaining and EWSR1 rearrangement in fluorescence in situ hybridization did not support the diagnosis of Ewing sarcoma. Positive immunostaining for MDM2 and CDK4 led to a diagnosis of dedifferentiated liposarcoma, which probably originated from an adipose tissue of the right perihilar mediastinum, and then invaded the lungs. The postoperative course was uneventful, without recurrence for more than 16 months.

Expression of FRS2 in atypical lipomatous tumor/well-differentiated liposarcoma and dedifferentiated liposarcoma: an immunohistochemical analysis of 182 cases with genetic data

Background

The fibroblast growth factor receptor substrate 2 (FRS2) gene is located close to MDM2 and CDK4 within the 12q13-15 chromosomal region. FRS2 gene was recently found to be consistently amplified in atypical lipomatous tumor (ALT)/well-differentiated liposarcoma (WDL) and dedifferentiated liposarcoma (DDL), suggesting the detection of FRS2 amplification could be a diagnostic tool for ALT/WDL/DDLs. However, the expression of FRS2 protein and diagnostic value of FRS2 immunohistochemistry (IHC) has not been evaluated in a large cohort of ALT/WDL/DDLs.

Methods

A SNOMED search of hospital surgical pathology files from January 2007 to July 2020 identified 182 ALT/WDL/DDLs with available materials. FRS2 fluorescence in situ hybridization (FISH) and IHC were performed on 182 ALT/WDL/DDLs and 64 control samples. The expression of FRS2 was also compared with that of classic immunomarkers (MDM2 and CDK4) of this tumor entity.

Results

This study included 91 ALT/WDLs and 91 DDLs. The FISH results showed 172 of 182 (94.5%) cases were FRS2-amplified, and 10 cases were FRS2-nonamplified. Immunostaining results showed 171 (94.0%) ALT/WDL/DDLs were positive for FRS2 and 11 cases (6.0%) were FRS2-immunonegative. In 172 FRS2-amplified cases, 166 (96.5%) were FRS2-immunopositive, and 6 (3.5%) were negative. Among 10 FRS2-nonamplified ALT/WDL/DDL cases, 5 cases were FRS2-immunonegative, and 5 tumors displayed 1+ staining for this marker. In 64 control cases, none of them exhibited FRS2 amplification. Forty-seven (73.5%) control cases were negative for FRS2 immunostaining, while 17 cases (26.5%) were FRS2-immunopositive. Fifteen of these false positive samples (15/17, 88.2%) showed 1+ positivity and only 2 cases (2/17, 11.8%) displayed 2+ positivity. In ALT/WDL/DDLs, the sensitivity of FRS2 immunostaining was slightly lower than MDM2 (FRS2 vs. MDM2: 94.0% vs 100.0%) and CDK4 (FRS2 vs. CDK4: 94.0% vs 97.0%). However, the specificity of FRS2 (73.5%) was slightly higher than that of MDM2 (67.8%) and CDK4 (64.4%).

Conclusion

This study indicated that FRS2 IHC had relatively good consistency with FRS2 FISH, suggesting that FRS2 immunostaining could be utilized as an additional screening tool for the diagnosis of ALT/WDL/DDL. It must be emphasized that MDM2/CDK4/FRS2 especially MDM2 FISH remains the gold standard and the most recommended method to diagnose this entity.

Retroperitoneal Dedifferentiated Liposarcoma

OBJECTIVES

We aimed to test the hypothesis that in retroperitoneal dedifferentiated liposarcoma (DDLS) the presence of the dedifferentiated (DD) component at the resection margin is associated with adverse outcome.

METHODS

We retrospectively searched the archive for primary resections of retroperitoneal DDLS performed at our institution between 1990 and 2017. Slides were rereviewed for diagnosis, Fédération Nationale des Centres de Lutte Contre le Cancer grade, myogenic differentiation, and the presence of the well-differentiated (WD) or DD component at the resection margin. The medical records were reviewed for patient age, sex, tumor size, tumor focality, adjuvant/neoadjuvant therapy, local recurrence, distant metastases, local recurrence-free survival (LRFS), overall survival (OS), and follow-up duration.

