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

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

Differential Diagnosis of Lipoma and Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma by Cytological Analysis

Background: Adipocytic tumors are the most common soft tissue tumors, with lipomas and atypical lipomatous tumor/well-differentiated liposarcomas (ALT/WDL) comprising the majority of cases. Preoperative differential diagnosis of lipoma or ALT/WDL can provide important information for decisions regarding treatment. We evaluated the cytological findings of 20 cases of lipoma and ALT/WDL.Methods: Fluorescence in situ hybridization (FISH) was performed on formalin-fixed paraffin-embedded specimens (FFPE) to examine mouse double minute 2 homolog (MDM2) amplification in all cases. Tissue samples were collected from the center of the surgical materials, stained with Papanicolaou, and evaluated for 12 cytological parameters by six cytotechnologists.Results: The findings regarding large atypical cells, multinucleated cells, and nuclear pleomorphism were highly concordant among the cytotechnologists and were associated with MDM2 amplification. Large atypical cells, considered a highly specific feature of ALT/WDL, were not observed in the lipoma cases. However, the sensitivity of the large atypical cell findings was not high (67%), and therefore, comprehensive evaluation of multinucleated cells and pleomorphism is crucial for predicting the diagnosis of ALT/WDL. FISH of MDM2 on Papanicolaou-stained specimens was performed in four cases. In two cases, the results were similar to those of MDM2 FISH performed on FFPE sections and were reproducible, whereas in two other cases, the signal could not be evaluated because of the strong background coloration. Conclusions: Cytology specimens may be useful for preoperative diagnosis of adipocytic tumors, particularly if the FISH conditions for Papanicolaou-stained specimens and the detection accuracy of MDM2 amplification can be improved.

A Scoring System Combining Clinical, Radiological, And Histopathological Examinations For Differential Diagnosis Between Lipoma And Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma

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

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

Background: Preoperative differential diagnosis between atypical lipomatous tumor (ALT)/well-differentiated liposarcoma (WDLS) and lipoma is important to determine the appropriate resection margin. However, since their radiological and histopathological findings are similar, it may be difficult to make a differential diagnosis. In this study, we evaluated the diagnostic accuracies of clinical, radiological, and histopathological examinations for diagnosing ALT/WDLS and developed a new combined scoring system.Methods: Eighty-nine ALT/WDLS and 56 lipomas were included and their clinical characteristics, magnetic resonance imaging (MRI) findings, histological findings by hematoxylin and eosin (HE) staining were investigated, and compared between ALT/WDLS and lipoma. Then, univariate analyses and multivariate logistic regression analyses were performed for the findings, and a combined scoring system consisted of predictive factors of ALT/WDLS was developed. Results: The univariate and multivariate logistic regression analyses revealed that tumor location (lower extremity), deep site, and size (>11cm), thick septa (>2mm), enhancement of septa or nodular lesions on MRI, and lipoblasts in HE staining were significantly different for the diagnosis of ALT/WDLS. Based on the six predictive factors, we developed a combined scoring system (total 0–16 points, the cutoff was 9 points). The mean score of ALT/WDLS was significantly higher than lipoma (11.9 vs. 5.6, p<0.0001). The area under the curve was 0.945, and sensitivity was 87.6% and specificity was 91.1% by the receiver operating characteristics curve.Conclusions: We developed a new combined scoring system based on comprehensive examinations that excluded examination which requires special equipment and reagents such as fluorescence in situ hybridization (FISH), and this can be used in many medical institutions. The diagnostic accuracy of ALT/WDLS was high and it may be useful for preoperative diagnosis and surgical plan.

Recent Advancement in Atypical Lipomatous Tumor Research

After Evans and colleagues identified the lipomatous tumor with a well-differentiated liposarcoma in a subcutaneous location or within a muscle layer, namely, atypical lipomatous tumor (ALT), this malignancy has been investigated to clarify the characteristics of clinical behavior and genomic changes. As one of the important issues for clinicians, it is a hot topic of how to distinguish ALT from benign lipoma in the clinical aspect. Recent studies revealed novel findings to clarify the risk factor for the diagnosis of ALT and molecular targets for the treatment of ALT. Clinical characteristics of superficial-type ALT well reflect the subcutaneous location of the tumor and are slightly different compared to deep-type ALT, such as tumor size. In addition, there has been a recent discovery of novel findings in ALT-related genes, namely, HMG2A (high mobility group protein 2a), YEATS4 (YEATS domain containing 4), and CPM (Carboxypeptidase M). Recent updates on treatment for advanced ALT are well developed including immunotherapy and conducting clinical trials. Finally, this review introduces one of the hot topics of ALT research focused on epigenetic changes: their attention in recent updates on clinical characteristics and the novel discovery of related genes, treatment, and epigenetic modifications in atypical lipomatous tumors.

Giant Atypical Lipomatous Tumor of Posterior Mediastinum In Adolescent ：A Case Study and the Literature Review​

Background: It is usually common for liposarcoma as one of the soft tissue sarcomas to be found in adults, and the disease in children is the rare case. Case presentation: This article involves in a 14-year-old boy with a primary posterior mediastinal atypical lipomatous tumor. It also provides a literature review and summary for the disease with the aim of making the disease well learned, because of the absence of the uniform standards for the clinical features, diagnostic methods, best treatment methods, and clinical efficacy of the atypical lipomatous tumor.Conclusion: Complete surgical resection is the best method for the eradication of tumors. However, mediastinal liposarcoma can not be completely removed by surgery in some cases. For the treatment of residual tumor tissue, molecular inhibitors will be an important supplementary method for the treatment of liposarcoma in the future.