MDM2 and CDK4 Immunostainings Are Useful Adjuncts in Diagnosing Well-Differentiated and Dedifferentiated Liposarcoma Subtypes

Primary pleomorphic liposarcoma of the spine. Case report and review of the literature

INTRODUCTION

To describe a single case, the fourth ever reported, of pleomorphic liposarcoma of the spine and to undertake a review of the literature.

PRESENTATION OF CASE

A 60 year old male patient had a bilateral lumbosciatica over a 3 month period. Imaging tests revealed a tumor mass in L1-L3 and a fracture in L2. Also, he had a mural thrombus both in the inferior vena cava and the left renal vein. The biopsy revealed a well-differentiated liposarcoma. En bloc resection of the lesion and stabilization was carried out. Due to the condition of the patient (hemodynamic instability, wound dehiscence and infection, and hypoproteinemia), a decision was made not to subject the patient to either radiation therapy or chemotherapy. The patient was subsequently found to suffer from myopathic paraparesis and a surgical wound infection. At three months, liver metastases were evident, as well as a recurrence of the lesion. A venous thrombosis that extended from the lower iliac vein to the right atrium was observed. The patient died from type I hepatorenal syndrome.

DISCUSSION

Pleomorphic liposarcoma of the spine is a rare occurrence. En bloc resection with wide margins is the treatment of choice. The use of radiotherapy in the spine is controversial. The role that should be played by chemotherapy is still unclear, although it has been employed in treatments.

CONCLUSION

In spite of treatment, these tumors lead to a poor prognosis, with high rates of recurrence, metastasis, and mortality.

The Role of MDM2 Amplification and Overexpression in Tumorigenesis

Mouse double minute 2 (MDM2) is a critical negative regulator of the tumor suppressor p53, playing a key role in controlling its transcriptional activity, protein stability, and nuclear localization. MDM2 expression is up-regulated in numerous cancers, resulting in a loss of p53-dependent activities, such as apoptosis and cell-cycle arrest. Genetic amplification and inheritance of MDM2 promoter single-nucleotide polymorphisms (SNPs) are the two best-studied mechanisms for up-regulating MDM2 activity. This article provides an overview of these events in human cancer, highlighting the frequent occurrence of MDM2 amplification in sarcoma and the role of SNP309 and SNP285 in regulating MDM2 expression and cancer risk. The availability of large-scale genomic profiling datasets, like those from The Cancer Genome Atlas Research Network, have provided the opportunity to evaluate the consequences of MDM2 amplification and SNP inheritance across high-quality tumor samples from diverse cancer indications.

Diagnostically Challenging Spindle Cell Neoplasms of the Retroperitoneum

The diagnostic spectrum of spindle cell neoplasms arising in the retroperitoneum is wide and, in the presence of commonly shared morphologic features, it may be challenging to establish a correct diagnosis in certain cases. Beyond seemingly undifferentiated spindle cell morphology, most neoplasms may reveal distinctive adipocytic, smooth muscle or myofibroblastic or nerve sheath differentiation and show additional diagnostic clues or characteristic molecular abnormalities. Obtaining sufficient and representative biopsy material, a thorough work-up, and extensive sampling of gross specimens followed by a combined histopathologic, immunohistochemical, and, if necessary, molecular work-up of these cases is advisable so as not to miss important diagnostic and/or prognostic indicators.

Intravenous leiomyomatosis: an unusual intermediate between benign and malignant uterine smooth muscle tumors

Intravenous leiomyomatosis is an unusual smooth muscle neoplasm with quasi-malignant intravascular growth but a histologically banal appearance. Herein, we report expression and molecular cytogenetic analyses of a series of 12 intravenous leiomyomatosis cases to better understand the pathogenesis of intravenous leiomyomatosis. All cases were analyzed for the expression of HMGA2, MDM2, and CDK4 proteins by immunohistochemistry based on our previous finding of der(14)t(12;14)(q14.3;q24) in intravenous leiomyomatosis. Seven of 12 (58%) intravenous leiomyomatosis cases expressed HMGA2, and none expressed MDM2 or CDK4. Colocalization of hybridization signals for probes from the HMGA2 locus (12q14.3) and from 14q24 by interphase fluorescence in situ hybridization (FISH) was detected in a mean of 89.2% of nuclei in HMGA2-positive cases by immunohistochemistry, but in only 12.4% of nuclei in negative cases, indicating an association of HMGA2 expression and this chromosomal rearrangement (P=8.24 × 10(-10)). Four HMGA2-positive cases had greater than two HMGA2 hybridization signals per cell. No cases showed loss of a hybridization signal by interphase FISH for the frequently deleted region of 7q22 in uterine leiomyomata. One intravenous leiomyomatosis case analyzed by array comparative genomic hybridization revealed complex copy number variations. Finally, expression profiling was performed on three intravenous leiomyomatosis cases. Interestingly, hierarchical cluster analysis of the expression profiles revealed segregation of the intravenous leiomyomatosis cases with leiomyosarcoma rather than with myometrium, uterine leiomyoma of the usual histological type, or plexiform leiomyoma. These findings suggest that intravenous leiomyomatosis cases share some molecular cytogenetic characteristics with uterine leiomyoma, and expression profiles similar to that of leiomyosarcoma cases, further supporting their intermediate, quasi-malignant behavior.

Histological Classification and Immunohistochemical Evaluation of MDM2 and CDK4 Expression in Canine Liposarcoma

Canine liposarcoma is an uncommon soft tissue sarcoma usually arising in the subcutis. While liposarcoma classification in dogs is based solely on histology, in humans it depends on the detection of genetic abnormalities that can lead to specific protein overexpression. This study is an immunohistochemical evaluation of MDM2 and CDK4 expression in canine liposarcoma designed to assess the correlation of these proteins with histologic type, grade, mitotic index and Ki67 labeling index and evaluate their utility in improving tumor classification. Fifty-three liposarcomas were retrospectively collected: 24 were well differentiated liposarcomas (WDL), 16 of which expressed MDM2 and 21 CDK4; 7 were myxoid liposarcomas (ML), 1 of which expressed MDM2 and 5 expressed CDK4; 18 were pleomorphic liposarcomas (PL), all were MDM2 negative and 12 expressed CDK4. Four tumors were morphologically consistent with dedifferentiated liposarcoma (DDL) a subtype described only in humans: 3 expressed MDM2 and 4 expressed CDK4. MDM2 expression correlated with histotype (highly expressed in WDL and DDL) and grade (highly expressed in grade 1 tumors). Histotype correlated with the Ki67 labeling index (lowest in WDL and highest in DDL). A revised classification, considering MDM2 expression, allowed 8 WDL to be reclassified as PL and correlated significantly with mitotic and Ki67 labeling index (both significantly lower in WDL and progressively higher in ML and DDL). These results partially parallel data reported for human liposarcomas, suggesting that WDL and DDL are distinct neoplastic entities characterized by MDM2 expression, which may represent a useful diagnostic and potentially prognostic marker for canine liposarcoma.