RESULTS

The presence of the DD component at the resection margin was associated with worse LRFS compared with cases without the DD component at the margin (P = .002). However, OS was not significantly affected (P = .11).

CONCLUSIONS

LRFS is significantly shorter in cases with the DD component at the margin compared with cases without DD tumor at the margin, while there is no association with OS. We recommend reporting the presence or absence of DD tumor at the margin in retroperitoneal DDLS, as it adds meaningful prognostic information.

The utility of fluorescence in situ hybridization (FISH) in determining DNA damage-inducible transcript 3 (DDIT3) amplification in dedifferentiated liposarcomas - an important diagnostic pitfall

BACKGROUND AND OBJECTIVE

Dedifferentiated liposarcoma (DDLPS) is characterized by non-lipogenic sarcoma fields coexisting with adipocyte-rich well-differentiated areas. Amplification of the 12q13-15 region includes the MDM2 and DDIT3 genes. MDM2 amplification is considered a genetic hallmark of DDLPS, while DDIT3 is typically rearranged in myxoid liposarcoma. Recent studies showed that DDIT3 amplification is associated with myxoid liposarcoma-like (LPS-like) morphology in DDLPS. Our study aimed to evaluate the status of MDM2 and DDIT3 by FISH in DDLPS and correlate it with MLPS-like features.

MATERIAL AND METHODS

Six patients with MLPS-like morphology DDLPS were investigated pathologically, immunohistochemically, and genetically. The control groups of patients with classical DDLPS morphology and well-differentiated liposarcoma (WDLPS) were established and molecularly assessed as well. Fluorescence in situ hybridization (FISH) used in routine diagnostics was performed to determine the status of MDM2 and DDIT3 genes.

RESULTS

The patient's mean age was 64 (range from 43 to 85 years) with a 5:4 male to female ratio. Tumors were localized retroperitoneally (15) and extra-retroperitoneally (3). All cases demonstrated amplification of the 12q15 region containing MDM2 gene and co-amplification of the 5' DDIT3 FISH Probe representing DDIT3 telomeric tag. However, we did not find the relation of myxoid LPS-like morphology with DDIT3 amplification as previously reported.

CONCLUSIONS

The biopsy material from DDLPS with myxoid areas can be misclassified as myxoid liposarcoma. Indeed, according to the histological image, DDIT3 status may be evaluated first. In these cases, we show that the DDIT3 telomeric tag amplification assessed by FISH, is a common, nonspecific feature, which is also found in classical DDLPS and WDLPS. Therefore, we believe that co-amplification of DDIT3 and MDM2 may be considered a spectrum of the 12q13-15 region amplification due to the specification of FISH methodology.

Dedifferentiated liposarcoma with heterologous spindle cell rhabdomyoblastic de-differentiation: An unusual pattern expanding the morphological spectrum

Dedifferentiated liposarcoma (DDLS) is characterized by a wide histopathological spectrum. Spindle cell type of rhabdomyoblastic dedifferentiation has been rarely described in case of DDLS. A 39-year-old male presented with a recurrent retroperitoneal tumor mass, diagnosed as well-differentiated liposarcoma, for which he underwent surgical excisions on two occasions, followed by adjuvant radiation therapy previously. Computed tomogram scan his of abdomen revealed a large-sized, fat-containing recurrent, retroperitoneal mass, measuring 18.1 cm in the largest dimension. Histopathologic examination of the resected tumor revealed distinct areas of well- and dedifferentiated liposarcoma, including areas reminiscent of a myxofibrosarcoma, further progressing into a high-grade spindle cell sarcoma with fascicular and "Herringbone-like" growth patterns (fibrosarcoma-like). Immunohistochemically, high-grade spindle cell sarcomatous (dedifferentiated) component displayed distinct positivity for desmin and MyoD1, along with focal tumor nuclei, showing nuclear positivity for myogenin. Both well-differentiated liposarcomatous and dedifferentiated components displayed diffuse, intense nuclear positivity for MDM2 (overexpression) and p16INK4A. Furthermore, upon testing tumor sections displaying spindly sarcomatous areas for MDM2 amplification, by FISH technique, nearly all tumor cells displayed MDM2 gene amplification. This case constitutes one of the rare cases of DDLS displaying spindle cell rhabdomyoblastic dedifferentiation. Its diagnostic and treatment implications are discussed herewith.

