Liposarcomas of the posterior mediastinum: clinicopathologic study of 18 cases

Pleomorphic Liposarcoma Cytologically Detected in Hemosiderotic Pleural Effusion: Pitfalls Mitigated by Cytologic Clues and Cellblock Immunocytochemistry

Sarcomatous serous effusions are uncommon and diagnostically challenging. Dedifferentiated and pleomorphic liposarcomas are rare tumors in pleural effusions revealing highly pleomorphic tumor cells mimicking carcinoma, mesothelioma, melanoma, and other sarcomas. Hematothoracic effusions further complicate the cytologic diagnosis. Correct cytologic recognition is important. We report pleomorphic liposarcoma cytologically detected in effusion fluid in a 56-year-old man who presented with a massive unilateral pleural effusion. ThinPrep showed hemorrhagic effusion fluid characterized by lysed red blood cells, foamy macrophages, and siderophages intermixed with highly pleomorphic predominantly naked mononuclear and giant nuclei. The aggregated siderophages and vacuolated macrophages could be mistaken for tumor cells, whereas the bare nuclei may be missed as nonspecific degenerate changes. Cellblock sections showed highly pleomorphic mononuclear and multinucleated giant tumor cells with diagnostic lipoblasts, intermixed with foamy macrophages and siderophages. Cellblock immunocytochemistry showed staining for vimentin and S-100 protein in the tumor cells. Other lineage-specific immunomarkers were negative. CD68 and calretinin revealed frequent background macrophages and scarce mesothelial cells. The tumor cells were negative for MDM2 and CDK4. The entertained cytopathologic diagnosis was pleomorphic liposarcoma. Core needle biopsy was procured from the mass. The histopathologic features and immunoprofile of the tissue specimen matched the cytopathologic and immunocytochemical findings confirming the cytologic diagnosis of pleomorphic liposarcoma. Pleomorphic liposarcoma is an unexpected cytologically challenging finding in effusions, particularly when compounded by pitfalls introduced by hemosiderotic fluid. Attention to certain cytologic clues mitigate pitfalls. Cellblock is a valuable diagnostic tool when integrated with relevant negative and positive immunocytochemical markers.

Mediastinal liposarcoma: Case report with radiology review

De-differentiated primary mediastinal liposarcomas account for less than 1% of all liposarcoma pathology. We report the case of an 82-year-old male who was suffering from progressive dysphagia, shortness of breath, and dysphonia for a period of 2 months. A CT scan of the chest with contrast revealed a large heterogeneously enhancing posterior mediastinal mass extending into the posterior soft tissues of the neck, abutting bilateral carotid arteries, and displacing the trachea and esophagus. Treatment chosen for our patient was surgical resection followed by adjuvant radiation therapy which resolved the patient's presenting symptoms. The insights gained through the diagnosis, management, and treatment of our patient can be utilized to approach this type of rare neoplasm.

Dedifferentiated Mediastinal Liposarcoma: A Case Report

Liposarcoma is the most common soft tissue sarcoma type in adults, originating mainly from the retroperitoneum and lower extremities. Mediastinal liposarcomas constitute an extremely rare clinical entity of mesenchymal origin. Among subtypes, dedifferentiated liposarcoma is characterized by poor survival, but little is known about its biological behavior. We present the case of a 78-year-old male patient who presented with vague symptoms, predominantly dyspnea and chest pain. Imaging revealed a large mediastinal mass and surgical resection was performed in a piecemeal manner due to the inability to achieve a microscopically negative surgical margin (R0 resection) for the residual tumor. Histological examination confirmed the diagnosis of dedifferentiated liposarcoma. The patient's postoperative course was uneventful, with discharge from the hospital on the 10th postoperative day. However, local recurrence was detected after two months and the patient died four months after the operation. The present case report highlights the importance of radical excision for the prevention of local recurrence and the presentation of histological characteristics of this tumor. Radical surgical resection remains the fundamental treatment, while chemo and radiotherapy may have an adjuvant role. In cases of inability to obtain negative margins, surgical debulking can offer symptomatic relief.