Liposarcoma masquerading as an inflammatory pseudotumor: a case report

BACKGROUND

Distinguishing an atypical lipomatous tumor/well-differentiated liposarcoma from a benign lipomatous tumor on morphology alone can be difficult and there is an established role for MDM2 fluorescent in situ hybridization studies in making this differential diagnosis. There is no literature on the role for MDM2 fluorescent in situ hybridization studies in distinguishing between a well-differentiated liposarcoma with extreme fibrosis and a fibrosing inflammatory pseudotumor.

CASE PRESENTATION

We report the case of a 76-year-old Australian woman initially diagnosed by an excision biopsy with a retroperitoneal fibrosing inflammatory pseudotumor. She was then diagnosed 5 years later with a pleomorphic undifferentiated sarcoma. Upon review of the original resection specimen, we were able to show that the tumor demonstrated MDM2 amplification. MDM2 amplification was also present in some adjacent bland adipose tissue, and also in the tumor recurrence as a pleomorphic undifferentiated sarcoma.

CONCLUSION

Taken together, our findings provide strong evidence that the original tumor was a misdiagnosed well-differentiated liposarcoma with extreme fibrosis, and the pleomorphic undifferentiated sarcoma represented a recurrence of the same tumor with dedifferentiation.

Deregulation of dicer and mir-155 expression in liposarcoma

Liposarcoma (LPS) is the most common soft tissue sarcoma. It has been demonstrated that mir-155 was the most overexpressed miRNA in well-differentiated LPS(WDLPS)/dedifferentiated LPS (DDLPS). The aim of this study is to evaluate the involvement of Dicer, Drosha and mir-155 in development of LPS and their possible role in stratification of different histological subtypes. Dicer, Drosha and mir-155 mRNA levels were analyzed in formalin-fixed paraffin-embedded specimens from patients diagnosed with 62 LPS and compared with samples of adipose tissues of healthy donors. The experimental data were obtained using qRT-PCR comparing Dicer, Drosha and mir-155 expression levels in tumor samples versus normal fat. The tumor samples from LPS patients showed a significantly lower Dicer expression versus normal adipose tissue, while Drosha levels did not differ. Concerning mir155 expression levels, our results demonstrated a significant mir-155 up-regulation in all LPS subtypes versus normal adipose tissue except for WDLS. These findings demonstrate for the first time that Dicer is deregulated in LPS and show that mir-155 is differentially expressed in LPS subgroups and it could be a promising tool to improve LPS disease stratification and differential diagnosis.

MDM2/CDK4 gene amplification in large/deep-seated 'lipomas': incidence, predictors and clinical significance

This study of 140 cases assessed the incidence of MDM2/CDK4 gene amplification in lipomatous neoplasms with histological features of a lipoma but which were of clinical concern due to large size (≥50 mm) and/or deep-seated (subfascial) location. Univariate and multivariate statistical analyses were used to identify clinical, radiological and pathological predictors of gene amplification. Differences in local recurrence rates between amplified and non-amplified cases were assessed using survival analysis. The findings indicate that the incidence of MDM2/CDK4 amplification in this setting is low at 5% (95%CI 1.4-8.6%). Variables associated with amplification on univariate analysis were tumour site (thigh, p = 0.004), size (>100 mm, p = 0.033) and presence of equivocal atypia (p = 0.001). Independent predictors on multivariate analysis were size (OR 3.9, 95%CI 1.4-11.3, p = 0.012) and presence of equivocal atypia (OR 12.5, 95%CI 1.9-80.3, p = 0.008). There was no significant difference in local recurrence rates between amplified and non-amplified cases (p = 0.461) based on a median follow-up time of 31 months. Assessment for MDM2/CDK4 amplification, therefore, should be considered in 'lipomas' which are >100 mm in size, show equivocal atypia and arise in the thigh. However, the clinical significance of gene amplification in this setting is unclear and requires confirmation in larger studies.

Gross examination and reporting of soft tissue tumours: evaluation of compliance with the UK Royal College of Pathologists soft tissue sarcoma dataset

Aims

Soft tissue tumours are a heterogeneous group of neoplasms that can arise at almost every anatomical site. As they often show similar clinical and radiological findings, histology is the definitive diagnostic method and it is crucial that the surgical pathology report contains accurate, useful information for management and prognostication. The soft tissue sarcoma minimum dataset produced by the Royal College of Pathologists in the UK outlines a structure for handling and reporting soft tissue tumours, including the core data required, and aiding pathologists in forming a consistent reporting approach.

Methods

We assessed the information in surgical pathology reports for soft tissue lesions at a tertiary soft tissue centre, in 1 year prior to the development of this dataset, and 1 year after its release, to audit the comparative adequacy of macroscopic and microscopic information provided, and to assess for differences in reporting since the advent of routine ancillary molecular diagnostic testing.

Results and conclusions

We found that while essential information was always included in reports, more specific details contributing to better quality reports such as more detailed macroscopic descriptions and a higher proportion of clinical summaries with radiological correlation were included in 2011 than 2006, despite increasing workload. Specimen handling, particularly of core biopsies, was also improved, reflecting the increasing need to conserve the maximum amount of patient material for molecular investigations.

Heterologous Liposarcomatous Differentiation in Malignant Phyllodes Tumor is Histologically Similar but Immunohistochemically and Molecularly Distinct from Well-differentiated Liposarcoma of Soft Tissue

Malignant phyllodes tumor (PT) infrequently displays heterologous differentiation, and when present is most often liposarcomatous. We identified five cases of malignant PT with regions identical to well-differentiated liposarcoma (WDLS) of soft tissue and evaluated them for MDM2 and CDK4 gene expression and amplification using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH), respectively. Despite indistinguishable morphology all cases of malignant PT with WDLS-like liposarcomatous differentiation were negative for MDM2 and CDK4 IHC and FISH, supporting different underlying pathogenesis.