Obvious Reduction of the Tumor Size in Dedifferentiated Liposarcoma in a Lung Metastasis Patient Receiving Individualized Treatment

Abdominal metastasis is relatively rare in dedifferentiated liposarcoma of the shoulder and back. Surgery is the best treatment option, whether it is radical or palliative surgery. Chemotherapy is the standard systemic treatment for advanced unresectable/metastatic patients, but the therapeutic effect is limited. Here, we treat advanced abdominal dedifferentiated liposarcoma through a comprehensive treatment method of targeting, surgery, and chemotherapy, which improves the quality of life of the patient, and shrinks the tumor significantly.

Inhibition of P53-mediated cell cycle control as the determinant in dedifferentiated liposarcomas development

Liposarcomas are a heterogeneous group of sarcomas, including well-differentiated and dedifferentiated liposarcoma, myxoid/round cell liposarcoma, and pleomorphic liposarcoma. Complete surgical resection is the key of treatment. Radiotherapy, based on the tumor grade and the vicinity of critical structures with the tumor, can be used to prevent local recurrence. The group of dedifferentiated liposarcomas (DDLS) is poorly sensitive to adjuvant chemotherapy. Improved understanding of the genetic aberrations that lead to liposarcoma initiation is necessary for the development of targeted therapies to improve tumor control and survival. DDLS share genetic abnormalities with other groups, exhibiting high-level amplifications of chromosome 12, including the MDM2 and CDK4 genes, and harbor additional amplifications of chromosomes 6 and 1. Novel therapies targeted at the gene products of chromosome 12 are currently considered in clinical trials. Our work consisted in a genomic characterization of DDLS to draw up a complete picture of alterations, including genomic signatures, tumor mutation burden, gene mutations, copy number variations, translocations, gene fusions and methylation modifications. Analysis of translocations helped to understand the mechanisms underlying the amplification processes. Combination of mutations and loss of heterozygosity or homozygous deletions were detected and led to inactivate tumor suppressor genes (TSG). In contrast, methylation anomalies seemed not linked to any particular genomic profile. All identified anomalies, whether amplifications and/or TSG inactivation, involve genes playing a role in p53 regulation, that appears to be the epicenter of the initiation process in DDLS tumorigenesis, as is also known to be responsible for Li-Fraumeni syndrome, a family cancer syndrome highly predisposing to sarcomas.

Establishment and characterization of NCC-DDLPS3-C1: a novel patient-derived cell line of dedifferentiated liposarcoma

Dedifferentiated liposarcoma (DDLPS) is a highly malignant subtype of liposarcoma, with characteristic amplification of MDM2 and CDK4 (12q14-15). It is caused by the dedifferentiation of well-differentiated liposarcoma. DDLPS is refractory to conventional chemotherapy; thus, surgical resection is the primary treatment modality. However, complete resection of DDLPS is difficult because of its deep location, which results in poor prognosis. Therefore, novel systemic chemotherapy is required to improve the clinical outcome. Patient-derived cell lines are important tools in the development of novel chemotherapy. However, there are no DDLPS cell lines available from public cell banks. In this study, we established a novel DDLPS cell line, NCC-DDLPS3-C1, using a surgically resected specimen from a patient with DDLPS. NCC-DDLPS3-C1 cells retained the characteristic gene amplification of MDM2 and CDK4. In addition, other gene amplifications and losses related to the poor prognosis of DDLPS were also observed in concordance with the original tumor. The cells also exhibited rapid cell proliferation, aggressive invasion ability, spheroid formation ability, and tumorigenic ability in nude mice. Furthermore, a drug-screening test showed significant antiproliferative effects of proteasome inhibitors and HDAC inhibitors. Thus, the NCC-DDLPS3-C1 cell line should be a useful tool for the development of novel chemotherapy for DDLPS.