MDM2 for the practicing pathologist: a primer

The mouse double minute 2 (MDM2) gene is located on the long arm of chromosome 12 and is the primary negative regulator of p53. The MDM2 gene encodes an E3 ubiquitin-protein ligase that mediates the ubiquitination of p53, leading to its degradation. MDM2 enhances tumour formation by inactivating the p53 tumour suppressor protein. The MDM2 gene also has many p53-independent functions. Alterations of MDM2 may occur through various mechanisms and contribute to the pathogenesis of many human tumours and some non-neoplastic diseases. Detection of MDM2 amplification is used in the clinical practice setting to help diagnose multiple tumour types, including lipomatous neoplasms, low-grade osteosarcomas and intimal sarcoma, among others. It is generally a marker of adverse prognosis, and MDM2-targeted therapies are currently in clinical trials. This article provides a concise overview of the MDM2 gene and discusses practical diagnostic applications pertaining to human tumour biology.

Primary Dedifferentiated Liposarcoma of the Posterior Mediastinum With a Positive Surgical Margin

Liposarcoma often occurs in the extremities and retroperitoneum. Primary mediastinal liposarcoma is uncommon, and there is no settled opinion regarding adjuvant therapy after surgery. We have recently experienced a relatively rare case of primary dedifferentiated liposarcoma of the posterior mediastinum. The patient was a 76-year-old woman. An abnormal shadow was noted in the posterior mediastinum. Esophageal submucosal tumor and gastrointestinal stromal tumor were suspected; endoscopic ultrasound-guided fine needle aspiration was performed, but a definitive diagnosis could not be obtained. As the tumor tended to slowly grow, surgical resection was performed. Based on histopathological findings, the patient was diagnosed with primary dedifferentiated liposarcoma of the posterior mediastinum. Owing to the presence of a positive surgical margin, postoperative radiotherapy (60 Gy/24 fr/6 w) was administered. No recurrence was observed after three and a half years of follow-up. The prognosis of primary dedifferentiated liposarcoma of the posterior mediastinum with a positive surgical margin is poor, but postoperative radiotherapy may be useful.

Clinicopathological Features of Intrathoracic Liposarcoma-A Systematic Review with an Illustrative Case

BACKGROUND

Liposarcoma (LPS) is one of the most common soft-tissue sarcomas. However, intrathoracic LPS is rare, as only 1% of all LPS cases are found in the thorax.

METHODS

A systematic literature review through PubMed and Embase databases was performed. Only eligible case reports and case series reporting intrathoracic LPS in adult patients were included. Kaplan-Meier curves were calculated to evaluate the survival rate of included patients based on the histological subtype of LPS.

RESULTS

123 studies reporting 197 patients were included. We added a case of a 69-year-old female patient with recurrent giant intrathoracic LPS. The primary tumor measured 15.1cm × 22.9 cm × 21.9 cm and weighed 3100 g. Six months later, the patient was admitted to the hospital with another intrathoracic tumor measuring 9.5 cm × 9 cm× 1.4 cm. The immunohistochemical studies showed expression of murine double minute 2 (MDM2) antigen in both primary and recurrent tumor cells.

CONCLUSIONS

Dyspnea, chest pain, and cough were the most common symptoms reported in included studies. Overall, the 5-year survival rate was 62%. The highest survival was observed in well-differentiated LPS patients (80%) and the lowest in myxoid LPS (31%).

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.

Primary intrathoracic liposarcomas: A clinicopathologic and molecular study of 43 cases in one of the largest medical centers of China

Introduction

Primary intrathoracic liposarcoma is extremely rare, and most published series lack genetic analyses. The aim of our study is to better understand the clinicopathologic and genetic features of these rare lesions.

Materials and methods

Forty-three primary intrathoracic liposarcomas were identified and most cases were analyzed by systematic genetic studies, including fluorescence in situ hybridization (FISH), whole-exome sequencing (WES), and Sanger sequencing.