The Current Status of Solitary Fibrous Tumor: Diagnostic Features, Variants, and Genetics

Solitary fibrous tumor (SFT) is a fibroblastic mesenchymal tumor originally described in the pleura but now shown at almost every anatomic site. Histopathologically, SFT is characteristically a circumscribed neoplasm composed of variably cellular and patternless distributions of bland spindle and ovoid cells within prominent collagenous stroma and shows diffuse expression of CD34, but it has a broad spectrum of both morphology and of biologic behavior. Many different names (particularly hemangiopericytoma) were previously used in the course of our understanding of this neoplasm but are now subsumed under the term "SFT," and the putative cell of origin was debated. However, it is now recognized that SFT is a translocation-associated neoplasm, consistently associated with NAB2-STAT6 gene fusions arising from recurrent intrachromosomal rearrangements on chromosome 12q, and this translocation is a likely major contributor to its pathogenesis. While most SFT with classical morphologic features behave in an indolent manner and those with overtly malignant histologic features tend to be aggressive neoplasms that behave as high-grade sarcomas, the behavior of SFT is unpredictable, and it is important to be aware of the propensity for aggressive behavior in a minority of histologically classical SFT and to ensure adequate clinical follow-up. Surgical excision remains the treatment gold standard; while radiotherapy and conventional chemotherapeutic agents have only shown limited efficacy, further understanding of the molecular events underlying tumorigenesis may allow the development of novel targeted treatments. We review SFT, discussing the morphologic spectrum and variants, including malignant and dedifferentiated subtypes, clinicopathological aspects, recent molecular genetic findings, and the differential diagnosis.

Patient With Slow-Growing Mediastinal Mass Presents With Chest Pain and Dyspnea

A 52-year-old white woman presented with severe pain over the right upper abdomen and nonpleuritic, right-sided, lower chest-wall pain. Her pain had progressively gotten more frequent and severe over the last 5 months. It was also associated with a nonexertional, pressure-like sensation in the central chest. The patient denied any shortness of breath, fevers, cough, or any sputum production. She was taking levothyroxine for hypothyroidism and was a 30-pack-year current smoker; there was no history of drug abuse or occupational exposure. Previous chest radiographs dating back to 5 years consistently showed an elevated right-sided hemidiaphragm without any infiltrates or effusions; cardiomediastinal structures were unremarkable. She had not had a previous workup for these abnormal findings.

Dedifferentiated Liposarcoma: Updates on Morphology, Genetics, and Therapeutic Strategies

Well-differentiated liposarcoma (WDL) and dedifferentiated liposarcoma (DDL) form the largest subgroup of liposarcomas, and represent a morphologic and behavioral spectrum of 1 disease entity, which arises typically in middle to late adult life, most frequently within the retroperitoneum or extremities. DDL is defined as nonlipogenic sarcoma that is juxtaposed to WDL, occurs as a recurrence of WDL or which can arise de novo, and typically has the appearance of undifferentiated pleomorphic or spindle cell sarcoma. DDL have a propensity for local recurrence, whereas distant metastasis is rarer, and behavior is related to anatomic site, with retroperitoneal neoplasms showing a significantly worse prognosis. Surgical resection remains the mainstay of treatment, and medical options for patients with aggressive recurrent or metastatic disease are limited. DDL share similar genetic abnormalities to WDL, with high-level amplifications of chromosome 12q14-15, including the MDM2 and CDK4 cell cycle oncogenes, and DDL harbor additional genetic changes, particularly coamplifications of 6q23 and 1p32. Novel therapies targeted at the gene products of chromosome 12 are being tested in clinical trials. We review the pathology and genetics of DDL, discussing morphologic patterns, immunohistochemical and genetic findings, the differential diagnosis, and future therapeutic strategies.

Giant Scrotal Fibrolipoma

Fibrolipoma, an infrequent histological subtype of lipoma, is considered a benign mesenchymal neoplasm. Fibrolipoma of the scrotum is an even more rare entity. We report a case of a 55-year-old male complaining for a slow-growing, painless mass in his left hemis-crotum. Imaging with ultrasonography and magnetic resonance imaging was inconclusive regarding the nature of the tumor and the tumor was excised, sparing the testis. The surgical specimen was a well-defined, yellowish white, solid, and firm mass, measuring 19.5×7×5 cm. There was no cytological atypia or mitosis and no lipoblasts recognized. On immunohistochemistry, MDM2 and CDK4 were not expressed. The histopathology report was fibrolipoma of the scrotum. To the best of our knowledge, this is only the fourth case of fibrolipoma originating from the scrotal components, spermatic cord or testis that has been reported in the English literature.

Prognostic value of HMGA2, CDK4, and JUN amplification in well-differentiated and dedifferentiated liposarcomas

HMGA2, CDK4, and JUN genes have been described as frequently coamplified with MDM2 in atypical lipomatous tumor, well-differentiated liposarcoma, and dedifferentiated liposarcoma. We studied the frequency of amplification of these genes in a series of 48 dedifferentiated liposarcomas and 68 atypical lipomatous tumors/well-differentiated liposarcomas. We correlated their amplification status with clinicopathological features and outcomes. Histologically, both CDK4 (P=0.007) and JUN (P=0.005) amplifications were associated with dedifferentiated liposarcoma, whereas amplification of the proximal parts of HMGA2 (5'-untranslated region (UTR) and exons 1-3) was associated with atypical lipomatous tumor/well-differentiated liposarcoma (P=0.01). CDK4 amplification was associated with axial tumors. Amplification of 5'-UTR and exons 1-3 of HMGA2 was associated with primary status and grade 1. Shorter overall survival was correlated with: age >64 years (P=0.03), chemotherapy used in first intent (P<0.001), no surgery (P=0.003), grade 3 (P<0.001), distant metastasis (P<0.001), node involvement (P=0.006), and CDK4 amplification (P=0.07). In multivariate analysis, distant metastasis (HR=8.8) and grade 3 (HR=18.2) were associated with shorter overall survival. A shorter recurrence-free survival was associated with dedifferentiated liposarcoma (P<0.001), grade 3 (P<0.001), node involvement (P<0.001), distant metastasis (P=0.02), recurrent status (P=0.009), axial location (P=0.001), and with molecular features such as CDK4 (P=0.05) and JUN amplification (P=0.07). Amplification of 5'-UTR and exons 1-3 (P=0.08) and 3'-UTR (P=0.01) of HMGA2 were associated with longer recurrence-free survival. Distant metastasis was associated with shorter recurrence-free survival (HR=5.8) in multivariate analysis. Dedifferentiated liposarcoma type was associated with axial location, grade 3 and recurrent status. In conclusion, we showed that the amplification of HMGA2 was associated with the atypical lipomatous tumor/well-differentiated liposarcoma histological type and a good prognosis, whereas CDK4 and JUN amplifications were associated with dedifferentiated liposarcoma histology and a bad prognosis. In addition, we also provided the first description of the molecular evolution of a well-differentiated liposarcoma into four successive dedifferentiated liposarcoma relapses, which was consistent with our general observations.