Update on genomic and molecular landscapes of well-differentiated liposarcoma and dedifferentiated liposarcoma

Well-differentiated liposarcoma (WDLPS) is the most frequent subtype of liposarcoma and may transform into dedifferentiated liposarcoma (DDLPS) which is a more aggressive subtype. Retroperitoneal lesions of WDLPS/DDLPS tend to recur repeatedly due to incomplete resections, and adjuvant chemotherapy and radiotherapy have little effect on patient survival. Consequently, identifying therapeutic targets and developing targeted drugs is critical for improving the outcome of WDLPS/DDLPS patients. In this review, we summarised the mutational landscape of WDLPS/DDLPS from recent studies focusing on potential oncogenic drivers and the development of molecular targeted drugs for DDLPS. Due to the limited number of studies on the molecular networks driving WDLPS to DDLPS development, we looked at other dedifferentiation-related tumours to identify potential parallel mechanisms that could be involved in the dedifferentiation process generating DDLPS.

Selinexor versus doxorubicin in dedifferentiated liposarcoma PDXs: evidence of greater activity and apoptotic response dependent on p53 nuclear accumulation and survivin down-regulation

BACKGROUND

Dedifferentiated liposarcoma (DDLPS), a tumor that lacks effective treatment strategies and is associated with poor outcomes, expresses amplified MDM2 in the presence of wild-type p53. MDM2 ubiquitination of p53 facilitates its XPO1-mediated nuclear export, thus limiting p53 tumor suppressor functions. Consequently, nuclear export is a rational target in DDLPS. We directly compared the antitumor activity of the first-in class XPO1 inhibitor selinexor and doxorubicin, the standard front-line therapy in sarcomas, in DDLPS patient-derived xenografts (PDXs) and primary cell lines.

METHODS

Drug activity was assessed in three PDXs (and two corresponding cell lines) established from the dedifferentiated component of primary untreated retroperitoneal DDLPS with myogenic (N = 2) and rhabdomyoblastic (N = 1) differentiation from patients who underwent surgery. These models were marked by amplification of MDM2, CDK4 and HMGA2 genes.

RESULTS

Selinexor was moderately active in the three PDXs but achieved greater tumor response compared to doxorubicin (maximum tumor volume inhibition: 46-80 % vs. 37-60 %). The PDX harboring rhabdomyoblastic dedifferentiation showed the highest sensitivity to both agents. PDX response to selinexor and doxorubicin was not associated with the extent of MDM2 and CDK4 gene amplification. Interestingly, the most chemosensitive PDX model showed the lowest extent of HMGA2 amplification. Selinexor was also more efficient than doxorubicinin in inducing an apoptotic response in PDXs and cell lines. Consistently, an increased nuclear accumulation of p53 was seen in all selinexor-treated models. In addition, a time-dependent decrease of survivin expression, with an almost complete abrogation of the cytoplasmic anti-apoptotic pool of this protein, was observed as a consequence of the decreased acetylation/activation of STAT3 and the increased ubiquitination of nuclear survivin.

CONCLUSIONS

Selinexor showed a moderate antitumor activity in three DDLPS PDXs, which was, however, consistently higher than doxorubicin across all different models regardless the extent of MDM2 amplification and the histological differentiation. The depletion of survivin protein seems to significantly contribute to the induction of apoptosis through which selinexor exerts its antitumor activity.