Results

This series included 27 males and 16 females (ratios, 1.68:1) aged 24-73 years (median, 53 years). Tumors mainly occurred in the mediastinum (n=23, 53.5%), followed by pleural cavity (n=16, 37.2%) and lung (n=4, 9.3%). The study included 21 well-differentiated liposarcomas (WDLs), 19 dedifferentiated liposarcomas (DDLs), 2 myxoid pleomorphic liposarcomas (MPLs) and 1 pleomorphic liposarcoma (PL), without identification of myxoid liposarcoma. FISH analysis identified MDM2 amplification in 17 of 18 WDLs (94.4%) and all DDLs (16/16, 100.0%). The MDM2-nonamplified WDL was CDK4-nonamplified but FRS2-amplified. WES and Sanger sequencing found somatic TP53 mutation in the 2 MPLs. Follow-up information was available for 33 of 38 cases (86.8%). Thirteen patients (39.4%) showed no evidence of disease, 10 patients (30.3%) were alive with disease, and 8 patients (24.2%) died of disease. Fourteen cases developed recurrence and 1 with metastasis.

Conclusions

WDL/DDL was the overwhelming subtype in this location, followed by MPL and PL. Analysis of the FRS2 gene, in combination with MDM2 and other genes of 12q13-15, may more precisely characterize WDL/DDLs. MPL is the most fatal subtype of this site. Further studies are needed to explore the role of TP53 in the pathogenesis of MPL.

Mesenchymal Tumors of the Mediastinum: An Update on Diagnostic Approach

Mesenchymal tumors of the mediastinum are a heterogenous group of rare tumors with divergent lineages. Mediastinal mesenchymal tumors are diagnostically challenging due to their diversity and morphologic overlap with nonmesenchymal lesions arising in the mediastinum. Accurate histologic diagnosis is critical for appropriate patient management and prognostication. Many mediastinal mesenchymal tumors affect distinct age groups or occur at specific mediastinal compartments. Neurogenic tumors, liposarcoma, solitary fibrous tumor, and synovial sarcoma are common mesenchymal tumors in the mediastinum. Herein, we provide an update on the diagnostic approach to mediastinal mesenchymal tumors and a review of the histologic features and differential diagnosis of common benign and malignant mesenchymal tumors of the mediastinum.

Sarcomas of the mediastinum with epithelioid morphology

While soft tissue sarcomas typically have a spindled or pleomorphic appearance, a subset of malignant soft tissue neoplasms can have a prominent epithelioid morphology. In complex anatomic sites such as the mediastinum, such tumors can often be mistaken for a carcinoma or mesothelioma. Frequent expression of cytokeratin staining can further confound the diagnostic process and familiarity with these entities can help prevent an erroneous diagnosis. Particular entities that have been reported to occur in the mediastinum with such features include dedifferentiated liposarcoma, pleomorphic liposarcoma, malignant peripheral nerve sheath tumor, synovial sarcoma, SMARCA4-deficient thoracic sarcoma, alveolar soft part sarcoma and clear cell sarcoma. Many of these tumors exhibit unique clinical, genetic, molecular or immunohistochemical features which allow for accurate characterization. For example, pleomorphic liposarcoma contains bizarre appearing lipoblasts and dedifferentiated liposarcoma exhibits MDM2 gene amplification that is typically confirmed by fluorescence in-situ hybridization. Malignant peripheral nerve sheath tumor will often arise in association with a nerve or neurofibroma. Synovial sarcoma consistently exhibits rearrangements involving the SS18 gene and SMARCA4-deficient thoracic sarcoma shows loss of SMARCA4 staining in the tumor cells. Alveolar soft part sarcoma demonstrates an ASPL-TFE3 fusion transcript. Clear cell sarcoma often shows an EWSR1-ATF1 fusion transcript. When encountering a sarcoma of the mediastinum with epithelioid features, familiarity with these and other characteristics can help insure a correct diagnosis.