p16 Expression in Fat Necrosis

Distinguishing well-differentiated liposarcoma (WDL) from lipoma is of clinical and prognostic importance, but can be difficult on imaging and histology alone. WDL characteristically harbor amplifications of the MDM2 and CDK4 cell cycle oncogenes and overexpress the cell cycle regulator p16. Fluorescence in situ hybridization (FISH) to assess for MDM2 and CDK4 gene amplification is the diagnostic gold standard, and immunohistochemistry for the overexpressed MDM2 and CDK4 proteins is also useful but may not be routinely offered by pathology laboratories. p16 immunohistochemistry is a sensitive marker for WDL and is in the repertoire of most laboratories, and it has been suggested as a useful method of distinguishing WDL from lipomas when other ancillary modalities are not readily available. We describe a case of a large retroperitoneal adipocytic mass occurring in a 27-year-old male, which was clinically and radiologically in keeping with WDL. Histologically this was a differentiated adipocytic neoplasm with prominent fibrous septa and fat necrosis, more suggestive of retroperitoneal lipoma. Immunohistochemistry showed diffuse, strong nuclear expression of p16 in the areas of fat necrosis. However, CDK4 was negative and the lesion lacked evidence of MDM2 amplification with FISH. Diffuse expression of p16 in areas of fat necrosis in large or deep lipomas highlights the potential for diagnostic misinterpretation as well differentiated liposarcoma, and we therefore emphasize that p16 immunohistochemistry should always be interpreted as part of a panel with CDK4 +/− MDM2 in the differential diagnosis of WDL and lipoma.

Immunohistochemical expression of p16 in lipoblastomas

Lipoblastoma (LB) is a rare benign adipocytic tumor of childhood occasionally showing histological similarities to myxoid liposarcoma (ML) or well-differentiated liposarcoma (WDL). p16 immunohistochemistry has proved to be useful in distinguishing various types of liposarcomas, in particular WDL from lipoma, with higher sensitivity and specificity than MDM2 and CDK4 immunohistochemistry. In this study, we reported the histologic features of a series of 30 LB with emphasis on the potential diagnostic pitfalls and investigated the immunohistochemical expression of p16. Moreover, p16 immunostaining was performed in 16 liposarcomas (11 WDL and 5 ML), 16 lipomas, and 16 cases of liponecrosis in order to evaluate its usefulness in the differential diagnosis of challenging lesions occurring in older children. Overall, p16 immunostaining was positive in 3 LBs and in 12 out of 16 liposarcomas (10 WDL and 2 ML), with a sensitivity of 75%, a specificity of 90%, a positive predictive value of 80%, and a negative predictive value of 87%. All lipomas were p16 negative, whereas 5 liponecroses were positive. Accounting altogether the benign lesions versus liposarcomas, p16 showed a sensitivity of 75%, a specificity of 87%, a positive predictive value of 60%, and a negative predictive value of 93%. Our data suggest that a negative p16 immunostaining may be helpful in excluding a liposarcoma when occurring in unusual clinical contexts, such as in adolescence or late recurrence. However, such finding should be interpreted with caution since also some liposarcomas lack p16 and occasional LBs are positive.

Successful combination chemotherapy for metastatic inflammatory myofibroblastic tumor: A case report

A 64-year-old male presented with increased abdo-minal fullness and fever. Radiological examination revealed moderate ascites, a tumor with a diameter of 12.5 cm in the mesenteric region, as well as multiple tumors in the thoracic and abdominal para-aortic regions and in the left supraclavicular regions. Pathohistological findings of the biopsy specimen revealed atypical spindle cells accompanied by infiltration of lymphocytes. The plasmacytes were positive for CD68, murine double minute 2 and S-100, while they were negative for α-smooth muscle actin, cyclin-dependent kinase 4 and anaplastic lymphoma kinase. Clinically, the patient presented systemic symptoms and laboratory results indicated an elevation in the inflammatory response, while the CT and MRI findings were consistent with an inflammatory myofibroblastic tumor (IMT). Based on the clinical and histological findings, the patient was diagnosed with IMT. In total, 4 cycles of combination chemotherapy with doxorubicin and ifosfamide were administered. Tumor size reduction by 50% was achieved subsequent to the 4th chemotherapy cycle. In conclusion, successful control of this rare metastatic IMT was achieved by systemic chemotherapy.

Evaluation of Molecular and Immunohistochemical Adjunct Modalities in the Diagnosis of Soft Tissue Neoplasms

The accurate diagnosis of soft tissue neoplasms has crucial therapeutic and prognostic importance. There is frequent morphologic overlap between entities, and ancillary modalities are used in the vast majority of diagnoses. Immunohistochemistry is rapid and inexpensive, and in addition to the older markers that mainly detected cytoplasmic proteins, antibodies can indirectly detect tumor-specific genetic and molecular abnormalities. The use of molecular diagnostic techniques is now widespread, with molecular services often integrated into routine histopathology laboratories; as their cost and turnaround times begin to parallel those for immunohistochemistry, we compared the usefulness of ancillary immunohistochemistry, molecular genetic, and molecular cytogenetic techniques in the diagnosis of soft tissue lesions. We evaluated the number and contribution of immunohistochemical tests and panels and of ancillary molecular techniques in the primary histopathologic diagnosis of 150 soft tissue lesions. Ninety of 150 cases required either only one immunohistochemical panel or minimal immunohistochemistry for diagnosis, while 39/150 required 2 to 4 panels. In 5/150, ancillary molecular tests alone (without immunohistochemistry) were diagnostically sufficient. The majority of cases required one immunohistochemical panel for diagnosis, with a smaller proportion requiring a second, and a minority requiring a third or fourth (which mainly comprised neoplasms for which the final diagnosis was uncertain). Certain neoplasms required both extensive immunohistochemistry and ancillary molecular testing, despite which the final diagnosis was inconclusive. Ancillary molecular techniques now make a significant contribution to soft tissue tumor diagnosis, being required in over one third (52/150) of cases, and were useful in confirming or excluding tumors that were not possible to conclusively diagnose with histology and immunohistochemistry. Only a small proportion of soft tissue neoplasms (16/150; all benign) did not require immunohistochemistry or ancillary molecular methods, with morphology alone being sufficient for diagnosis.

Approach and management of a giant lipoma in the left lumbar region

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We present a case of giant lipoma in the left lumbar region.

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Movements were hindered, especially rotation, flexion and extension of the trunk.

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The size of the bulk presents differential diagnostic problems with liposarcoma.

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Surgical excision was performed to confirm diagnosis with histological evaluation.