An oncologic emergency case of massive dedifferentiated liposarcoma of the small bowel mesentery

We report the case of a 71-year-old man who complained of abdominal distension, pedal edema, respiratory discomfort, and weight gain. Computed tomography revealed a giant, poorly enhancing tumor occupying the entire abdomen, with abdominal ascites. The tumor was causing hydronephrosis, compression of the inferior vena cava, and elevation of the diaphragm. The patient exhibited deterioration of performance status (PS3 on the ECOG scale) and required oxygen; therefore, emergency surgery was performed. Operative findings included bloody abdominal ascites and peritoneal dissemination. The large tumor arose from the small bowel mesentery, and infiltrated into the cecum and sigmoid colon. Tumor excision with ileocecal resection and sigmoidectomy was performed. Histopathological examination revealed dedifferentiated liposarcoma. The patient was discharged on postoperative day 22, but pre-discharge CT revealed a recurrent liposarcoma in the retroperitoneum. Therefore, chemotherapy was initiated and the treatment has been continued for over 6 months after surgery. Due to the rarity of this disease, there is no consensus regarding treatment strategies for DDLPS with peritoneal dissemination or in patients with a poor general condition, especially in the setting of oncologic emergency. In this case, multimodal treatment was used to successfully manage this life-threatening state and obtain satisfactory therapeutic results.

Establishment and characterization of a novel cell line, NCC-DDLPS2-C1, derived from a patient with dedifferentiated liposarcoma

Dedifferentiated liposarcoma (DDLPS) is a highly aggressive subtype of liposarcoma that is histologically a transition form between an atypical lipomatous tumor/well-differentiated liposarcoma and a non-lipogenic sarcoma. DDLPS is genetically characterized by a complex karyotype with copy number variations and genomic complexity. DDLPS has a poor prognosis, a high local recurrence rate, and refractory behaviors for chemotherapy and radiation, which indicate a requirement for a novel therapeutic strategy for better clinical outcomes. We report here, a novel DDLPS cell line (NCC-DDLPS2-C1) developed from a tumor tissue. NCC-DDLPS2-C1 cells showed an amplified 12q13-15 region and exhibited constant growth, spheroid formation, and invasion. High-throughput drug screening revealed distinct sensitivity between monolayer- and three-dimensional cells. Romidepsin and trabectedin especially showed high anti-proliferative effects in both culture methods of NCC-DDLPS2-C1. Thus, the NCC-DDLPS2-C1 cell line may serve as a useful resource for DDLPS studies.

Primary dedifferentiated Liposarcoma of vagina: a first case report

BACKGROUND

Dedifferentiated liposarcoma, one of the most deadly types of soft tissue sarcoma, is an aggressive and high-grade form of liposarcoma. Liposarcoma occurs most commonly in the retroperitoneum, extremities and trunk, but less frequently in the female genital tract. The vagina is a very rare site of origin. Herein we report the first case of dedifferentiated Liposarcoma deriving from vagina and discuss its clinical course.

CASE PRESENTATION

A 38-year-old female patient presented to our institution with a painless vaginal mass. Abdominal computed tomography showed a 17.6 cm× 10.4 cm solid mass originating from the right lateral wall of her vagina. Then she underwent complete surgical resection of the tumor mass, and postoperative pathological result confirmed the diagnosis of dedifferentiated liposarcoma deriving from vagina. Six courses of combination chemotherapy with pirarubicin plus ifosfamide were performed after surgery. The patient remains with no evidence of disease recurrence with 13 months of follow-up.

CONCLUSIONS

Liposarcoma is very rare in female genital tract, and more rare for dedifferentiated liposarcoma in gynecologic field. Little is known about the clinical characteristics, pathological diagnosis, prognosis and optimal management strategy of vaginal dedifferentiated liposarcoma. Complete surgical resection followed by systemic chemotherapy is suggested to be standard treatment for dedifferentiated liposarcoma. Combination chemotherapy with pirarubicin and ifosfamide may be effective for treating vaginal dedifferentiated liposarcoma.

Clinical features of multiply recurrent retroperitoneal liposarcoma: A single-center experience

BACKGROUND

To elucidate the clinicopathological features of multiply recurrent retroperitoneal liposarcoma referred to a tertiary center.

METHODS

We retrospectively analyzed the clinical data of 40 patients with pathologically proven primary retroperitoneal liposarcoma treated between January 2015 and June 2019.