Liposarcomas of the mediastinum

Liposarcoma is a malignant tumor of adipocytic differentiation that rarely arises within the mediastinum. Most of the existing data available comes from scattered case reports and a few small series. The World Health Organization (WHO) recognizes four basic types of liposarcoma: well-differentiated/atypical lipomatous tumor (ALT), dedifferentiated, myxoid and pleomorphic liposarcoma (PLS). All of these liposarcoma subtypes have been recorded to occur within the mediastinum. On morphologic grounds liposarcoma can present a challenge for diagnosis as it can be difficult to distinguish from benign adipocytic neoplasms, or in the case of dedifferentiated liposarcoma (DDLS), from virtually any other type of sarcoma. Molecularly the most common subtypes of liposarcoma are characterized by specific, recurrent genetic alterations involving amplification events of MDM2 and CDK4 in well-differentiated liposarcoma (WDL) and a recurrent t(12;16)(q13;p11) in myxoid liposarcoma (MLS). MDM2 and CDK4 amplification can be assessed by immunohistochemistry, fluorescence in situ hybridization, or molecular techniques that evaluate copy number alterations and amplifications such as array based assays and next generation sequencing (NGS). In addition to WDL and MLS, a few additional rare subtypes of liposarcoma may occur in the mediastinum including PLS, myxoid WDL, thymoliposarcoma, and sclerosing high-grade liposarcoma. The present review will focus on the clinicopathologic features of the various histologic types of liposarcoma described in the mediastinum and their differential diagnosis. Data is derived from review of the largest series published in the more recent literature on these tumors.

Safe diagnostic management of malignant mediastinal tumors in the presence of respiratory distress: a 10-year experience

BACKGROUND

The fundamental treatment for patients with pediatric malignant mediastinal tumors is chemotherapy. Therefore, accurate diagnosis is essential for selecting the appropriate chemotherapeutic regimen. However, malignant mediastinal tumors occasionally cause respiratory distress, and biopsies under general anesthesia are dangerous for such patients as invasive mechanical ventilation can aggravate airway obstruction caused by mass effect. In this study, we reviewed our 10-year diagnostic experience to evaluate the efficacy of our practices and confirm a safe diagnostic protocol for future patients.

METHODS

We retrospectively reviewed medical records of children with malignant mediastinal tumors diagnosed at Nagoya University Hospital from 2007 to 2018 who demonstrated respiratory distress. Respiratory distress included dyspnea, massive pleural effusion, wheezing, and hypoxemia owing to tumors. Data on sex, age at onset, primary symptoms, location of tumor, management strategy (especially the method of diagnosis and definitive diagnosis), clinical course, prognosis during the acute phase (within 3 months from the onset of respiratory symptoms), and long-term outcome were collected.

RESULTS

Twelve pediatric patients met the review criteria. There were seven anterior mediastinal tumors and five posterior mediastinal tumors. All anterior mediastinal tumors were diagnosed via bone marrow smear, thoracentesis, or core needle biopsy while maintaining spontaneous breathing. Regarding posterior tumors, two patients were diagnosed via a core needle biopsy and lymph node excisional biopsy under spontaneous breathing. Two cases were initially diagnosed solely using tumor markers. One patient with severe tracheal compression underwent tumor resection with extracorporeal membrane oxygenation stand-by. No patient died of diagnostic procedure-related complications.

CONCLUSIONS

In 11 of the 12 cases reviewed, safe and accurate tumor diagnosis was accomplished without general anesthesia. A diagnostic strategy without general anesthesia considering the tumor location proved to be useful.

Neurogenic Tumors of the Mediastinum

Neurogenic tumors represent a broad ill-defined category of neoplasms that includes tumors of Schwann cell and/or neuroblastic derivation, as well as neoplasms that typically develop in the central nervous system, but rarely present in ectopic sites including the mediastinum. Neurogenic tumors may occur at many different anatomic sites, but the mediastinum represents a uniquely challenging site given the complex anatomy. Additionally, some of these neoplasms may present with multicentric involvement in the context of genetic syndromes, including NF1, NF2 and schwanomatosis. Most of these develop in posterior structures, often in association with paraspinal structures. Fine needle biopsy/small biopsies play an important role in the diagnosis of these neoplasms, given its record of safety and the increased applicability of ancillary testing to these smaller samples at the present time. In this review we focus on the major categories of neurogenic tumors that may be encountered in the mediastinum, including schwannoma, neurofibroma, malignant peripheral nerve sheath tumors, ganglioneuroma and ganglioneuroblastoma, as well as rarer members of this category. We discuss diagnostic approaches applicable to small cytologic and tissue samples and relevant differential diagnoses.

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.

Lipomatous Tumors in Pediatric Patients: A Retrospective Analysis of 50 cases

OBJECTIVE

Although lipomatous tumors are the most common type of mesenchymal tumors in adults, they account for less than 10% of all soft tissue lesions in pediatric patients. In this descriptive study, we aim to present our series of pediatric lipomatous tumors consisting of lipoma, neural fibrolipoma, lipoblastoma, atypical lipomatous tumor, myxoid liposarcoma and pleomorphic liposarcoma, and to evaluate the clinicopathological characteristics of these tumors in reference to the literature.