Introduction

Lipomas are the most common benign tumors of the adipose tissue and can be located in any region of the body. In most cases lipomas are small and asymptomatic, but they can at times reach considerable dimensions and, depending on their anatomic site, hinder movements, get inflamed, cause lymphedema, pain and/or a compression syndrome.

Presentation of case

We here report the case of an otherwise healthy patient who came to our observation with a giant bulk in the left lumbar region which had been showing progressive growth in the previous 5–6 years. Physical examination, ultrasound and MRI were carried out in order to characterize the size, vascularization and limits of the lesion. Due to the pain and restriction of movement that this bulky lesion caused, surgical excision of the lesion was performed.

Discussion

Giant lipomas display an important differential diagnosis problem with malignant neoplasms, especially liposarcomas, with which they share many features; often the final diagnosis rests on histological evaluation. We here discuss the diagnostic problems that arise with a giant lipoma and all the possible approaches concerning treatment of such a big lesion, explaining the reasons of our approach and management of a common tumor in our case presenting unusual dimensions and location.

Conclusion

Our approach revealed to be successful in order to nurse our patient's pain, restore the mobility and address the aesthetic issues that this lesion caused. Postoperative checkups were carried out for one year and no signs of relapse have been reported.

Gankyrin is a predictive and oncogenic factor in well-differentiated and dedifferentiated liposarcoma

Liposarcoma is one of the most common histologic types of soft tissue sarcoma and is frequently an aggressive cancer with poor outcome. Hence, alternative approaches other than surgical excision are necessary to improve treatment of well-differentiated/dedifferentiated liposarcoma (WDLPS/DDLPS).

For this reason, we performed a two-dimensional gel electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-time of flight mass spectrometry/mass spectrometry (MALDI-TOF/MS) analysis to identify new factors for WDLPS and DDLPS. Among the selected candidate proteins, gankyrin, known to be an oncoprotein, showed a significantly high level of expression pattern and inversely low expression of p53/p21 in WDLPS and DDLPS tissues, suggesting possible utility as a new predictive factor. Moreover, inhibition of gankyrin not only led to reduction of in vitro cell growth ability including cell proliferation, colony-formation, and migration, but also in vivo DDLPS cell tumorigenesis, perhaps via downregulation of the p53 tumor suppressor gene and its p21 target and also reduction of AKT/mTOR signal activation. This study identifies gankyrin, for the first time, as new potential predictive and oncogenic factor of WDLPS and DDLPS, suggesting the potential for service as a future LPS therapeutic approach.

[Liposarcoma of the spermatic cord]

The paper reviews the literature on primary paratesticular tumors. It describes the classification, brief characteristics of liposarcomas and the morphological pattern of the tumor with an immunohistochemical profile. A clinical case of differentiated liposarcoma of the spermatic cord with myxoid and rhabdomyoblastic differentiation is depicted in a 61-year-old man.

Multiple spinal metastases from a well-differentiated liposarcoma of the iliac wing: a case report

STUDY DESIGN

A case report.

OBJECTIVES

To report an unusual case of multiple spinal metastases from an undiagnosed well-differentiated liposarcoma (WDLPS) of the iliac wing and to stress the need of a meticulous clinical examination and further screening of patients with chronic and asymptomatic bony lesions.

SETTING

University of medicine of Monastir, Department of neurological surgery, Fattouma Bourguiba University Hospital, Monastir, Tunisia and University of Medicine of Tunis EL Manar, Department of neurological surgery, Tunisian National Institute of Neurology, Tunis, Tunisia.

METHODS

A 39-year-old man presented with signs of spinal cord compression for the past 2 weeks. His medical history was consistent for an asymptomatic right iliac wing mass that appeared 3 years ago and for which he has not consulted. Magnetic resonance imaging revealed multiple bony lesions of the thoraco-lumbar spine associated with a 6-cm right paravertebral mass at the T4 level extending posteriorly through the intervertebral foramina to the spinal canal causing major spinal cord compression. An emergent T2-T6 laminectomy allowed for a complete resection of the epidural mass. Pathological examination confirmed the diagnosis of well-differentiated liposarcoma. Adjunctive radiation therapy was administered.

RESULTS

The patient's neurological status improved remarkably under an intensive care and rehabilitation program. He was ambulatory without assistance in the second postoperative week.

CONCLUSION

The case reported in this paper represents a genuine example of the possible metastatic potential of WDLPSs of the bone and underscores the importance of examining patients thoroughly, especially when they have chronic and asymptomatic lesions.

Squamous Cell Carcinoma Arising From Massive Localized Lymphedema of Scrotum Mimicking Scrotal Smooth Muscle Hamartoma of Dartos: A Case Report

Massive localized lymphedema (MLL) is an uncommon benign skin lesion typically presenting with prominent edema and vascular proliferation in the adipose tissue of lower limbs. When rarely occurring in scrotum, it instead is characterized by a striking proliferation of dermal smooth muscle bundles mimicking acquired smooth muscle hamartoma of dartos. The authors report a rare case of scrotal MLL. A 57-year-old obese man with a history of previous surgery for rectal adenocarcinoma, 20 years earlier, presented with progressive nodular enlargement of the scrotum for 2 years, causing discomfort, difficulty in ambulation, and cosmetic problems. The preoperative radiographic investigation revealed thickening of the scrotal wall with multiple soft-tissue nodules. The patient underwent a wide excision of the scrotal wall, perineum, and penile skin. The pathological examination showed a scrotal MLL associated with well-differentiated squamous cell carcinoma. The authors speculate that prior radiotherapy and surgery together with morbid obesity led to long-standing lymphedema that triggered the proliferation of smooth muscle cells, chronic epidermal change, and finally squamous cell carcinoma.

Aplidin in patients with advanced dedifferentiated liposarcomas: a French Sarcoma Group Single-Arm Phase II study

BACKGROUND

Preclinical data have suggested a therapeutic role of JUN pathway activation in dedifferentiated liposarcoma (DDLPS) tumorigenesis. Aplidin is a drug inducing apoptosis through a strong, sustained activation of c-Jun NH2-terminal kinase.

METHODS

This phase II trial included patients with progressive advanced DDLPS. They received Aplidin 5 mg/m(2) days 1-15, 28-day cycle until disease progression or unacceptable toxicity. The primary end point was the 3-month nonprogression rate (PFS3) defined as the proportion of patients with nonprogressive disease at 3 months. A PFS3 of 40% considered as a reasonable objective to claim drug efficacy.

RESULTS

Between August 2012 and May 2013, 24 patients were included. Sixteen had received prior chemotherapy. Twenty-two were assessable for efficacy. The PFS3 was 9.1% [95% confidence interval (CI) 1.1-29.2]. Median progression-free and overall survivals were 1.6 months (95% CI 1.4-2.6) and 9.2 months (95% CI 6.6-). The most frequent adverse events of any grade were nausea, fatigue, anorexia, vomiting and diarrhea.