RESULTS

The initial pathology was well-differentiated liposarcoma (WDLS) in 23 patients, dedifferentiated liposarcoma (DDLS) in 15 patients, and myxoid liposarcoma in two patients. Before and after referral to our hospital, the patients underwent 142 surgeries (median number of surgeries: 3) for initial and recurrent tumors. Of these, 35 (87.5%) patients underwent surgeries for recurrent tumors. In 11 (47.8%) of the 23 patients with initial WDLS, pathological progression (PP) to DDLS was observed in recurrent tumors at the median interval of 7.8 years. In eight patients (72.7%), the PP occurred at the first recurrence. In contrast, all 15 patients with DDLS recurred as DDLS. Distant metastases developed in eight patients (34.8%) with WDLS and five patients (29.4%) with DDLS/myxoid subtype. All eight WDLS patients who developed metastasis were alive with disease at the median interval of 3.6 years, whereas four of the five patients with primary diagnosis of DDLS/myxoid subtype died at the median interval of 5.6 months from the development of metastasis. The 5-year overall survival of the patients with initial WDLS and those with DDLS/myxoid subtype were 100% and 67.4% (p = 0.0006), respectively.

CONCLUSIONS

The prognosis of the initial-WDLS patients was favorable despite multiple recurrences. In WDLS patients, if distant metastases develop, it is possible to remain alive with disease for years.

Giant recurrent liposarcoma of the retroperitoneum - A surgical challenge: A case report

•

Giant retroperitoneal dedifferentiated liposarcoma can extend to the scrotum.

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Dedifferentiated histologic subtypes of liposarcomas are associated with poor prognosis.

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Performing an en bloc resection through a right iliac incision extended to the scrotum.

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Obtaining negative margins after surgical resection is the curative treatment.

•

Careful follow-up to detect early recurrence is essential for optimal care.

Introduction

Sarcomas are a rare entity with heterogeneous clinical behavior. We herein present the case of a giant retroperitoneal dedifferentiated liposarcoma and aim to remind the clinical, histological, and therapeutic features of this rare tumor.

Presentation of case

An 80-year-old patient was complaining of significant abdominoscrotal swelling. On physical examination, a 25-cm swelling extending from the right iliac fossa to scrotums, was observed. CT scan revealed a retroperitoneal fatty mass with necrotic areas. Ultrasonography-guided biopsy was carried. Pathological report demonstrated a dedifferentiated sarcoma. An en bloc resection of the tumor was performed through a right iliac incision extended to the scrotum. After one year of follow up, the patient had a 30-cm local recurrence. After complete resection, the patient died two days after the procedure due to neurological distress.

Discussion

‘Giant’ liposarcomas over 20kg are extremely rare. CT-Scan and MRI are very useful for defining their size and limits. The resection of a retroperitoneal sarcoma of remarkable size is a challenge for the surgeon owing to the anatomical site that makes it hard to obtain safe margin and to the adherences with the contiguous organs. Dedifferentiated histologic subtypes and negative surgical margins are associated with poor prognosis. This explains the high rate of local recurrence after surgical excision.

Conclusion

In rare cases, retroperitoneal dedifferentiated liposarcomas can extend through the inguinal canal to the scrotum. Surgical resection obtaining negative margins, remains the curative treatment that reduces the risk of recurrence. Careful follow-up to detect early recurrence is essential for optimal care.

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.

Dedifferentiated Liposarcoma of the Descending Colon: A Case Report and Review of the Literature

Dedifferentiated liposarcomas are rare; localization of these tumors in the descending colon is extremely uncommon. We describe the case of a 75-year-old man with a dedifferentiated liposarcoma originating from the descending colon that manifested as partial bowel obstruction. The very uncommon presentation of this rare disease contributed to a challenging diagnostic process. The patient was successfully treated by surgical resection of the mass through left hemicolectomy. Although exceptionally unusual, soft tissue sarcomas should be considered in the differential diagnosis for bowel obstruction. Currently, radical resection of the mass is considered to be the first-line treatment.