MATERIAL AND METHOD

In this study, pediatric lipomatous tumor cases diagnosed between 2002 and 2018 were screened from pathological archives and retrospectively evaluated.

RESULTS

A total of 50 cases were diagnosed with lipomatous tumor within the mentioned period. Of the total cases, 24 were female (48%) and 26 were male (52%), with age distribution ranging from 1 to 204 months. Histopathological examination revealed lipoma in 26 cases (52%), lipoblastoma in 19 (38%), atypical lipomatous tumor in 2 (4%), myxoid liposarcoma in 2 (4%), and pleomorphic liposarcoma in 1 case (2%).

CONCLUSION

Although lipomatous tumors are the most common type of mesenchymal tumors; they rarely occur in children. Since there is a limited number of studies on pediatric lipomatous tumors in the literature, there is insufficient data on the prevalence and incidence of these tumors. These tumors may slowly enlarge to greater sizes, especially those localized in deep tissues, and may cause various clinical symptoms by compressing surrounding tissues. Local recurrences may occur, even after total excision, and require close monitoring.

Huge primary dedifferentiated pancreatic liposarcoma mimicking carcinosarcoma in a young female: A case report

BACKGROUND

Pancreatic liposarcoma is a rare tumor. According to a literature review, the patient described in this study is the seventh case of pancreatic liposarcoma reported in the English literature and the third case of dedifferentiated liposarcoma. Furthermore, this case had the largest primary tumor volume, and a primary pancreatic liposarcoma was diagnosed based on sufficient evidence.

CASE SUMMARY

We here report a rare case of a 28-year-old female with a huge dedifferentiated liposarcoma in the pancreatic tail. In June 2015, the patient underwent distal pancreatectomy with splenectomy. During the operation, a huge liposarcoma of approximately 28.0 cm × 19.0 cm × 8.0 cm was found, which had a yellow and white fish-like incisal surface. Based on both pathology and MDM2 gene amplification, the tumor was diagnosed as a dedifferentiated liposarcoma. The patient was treated with surgery but declined postoperative chemotherapy. She was well at the 26-mo follow-up, and no relapse was observed.

CONCLUSION

Pancreatic liposarcoma has a low incidence. Chemotherapy should be included in the treatment regimens. Complete resection is the only effective treatment.

Retroperitoneal Well-Differentiated Liposarcoma With Uterine-Type Leiomyomatous Differentiation: A First Case Report With Literature Analysis of Soft Tissue Sarcomas With Dual Lipomatous and Low-Grade Smooth Muscle Differentiation

The occurrence of smooth muscle differentiation in a liposarcoma is a very uncommon phenomenon, even in dedifferentiated liposarcomas. In dedifferentiated liposarcomas, the leiomyosarcomatous component frequently displays high-grade cytologic features, increased mitotic activity, and tumor necrosis. Even more unusual are rare reported cases of low-grade smooth muscle differentiation in atypical lipomatous tumors/well-differentiated liposarcomas (WDLS). The current case describes a 39-year-old female with a large retroperitoneal WDLS harboring a well-demarcated mass composed of benign-appearing smooth muscle fascicles completely lacking cytologic atypia and mitotic activity. In conjunction with the immunopositivity for estrogen and progesterone receptors, the morphology of this nodule was highly reminiscent of a uterine-type leiomyoma. Of note, the lipomatous component largely displayed a lipoma-like appearance with only rare foci of mildly atypical spindle cell proliferation among the adipocytes and few fibrous septae harboring atypical stromal cells. Immunohistochemical and fluorescence in situ hybridization studies revealed MDM2 gene amplification in both the lipomatous and leiomyoma-like areas, thus confirming the diagnosis of a WDLS with smooth muscle differentiation. A literature review on the subject of sarcomas with dual adipocytic and low-grade smooth muscle differentiation provided sufficient supporting evidence to categorize the tumor as a WDLS with “leiomyomatous” differentiation. Pathologists should be aware of the occurrence of uterine-type leiomyomatous differentiation in retroperitoneal WDLS to avoid potential diagnostic errors.