CONCLUSION

Aplidin did not meet the primary end point of this trial and do not deserve further investigation in DDLPS.

CLINICALTRIALSGOV IDENTIFIER

NCT01876043.

Intimal sarcoma of the abdominal aorta with platelet-derived growth factor receptor α overexpression and amplification in mural invasive cells and pulmonary metastatic cells but not in intimal spreading cells

Intimal sarcoma (IS) is the most common sarcoma of the aorta. The platelet-derived growth factor receptor α (PDGFRA), murine double minute 2 (MDM2), and cyclin-dependent kinase 4 (CDK4) genes are often simultaneously amplified in IS. While immunohistochemical analysis of IS tissue has demonstrated frequent overexpression of the MDM2 and CDK4 proteins, the expression pattern of PDGFRA has not been well characterized, particularly in terms of intratumoral heterogeneity. Here, we present the case of a 46-year-old man who presented with a backache and was subsequently diagnosed with IS. Intratumoral heterogeneity of PDGFRA gene amplification was observed using fluorescence in situ hybridization and was positively correlated with PDGFRA protein expression using immunohistochemistry (IHC). The expression of PDGFRA was also correlated with cytological atypia: PDGFRA was not overexpressed in intimal spreading cells that displayed the lowest degree of atypia while PDGFRA overexpression and amplification were observed in invasive cells of progressive areas such as the aortic wall and a pulmonary metastatic site, which showed increased cytological atypia. Although PDGFRA has not been well examined on IHC, IHC of PDGFRA could be useful to diagnose IS. However, the areas within the tumor from which specimens are derived are important given potential intratumoral heterogeneity.

An update on the application of newly described immunohistochemical markers in soft tissue pathology

CONTEXT

During the last 5 to 10 years, significant progress has been made in the molecular characterization of soft tissue tumors, predominantly with the identification of recurrent translocations or amplification of certain genes in different tumor types. Alongside this, translational efforts have identified many novel and diagnostically useful immunohistochemical markers for many of these tumor types.

OBJECTIVE

This article reviews a select group of recently described immunohistochemical markers of particular use in the evaluation of mesenchymal neoplasms; the underlying biology of the protein product, practical utility, and limitations of each marker are discussed in detail.

DATA SOURCES

Literature review, authors' research data, and personal practice experience serve as sources.

CONCLUSIONS

There are many diagnostically useful immunohistochemical markers to help confirm the diagnosis of many different soft tissue tumor types, some of which have reduced the need for additional, and more costly, studies, such as fluorescence in situ hybridization. However, no one marker is 100% specific for a given tumor, and knowledge of potential pitfalls and overlap in patterns of staining among other tumor types is crucial to ensure the appropriate application of these markers in clinical practice.

Liposarcoma miRNA signatures identified from genome-wide miRNA expression profiling

AIMS

To identify the miRNA expression profile of liposarcoma (LPS) that could facilitate detection of LPS, and provide the basis for further investigation of molecular-targeted therapeutic drugs.

MATERIALS & METHODS

A real-time quantitative PCR assay was performed to analyze the expression of 1888 miRNAs from 25 LPS tumor tissue samples, 16 samples of adipose tissue adjacent to the tumors and 18 normal adipose tissue samples from patients with LPS.

RESULTS

Ten dysregulated miRNAs were identified that effectively distinguished LPS tissue from adipose tissue and benign lipoma tissue, and LPS tumor tissues from normal adipose tissues in LPS patients. Furthermore, the expression profiles of miRNAs could also classify the subtype of LPS.

CONCLUSION

The identified miRNAs appear to be novel biomarkers for the detection of LPS, and may contribute to an understanding of the mechanisms of LPS tumorigenesis and its development, and further elucidate the characteristics of LPS subtypes.

CDK4 Amplification Reduces Sensitivity to CDK4/6 Inhibition in Fusion-Positive Rhabdomyosarcoma

PURPOSE

Rhabdomyosarcoma (RMS) is the most common pediatric soft tissue sarcoma and includes a PAX3- or PAX7-FOXO1 fusion-positive subtype. Amplification of chromosomal region 12q13-q14, which contains the CDK4 proto-oncogene, was identified in an aggressive subset of fusion-positive RMS. CDK4/6 inhibitors have antiproliferative activity in CDK4-amplified liposarcoma and neuroblastoma, suggesting CDK4/6 inhibition as a potential therapeutic strategy in fusion-positive RMS.

EXPERIMENTAL DESIGN

We examined the biologic consequences of CDK4 knockdown, CDK4 overexpression, and pharmacologic CDK4/6 inhibition by LEE011 in fusion-positive RMS cell lines and xenografts.

RESULTS

Knockdown of CDK4 abrogated proliferation and transformation of 12q13-14-amplified and nonamplified fusion-positive RMS cells via G1-phase cell-cycle arrest. This arrest was mediated by reduced RB phosphorylation and E2F-responsive gene expression. Significant differences in E2F target expression, cell-cycle distribution, proliferation, or transformation were not observed in RMS cells overexpressing CDK4. Treatment with LEE011 phenocopied CDK4 knockdown, decreasing viability, RB phosphorylation, and E2F-responsive gene expression and inducing G1-phase cell-cycle arrest. Although all fusion-positive cell lines showed sensitivity to CDK4/6 inhibition, there was diminished sensitivity associated with CDK4 amplification and overexpression. This variable responsiveness to LEE011 was recapitulated in xenograft models of CDK4-amplified and nonamplified fusion-positive RMS.

CONCLUSIONS

Our data demonstrate that CDK4 is necessary but overexpression is not sufficient for RB-E2F-mediated G1-phase cell-cycle progression, proliferation, and transformation in fusion-positive RMS. Our studies indicate that LEE011 is active in the setting of fusion-positive RMS and suggest that low CDK4-expressing fusion-positive tumors may be particularly susceptible to CDK4/6 inhibition.

Molecular diagnostics in soft tissue sarcomas and gastrointestinal stromal tumors

Soft tissue sarcomas are rare malignant heterogenous tumors of mesenchymal origin with over fifty subtypes. The use of hematoxylin and eosin stained sections (and immunohistochemistry) in the morphologic assessment of these tumors has been the bane of clinical diagnosis until recently. The last decade has witnessed considerable progress in the understanding and application of molecular techniques in refining the current understanding of soft tissue sarcomas and gastrointestinal stromal tumors beyond the limits of traditional approaches. Indeed, the identification of reciprocal chromosomal translocations and fusion genes in some subsets of sarcomas with potential implications in the pathogenesis, diagnosis and treatment has been revolutionary. The era of molecular targeted therapy presents a platform that continues to drive biomarker discovery and personalized medicine in soft tissue sarcomas and gastrointestinal stromal tumors. In this review, we highlight how the different molecular techniques have enhanced the diagnosis of these tumors with prognostic and therapeutic implications.