Recombinant Methioninase Combined With Tumor-targeting Salmonella typhimurium A1-R Induced Regression in a PDOX Mouse Model of Doxorubicin-resistant Dedifferentiated Liposarcoma

BACKGROUND/AIM

Dedifferentiated liposarcoma (DDLPS) is associated with a poor survival rate even with multi-modality treatment. In the present study, we evaluated the efficacy of recombinant methioninase (rMETase) combined with tumor-targeting Salmonella typhimurium (S. typhimurium) A1-R against a doxorubicin-resistant DDLPS in a patient-derived orthotopic xenograft (PDOX) mouse model.

MATERIALS AND METHODS

A recurrent high-grade DDLPS from the right retroperitoneum of a patient was grown orthotopically in the retroperitoneum of nude mice to establish a PDOX model. The PDOX models were randomly divided into the following groups: Control, no treatment; doxorubicin monotherapy; rMETase monotherapy; S. typhimurium A1-R monotherapy; S. typhimurium A1-R and rMETase combination therapy. Tumor length and width were measured before and after treatment.

RESULTS

On day 14 after treatment, all treatments significantly inhibited DDLPS PDOX tumor growth compared to the untreated control except for doxorubicin monotherapy. rMETase combined with S. typhimurium A1-R was significantly more effective and regressed tumor volume compared to either rMETase or S. typhimurium A1-R alone. The relative body weight did not significantly differ between days 0 and 14 for individual groups.

CONCLUSION

The combination of rMETase and S. typhimurium A1-R has important clinical potential for this recalcitrant sarcoma.

Thoracoscopic resection of a huge esophageal dedifferentiated liposarcoma: A case report

BACKGROUND

Esophageal liposarcoma is a rare malignant tumor and an esophageal dedifferentiated liposarcoma (DDL) is extremely rare. There are no reports on the treatment of DDL by thoracoscopic surgery.

CASE SUMMARY

A 38-year-old woman presented with dysphagia and dyspnea. Imaging examination showed a large mass in the posterior mediastinum. The patient also developed respiratory failure and it was unclear whether this was caused by a mass from inside or outside the esophagus. We decided to perform thoracoscopic exploration to relieve the obstruction caused by tracheal compression. The upper segment of the esophagus was split longitudinally, and most of the mass could be removed from the esophageal lumen to the thoracic cavity. The pedicle was excised by linear cutting closers under mirrors. Little residual mass was visualized by gastroscopy. The mucous and muscular layers were closed by interrupted sutures. Pathological examination showed that the mass was a DDL. The patient did not have any dysphagia or dyspnea 2 wk postoperatively and refused any further treatment. Computed tomography and esophagoscopy did not find any recurrence at up to 20 mo postoperatively.

CONCLUSION

Thoracoscopy can be used to treat large esophageal masses.

Combining surgery with 125I brachytherapy for recurrent mediastinal dedifferentiated liposarcoma: A case report and review of literature

BACKGROUND

Dedifferentiated liposarcoma in the mediastinum is an extremely rare malignant neoplasm. A few previous case reports indicate that surgical resection is the major treatment, but frequent recurrence occurs locally. Due to its rarity, its clinical characteristics, optimal treatment and clinical outcomes remain unclear. Here, we report a case of multifocal recurrent dedifferentiated liposarcoma in the posterior mediastinum treated by combining surgery with ¹²⁵I brachytherapy, and summarize its clinical features, treatment and prognosis.

CASE SUMMARY

A 75-year-old man was admitted to our hospital with a history of gradual dysphagia for one year and aggravated dysphagia for 3 mo. Contrast-enhanced computed tomography (CT) revealed several large cystic-solid masses with lipomatous density, and calcification in the posterior-inferior mediastinum. The patient received a wide excision by video-assisted thoracoscopic surgery. Pathological analysis confirmed the tumors were dedifferentiated liposarcomas. The tumor locally relapsed 24 mo later, and another operation was performed by video-assisted thoracoscopic surgery. Fifteen months after the second surgery, the tumor recurred again, and the patient received CT-guided radioactive seeds ¹²⁵I implantation. After 8 mo, follow-up chest CT showed an enlarged tumor. Finally, his condition exacerbated with severe dysphagia and dyspnea, and he died of respiratory failure in July 2018.