A contemporary review of myxoid adipocytic tumors

Myxoid adipocytic tumors encompass a broad heterogeneous group of benign and malignant adipocytic tumors, which are typically myxoid (e.g. myxoid liposarcoma, lipoblastoma and lipoblastoma-like tumor of the vulva) or may occasionally appear predominantly myxoid (e.g. pleomorphic liposarcoma, atypical lipomatous tumor, dedifferentiated liposarcoma, chondroid lipoma, spindle cell/pleomorphic lipoma, atypical spindle cell lipomatous tumor and atypical pleomorphic lipomatous tumor). There have been significant advances in recent years in classification and understanding the pathogenesis of adipocytic tumors, based on the correlation of histologic, immunohistochemical, and cytogenetic/molecular findings. Despite these advances, the morphologic diagnosis and accurate classification of a myxoid adipocytic tumor can be challenging due to major morphologic overlap between myxoid adipocytic and non-adipocytic tumors. This article will provide a review on the currently known morphological, immunohistochemical and molecular features of myxoid adipocytic tumors and their differential diagnosis.

Primary mediastinal dedifferentiated liposarcoma: Five case reports and a review

Background

Liposarcoma has been subclassified histologically into well‐differentiated, myxoid, pleomorphic, and dedifferentiated types. The dedifferentiated type generally shows poorer prognosis than the well‐differentiated type. Because of its rarity, the clinicopathological features and clinical outcomes of primary mediastinal dedifferentiated liposarcoma remain unclear.

Methods

Five patients with primary mediastinal dedifferentiated liposarcoma were treated at Shinshu University Hospital between January 2012 and August 2017. We investigated the clinical characteristics, including age, gender, radiographic findings, pathological status, and clinical and treatment outcomes.

Results

Four of the five patients initially underwent radical surgical resection. One patient was disease‐free after surgery, but the remaining three patients developed local recurrence in the mediastinum after surgical resection. Two of these patients underwent repeat surgical resection, resulting in long survival (60 and 40 months, respectively), while the other underwent proton beam therapy and showed no evidence of recurrence as of 17 months after treatment. The remaining patient was treated with chemotherapy using doxorubicin because of advanced inoperable disease, but failed to show a response and died within a month of the initiation of chemotherapy. Although the maximum standardized uptake values on fluorodeoxyglucose‐computed tomography were relatively low, there was a slight positive relation between these values and the Ki‐67‐positive ratio in the tumor.

Conclusion

Aggressive treatment by surgical resection should be considered for mediastinal dedifferentiated liposarcoma, even in cases with local recurrence.

Multiple well-differentiated cardiac liposarcoma with a concomitant myocardial lipoma: A case report

A cardiac lipoma and a cardiac liposarcoma are very uncommon conditions; however, the simultaneous development of the two is extremely rare. In addition, the symptoms of these conditions are not evident in the vast majority of cases, making them easily missed during diagnosis. The present case report describes a case of well-differentiated cardiac liposarcoma with a concomitant myocardial lipoma that was misdiagnosed as multiple cardiac lipomas. The ultrasound, computed tomography, and magnetic resonance imaging presentations of the tumour were described. In addition, relevant literature regarding these two types of tumours was reviewed and compared in order to help improve the identification of these types of tumours. This, in turn, may be beneficial in the selection of more appropriate examination and treatment strategies.

Treatment Approaches and Outcomes for Primary Mediastinal Sarcoma: Analysis of 976 Patients

BACKGROUND

Primary mediastinal sarcomas are rare and deadly. Our objective was to describe the clinicopathological features, treatment strategies, and overall survival outcomes for a contemporary cohort of patients diagnosed with primary mediastinal sarcoma in the United States.

METHODS

We queried the National Cancer Database for cases of mediastinal sarcoma diagnosed from 2004 to 2012. Five-year overall survival (OS) was examined using the Kaplan-Meier method. Differences in OS were assessed using log-rank analysis and Cox proportional hazards regression.