Fluorescence In Situ Hybridization for MDM2 Amplification as a Routine Ancillary Diagnostic Tool for Suspected Well-Differentiated and Dedifferentiated Liposarcomas: Experience at a Tertiary Center

Background. The assessment of MDM2 gene amplification by fluorescence in situ hybridization (FISH) has become a routine ancillary tool for diagnosing atypical lipomatous tumor (ALT)/well-differentiated liposarcoma and dedifferentiated liposarcoma (WDL/DDL) in specialist sarcoma units. We describe our experience of its utility at our tertiary institute. Methods. All routine histology samples in which MDM2 amplification was assessed with FISH over a 2-year period were included, and FISH results were correlated with clinical and histologic findings. Results. 365 samples from 347 patients had FISH for MDM2 gene amplification. 170 were positive (i.e., showed MDM2 gene amplification), 192 were negative, and 3 were technically unsatisfactory. There were 122 histologically benign cases showing a histology:FISH concordance rate of 92.6%, 142 WDL/DDL (concordance 96.5%), and 34 cases histologically equivocal for WDL (concordance 50%). Of 64 spindle cell/pleomorphic neoplasms (in which DDL was a differential diagnosis), 21.9% showed MDM2 amplification. Of the cases with discrepant histology and FISH, all but 3 had diagnoses amended following FISH results. For discrepancies of benign histology but positive FISH, lesions were on average larger, more frequently in "classical" (intra-abdominal or inguinal) sites for WDL/DDL and more frequently core biopsies. Discrepancies of malignant histology but negative FISH were smaller, less frequently in "classical" sites but again more frequently core biopsies. Conclusions. FISH has a high correlation rate with histology for cases with firm histologic diagnoses of lipoma or WDL/DDL. It is a useful ancillary diagnostic tool in histologically equivocal cases, particularly in WDL lacking significant histologic atypia or DDL without corresponding WDL component, especially in larger tumors, those from intra-abdominal or inguinal sites or core biopsies. There is a significant group of well-differentiated adipocytic neoplasms which are difficult to diagnose on morphology alone, in which FISH for MDM2 amplification is diagnostically contributory.

Retroperitoneal liposarcoma: current insights in diagnosis and treatment

Retroperitoneal liposarcoma (RLS) is a rare, biologically heterogeneous tumor that present considerable challenges due to its size and deep location. As a consequence, the majority of patients with high-grade RLS will develop locally recurrent disease following surgery, and this constitutes the cause of death in most patients. Here, we review current insights and controversies regarding histology, molecular biology, extent of surgery, (neo)adjuvant treatment, and systemic treatment including novel targeted agents in RLS.

Immunohistochemistry in undifferentiated neoplasm/tumor of uncertain origin

CONTEXT

Immunohistochemistry has become an indispensable ancillary study in the identification and classification of undifferentiated neoplasms/tumors of uncertain origin. The diagnostic accuracy has significantly improved because of the continuous discoveries of tissue-specific biomarkers and the development of effective immunohistochemical panels.

OBJECTIVES

To identify and classify undifferentiated neoplasms/tumors of uncertain origin by immunohistochemistry.

DATA SOURCES

Literature review and authors' research data and personal practice experience were used.

CONCLUSIONS

To better guide therapeutic decisions and predict prognostic outcomes, it is crucial to differentiate the specific lineage of an undifferentiated neoplasm. Application of appropriate immunohistochemical panels enables the accurate classification of most undifferentiated neoplasms. Knowing the utilities and pitfalls of each tissue-specific biomarker is essential for avoiding potential diagnostic errors because an absolutely tissue-specific biomarker is exceptionally rare. We review frequently used tissue-specific biomarkers, provide effective panels, and recommend diagnostic algorithms as a standard approach to undifferentiated neoplasms.

Dedifferentiated liposarcoma involving the spleen and splenic hilum: a report of a case with a rare growth pattern

We present a rare case of dedifferentiated liposarcoma confined to the spleen and splenic hilum. An 81-year-old man was referred to our hospital with a large asymptomatic splenic tumor. The patient underwent splenectomy, and the adipose tissue surrounding the splenic hilum was also resected. Microscopically, the tumor mainly consisted of high-grade spindle cells similar to those seen in undifferentiated pleomorphic liposarcoma. In the splenic hilum, scattered atypical cells were detected in the sclerosing component and adipose tissue. Immunohistochemically, both the spindle cells in the spleen and the atypical cells in the splenic hilum were positive for MDM2 and CDK4. The histopathologic diagnosis was dedifferentiated liposarcoma derived from an atypical lipomatous tumor/well-differentiated liposarcoma of the adipose tissue in the splenic hilum with extension into the spleen. Dedifferentiated liposarcoma in the spleen and splenic hilum should be considered as a differential diagnosis of splenic tumors.

Prognostic relevance of Fédération Nationale des Centres de Lutte Contre le Cancer grade and MDM2 amplification levels in dedifferentiated liposarcoma: a study of 50 cases

Dedifferentiated liposarcoma represents a form of liposarcoma composed of a non-lipogenic sarcoma associated with well-differentiated liposarcoma. The prognostic significance of histological grading of the dedifferentiated component remains to be elucidated due to vague grading criteria employed in previous studies. Molecular markers of tumor behavior, including amplification levels of murine double minute-2 (MDM2) and cyclin-dependent kinase-4 (CDK4) genes, have been explored in a limited number of cases. Here we investigate whether 'Fédération Nationale des Centres de Lutte Contre le Cancer' (FNCLCC) grade and MDM2 gene amplification levels have prognostic value in dedifferentiated liposarcoma in terms of local recurrence and disease-specific survival. Fifty cases were retrieved, reviewed and FNCLCC grade was scored for the dedifferentiated component. Testing for MDM2 gene amplification was performed by fluorescence in situ hybridization. Amplification was categorized as high level (≥20 copies) and as low level (<20 copies). Follow-up data was obtained through chart review. Log-rank test and Cox proportional hazard models were used to determine the effect of grade and level of MDM2 amplification on outcomes. Our series includes 50 patients (male n=28, female n=22) with an average age of 63 years (range, 28-88) and a median follow-up of 28 months (range, 2-120). Tumors were graded as grade 1 (6%), grade 2 (58%), and grade 3 (36%). When adjusted for age, sex, site, tumor size, and margin status, grade 3 patients had a higher recurrence rate than grades 1 and 2 (HR=2.07, 95% CI: 1.24, 7.62; P=0.015). Patients with high-level MDM2 amplification had higher recurrence rate on univariate analysis (P=0.028), but not on multivariate analysis (HR=1.69, 95% CI: 0.73, 3.94; P=0.221). FNCLCC grade 3 dedifferentiation confers a worse prognosis in dedifferentiated liposarcoma in terms of local recurrence. MDM2 amplification level remains a useful diagnostic tool in dedifferentiated liposarcoma, but has no prognostic value in terms of local recurrence.