CONCLUSION

We reviewed the literature, and suggest that surgical resection provides beneficial effects for dedifferentiated liposarcoma in the mediastinum, even in cases with local recurrence. ¹²⁵I brachytherapy may be beneficial for recurrent unresectable patients.

Accurate 3-gene-signature for early diagnosis of liposarcoma progression

Background

Well- and dedifferentiated liposarcoma (WD/DDLPS) are rare mesenchymal malignant tumors that account for 20% of all sarcomas in adults. The WD form is a low-grade malignancy with a favourable prognosis which may progress to DDLPS, a high-grade aggressive counterpart. WDLPS is referred to as atypical lipomatous tumour (ALT) when localised in extremities, due to its better prognosis. Currently the final differential diagnosis to distinguish between more aggressive and less aggressive form is based on post-surgical histological examination and no molecular biomarkers for early detection are available.

Methods

Quantitative polymerase chain reaction (qPCR) analysis of 11 metabolic genes involved in general and adipose tissue-specific metabolism, was performed on ALT (= 8), WDLPS (= 9) and DDLPS (= 20) samples. Subsequent statistical analysis was carried out to determine genes that most accurately can predict DDLPS differential diagnosis. Selected genes were further validated in a separate cohort by qPCR and the data statistically analysed. Deep sequencing was performed on DDLPS specimen from the metastatic patient and on five random WDLPS specimens.

Results

We established a three-gene signature based on PNPLA2, LIPE and PLIN1, which identified DDLPS with 100% sensitivity and 90% specificity, even in specimens from the WD component of DDLPS tumors. Interestingly, the PNPLA2 gene is deleted in 45% of DDLPS samples analyzed under TCGA project, and the deletion is associated with significantly lower PNPLA2 expression level. However, other mechanisms causing loss or downregulation of the expression of these three genes may be involved. Moreover, the significantly lower level of PNPLA2 is associated with R1 surgical margins, compare to R0 margins, which suggests the more invasive tumor phenotype in the absence of PNPLA2.

Conclusions

The identified metabolic signature allows highly accurate differential diagnosis between WD- and DDLPS even in samples containing lipid droplets, a marker of differentiation, which makes it very suitable for the use on biopsies. In respect to the pathogenesis of the disease, our results give a new insight into possible molecular mechanisms involved and support the recent observation that deletion of PNPLA2 is a novel factor in liposarcoma progression.

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.

Dedifferentiated Liposarcoma: Systemic Therapy Options

OPINION STATEMENT

Over the last several years, the systemic treatment landscape for dedifferentiated liposarcoma (DDLPS) has notably expanded. Historically, systemic therapy options have been limited to cytotoxic chemotherapy agents, including doxorubicin, ifosfamide, gemcitabine, and docetaxel, that were shown to have efficacy in unselected populations of patients with soft tissue sarcomas. More recently, however, there have been phase II and III trials establishing clinical benefit of the cytotoxic agents trabectedin and eribulin along with the tyrosine kinase inhibitor pazopanib in patients with advanced liposarcoma and DDLPS. Additionally, there are several investigational targeted therapies that have incorporated advances in the understanding of DDLPS disease biology, exploiting the fact that nearly all such tumors include highly amplified expression of MDM2 and CDK4. Recent clinical trials have supported the benefit of the CDK4 inhibitor abemaciclib and the nuclear export inhibitor selinexor and support continued development of anti-MDM2 therapies, with particular attention to the bone marrow toxicity and resultant thrombocytopenia that has thus far limited their use. In contrast, the checkpoint inhibitors pembrolizumab and nivolumab remain of questionable benefit, although these immunotherapy drugs may have a role when combined with other therapeutic agents. Ongoing phase III trials will clarify the role of these novel agents. Future directions include directly comparing current standard-of-care options and newer therapies, developing synergistic combinations of novel agents, and evaluating their role in patients with localized DDLPS.