RESULTS

The mean age of diagnosis was 53 years (range, 0 to 90) with a male predominance (59.2%). The most common histological subtype was hemangiosarcoma (27.1%). Fewer than half of patients underwent surgery (48.9%), and 19.7% of patients had no treatment. For all patients, OS was 14.8%. The best unadjusted OS was seen in patients treated with surgery and radiation (40.1%); untreated patients had the worst unadjusted OS (4.2%). Of those who underwent surgery (n = 477, 48.9%), OS was significantly better for those who achieved an R0 resection (30.1% versus 18.9%; p = 0.002). In multivariable analysis, surgery combined with radiation therapy was again associated with the best survival (HR, 0.24; 95% CI, 0.16 to 0.36). Other factors associated with improved OS included younger age, fewer comorbidities, and leiomyosarcoma histology. Worse OS was associated with poorly differentiated or undifferentiated grade, metastases, treatment in the New England region, and having Medicaid or no insurance. Sex and tumor size had no effect on OS.

CONCLUSIONS

The 5-year OS for primary mediastinal sarcoma is poor. Surgical resection can be successful and should be considered whenever possible.

Liposarcoma of the Thyroid: A Case Report with a Review of the Literature

BACKGROUND

Liposarcomas of the thyroid gland are extremely rare tumors, and, to our knowledge, only 12 cases have been reported in the English literature. An accurate diagnosis is challenging due to the nonspecific clinical presentation of this cancer, frequently defined just by a swelling of the neck.

PATIENT FINDINGS

We present an 82-year-old woman with liposarcoma of the thyroid, complaining of a fast-growing neck mass. MRI and neck ultrasound showed a large lipomatous mass, which corresponded to a cold nodule in the thyroid scan. After performing a total thyroidectomy, the diagnosis of a well-differentiated liposarcoma of the thyroid gland was made, showing an MDM2 amplification in fluorescence in situ hybridization. Since neither a metastasis nor a residual tumor was found, no further adjuvant therapy was needed.

RESULTS

We searched the literature for previous case reports and identified only 12 cases worldwide to form our database. A demographic as well as clinical and histopathological analysis was made. In most cases, the liposarcoma occurred in patients >60 years of age. All histological subtypes, such as well-differentiated and myxoid liposarcomas, and pleomorphic and dedifferentiated liposarcomas, were found in the literature. In only 38.46% of the cases, an infiltration of the adjacent organs was observed. Surgery was the most common treatment chosen.

CONCLUSIONS

Our review provides clinical and histopathological features of a primary liposarcoma of the thyroid to enable the identifi-cation of this rare tumor entity and assist in the decision-making process regarding therapeutic options and tumor follow-up.

An analysis of clinical characteristics and patient outcomes in primary mediastinal sarcomas

BACKGROUND

Published data concerning primary mediastinal sarcomas are limited to small-sized retrospective series.  This study reviewed the clinical outcomes of these cases from the SEER (surveillance, epidemiology and end results) database.

METHODS

Primary mediastinal sarcomas (1988 - 2013) were assembled from the SEER database. The incidence and 10-year cancer-specific survival rates were compared to other primary mediastinal malignancies (thymic carcinoma, germ cell tumors, neurogenic tumors, Hodgkin / non Hodgkin lymphomas) as well as to non mediastinal sarcomas.

RESULTS

A total of 204 patients were recruited into this cohort. Multivariate analysis showed better overall survival for patients with younger age at diagnosis, low grade [hazard ratio 0.427 (95% CI: 0.224-0.814; P= 0.010)], posterior mediastinum location [hazard ratio 0.458 (95% CI: 0.268-0.781; P= 0.004)], node negative disease [hazard ratio 0.463 (95% CI: 0.232-0.923; P= 0.029)] and surgical treatment [hazard ratio 0.488 (95% CI: 0.336-0.709; P <0.0001)]. Compared to other mediastinal malignancies, primary mediastinal sarcomas have the worst 10-year overall survival. Similarly compared to non mediastinal sarcomas, primary mediastinal sarcomas have worse 10-year overall survival (23% versus 55%).

CONCLUSION

Primary mediastinal sarcoma is a rare entity with worse prognosis compared to non-mediastinal counterparts. Surgical resection plays a particularly important role in the management.