[Adipocytic tumors]

Adipocytic tumors are the most common mesenchymal neoplasms, liposarcoma accounting for approximately 20% of soft tissue sarcomas. The differential diagnosis between benign and malignant tumors is often problematic and represents a significant proportion of consultation cases. The goal of this article is to review liposarcoma subtypes, the main benign adipocytic neoplasms: lipoblastoma, hibernoma, spindle/pleomorphic cell lipoma, chondroid lipoma, as well as non adipocytic neoplasms with a lipomatous component such as lipomatous solitary fibrous tumor, emphasizing on practical differential diagnosis issues, and immunohistochemical and molecular tools allowing their resolution.

Orbital liposarcoma masquerading as a hemangioma

Liposarcomas are the most common soft tissue sarcomas in adulthood, comprising approximately 20% of all sarcomas; most present in the extremities and retroperitoneum (1). Despite the large amount of adipose tissue in the orbit, orbital liposarcomas are rare. Diagnosis can be challenging due to the rarity of the entity and the pathological similarity to benign adipose tumors (2, 3). Fortunately, the advent of immunohistochemical staining has aided in diagnosis. Management of orbital liposarcoma also can be challenging, as illustrated by the case described herein (4).

High-dose continuous-infusion ifosfamide in advanced well-differentiated/dedifferentiated liposarcoma

Background

Liposarcomas represent the most common histological type of soft-tissue sarcomas (STS). Its main subgroups, WD/DD, is known to be poorly sensitive to chemotherapy, with few active agents, i.e., anthracyclines +/- ifosfamide and trabectedin. High-dose ifosfamide (HDIFX >12 g/m2) is active in STS pts pretreated with standard-dose IFX, though with greater toxicity. A prolonged continuous-infusion (ci) through a portable external pump may be an alternative way to administer HDIFX.

Methods

From March 2002 to August 2013, 28 pts (median age =60, range =37–73 yrs) with advanced disease (6 WD and 22 WD/DD) were given ciHDIFX, at the dose of 14 g/m2 as a 14-day continuous infusion every 4 weeks. Twenty-four pts (86%) were previously treated with chemotherapy (19 with anthracyclines and ifosfamide; 4 with anthracycline monotherapy; 1 with trabectedin).

Results

Seven PR (all in DDLPS), 2 minor response (MR) and 11 SD were observed. Of interest, 6 of 9 patients with PR or MR had had SD with the previous therapy with anthracycline plus ifosfamide. The median progression-free survival was 7 months. Most common side effects were mild myelosuppression (anemia G2-3 in 3 pts; G2-3 neutropenia in 3 pts and G4 in 1; G3 thrombocytopenia in 1 pt); nausea (G3 in 3 pts) and fatigue (G3 in 6 pts). One pts had transient G3 confusion.

Conclusions

These data suggest that ciHDIFX is active in WD/DDLPS, even in patients already treated with a combination of anthracyclines plus ifosfamide. In this series, ciHDIFX regimen was better tolerated than HDIFX in published studies.

[Value of core needle biopsy in preoperative diagnostics of soft tissue tumors: possibilities and limitations]

The differential diagnosis of soft tissue swellings encompasses a variety of benign, intermediate, low-grade malignant and high-grade neoplastic lesions in addition to tumor-like reactive processes. As treatment of these heterogeneous conditions varies greatly from conservative observation and simple local excision up to extensive radical surgical resection, treatment decisions are based mainly on a precise preoperative histological diagnosis on limited biopsy material. Even for clinically unequivocal sarcomas, the importance of the preoperative histological diagnosis has been increasingly emphasized as different therapeutic regimens have been established for different sarcoma types and the indications for preoperative treatment is influenced by the tumor grade and by the entity itself. Other factors positively influencing the increasing use of core needle biopsy for preoperative tumor diagnosis in soft tissue pathology are the availability of modern high-resolution imaging modalities as well as the establishment of several new second generation immunohistochemical markers and the discovery of entity-specific translocations detected by fluorescence in situ hybridization (FISH) in several sarcoma subtypes. In this review it will be shown that a targeted approach for processing core needle biopsies oriented towards the characteristic topographical, demographic, cytomorphological and architectural features of soft tissue lesions facilitates a precise diagnosis of soft tissue neoplasms in most cases. However, profound knowledge of the different aspects of soft tissue tumor diagnostics and familiarity with the frequent as well as the less common and rare tumor entities and variants is a prerequisite for appropriate interpretation of core needle biopsy findings and for selecting a limited but well-suited marker panel. The utilization of modern immunohistochemistry and/or FISH methods is highly useful for establishing the diagnosis of rare and unusual neoplasms in core needle biopsies.

Mdm2 and p53 Expression in Radiation-Induced Sarcomas of the Head and Neck: Comparison with De Novo Sarcomas

Background

The pathogenesis of radiation-induced sarcomas (RISs) is not well known. In RIS, TP53 mutations are frequent, but little is known about Mdm2-p53 interaction, which is a recent therapeutic target of sarcomas.

Methods

We studied the immunohistochemical expression of Mdm2 and p53 of 8 RISs. The intervals between radiation therapy and diagnosis of secondary sarcomas ranged from 3 to 17 years.

Results

Mdm2 expression was more common in de novo sarcomas than RISs (75% vs 37.5%), and p53 expression was more common in RISs than in de novo cases (75% vs 37.5%). While half of the RISs were Mdm2(–)/p53(+), none of de novo cases showed such combination; while half of de novo sarcomas were Mdm2(+)/p53(–), which are a candidate group of Mdm2 inhibitors, only 1 RIS showed such a combination. Variable immunoprofiles observed in both groups did not correlate with tumor types, except that all of 2 myxofibrosarcomas were Mdm2(+)/p53(+).

Conclusions

In conclusion, we speculated that both radiation-induced and de novo sarcomagenesis are not due to a unique genetic mechanism. Mdm2-expression without p53 overexpression in 1 case of RIS decreases the future possibility of applying Mdm2 inhibitors on a subset of these difficult tumors.