Resection of giant mediastinal liposarcoma via '⊣ shape' incision

Primary mediastinal liposarcomas are extremely rare conditions often resected through standard median sternotomy or lateral thoracotomy. However, the management of a very huge mediastinal tumor involving hemithorax through these two common surgical approaches is always challenging. Herein, we report a case of applying median sternotomy with a sternum transection plus a right fourth intercostal thoracotomy (‘⊣ shape’ incision) to resect a giant primary anterior mediastinal liposarcoma extending into the whole right thorax. The final pathological diagnosis was a well-differentiated liposarcoma. The patient experienced an uneventful recovery. The ‘⊣ shape’ incision is a good backup for the extension of standard median sternotomy and provides a better exposure for both mediastinum and hemithorax.

Myxoid liposarcoma of the foot: a study of 8 cases

INTRODUCTION

Myxoid liposarcoma is the only translocation-associated liposarcoma subtype. It classically originates in the deep soft tissues of the thigh. At distal sites of the extremities, this tumor is exceedingly rare. We present a series of 8 cases occurring in the foot/ankle.

RESULTS

Two female and 6 male patients, aged between 32 and 77 years (mean, 54.3 years), were identified. Tumor size ranged from 1.1 to 10 cm (mean, 6.8 cm). Two lesions eroded bone. All tumors were treated by excision and 7 by (neo)adjuvant radiotherapy. R0 status was reached in 2 cases with 1 case followed by metastasis in the groin. All other cases were documented with R1 (n=2) or R2 (n=4) resection status. In 1 patient, the follow-up status was unknown. All other patients were alive 15-135 (mean, 55.8) months after initial diagnosis. We conclude that myxoid liposarcoma at acral sites are exceedingly rare, and in this series, prognosis was good irrespective of resection status. Clinicians and pathologists have to be aware because this sarcoma type shows a peculiar clinical behavior with high radio- and chemosensitivity and metastatic spread to extrapulmonary sites.

Pericytic mimicry in well-differentiated liposarcoma/atypical lipomatous tumor

Pericytes are modified smooth muscle cells that closely enwrap small blood vessels, regulating and supporting the microvasculature through direct endothelial contact. Pericytes demonstrate a distinct immunohistochemical profile, including expression of smooth muscle actin, CD146, platelet-derived growth factor receptor β, and regulator of G-protein signaling 5. Previously, pericyte-related antigens have been observed to be present among a group of soft tissue tumors with a perivascular growth pattern, including glomus tumor, myopericytoma, and angioleiomyoma. Similarly, malignant tumor cells have been shown to have a pericyte-like immunoprofile when present in a perivascular location, seen in malignant melanoma, glioblastoma, and adenocarcinoma. Here, we examine well-differentiated liposarcoma specimens, which showed some element of perivascular areas with the appearance of smooth muscle (n = 7 tumors). Immunohistochemical staining was performed for pericyte antigens, including smooth muscle actin, CD146, platelet-derived growth factor receptor β, and regulator of G-protein signaling 5. Results showed consistent pericytic marker expression among liposarcoma tumor cells within a perivascular distribution. MDM2 immunohistochemistry and fluorescence in situ hybridization for MDM2 revealed that these perivascular cells were of tumor origin (7/7 tumors), whereas double immunohistochemical detection for CD31/CD146 ruled out an endothelial cell contribution. These findings further support the concept of pericytic mimicry, already established in diverse malignancies, and its presence in well-differentiated liposarcoma. The extent to which pericytic mimicry has prognostic significance in liposarcoma is as yet unknown.

Mesenchymal tumours of the mediastinum--part I

The mediastinum is an anatomically defined space in which organs and major blood vessels reside with surrounding soft tissue elements. The thymus is an important organ in the mediastinum, and many of the masses encountered in the mediastinum are related to this organ. Most neoplasms diagnosed in the mediastinum are epithelial tumours (thymomas and thymic carcinomas), lymphomas or germ cell tumours. In contrast, soft tissue tumours of the mediastinum are rare. In 1963, Pachter and Lattes systematically reviewed soft tissue pathology of the mediastinum, covering the hitherto described [2, 226, 227] In this review, based on the 2013 WHO classification of soft tissue tumours and the 2015 WHO classification of tumours of the lung, pleura, thymus and heart, we provide an updated overview of mesenchymal tumours that may be encountered in the mediastinum.