Lipoma Research Articles

Recurrent 8q11-13 Aberrations Leading to PLAG1 Rearrangements, Including Novel Chimeras HNRNPA2B1::PLAG1 and SDCBP::PLAG1, in Lipomatous Tumors.

Structural abnormalities of chromosome bands 8q11-13, resulting in rearrangement of the pleomorphic adenoma gene 1 (PLAG1), are known to characterize lipoblastoma, a benign fat cell tumor, found mainly in children. Here, we describe 8q11-13 rearrangements and their molecular consequences on PLAG1 in 7 lipomatous tumors in adults. The patients were 5 males and 2 females between 23 and 62 years old. The tumors, namely five lipomas, one fibrolipoma and one spindle cell lipoma, were examined using G-banding with karyotyping, fluorescence in situ hybridization (FISH; three tumors), RNA sequencing, reverse transcription (RT) PCR, and Sanger sequencing analyses (two tumors). All 7 tumors had karyotypic aberrations which included rearrangements of chromosome bands 8q11-13 (the criterion for selection into this study). FISH analyses with a PLAG1 break apart probe showed abnormal hybridization signals in both interphase nuclei and on metaphase spreads indicating PLAG1 rearrangement. RNA sequencing detected fusion between exon 1 of heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1) and exon 2 or 3 of PLAG1 in a lipoma and fusion between exon 2 of syndecan binding protein (SDCBP) and exon 2 or 3 of PLAG1 in a spindle cell lipoma. The HNRNPA2B1::PLAG1 and SDCBP::PLAG1 fusion transcripts were confirmed using RT-PCR/Sanger sequencing analyses. As 8q11-13 aberrations/PLAG1-rearrangements/PLAG1-chimeras may evidently be a defining pathogenetic feature of lipogenic neoplasms of several histological types and not just lipoblastomas, we suggest that the term "8q11-13/PLAG1-rearranged lipomatous tumors" be generally adopted for this tumor subset.

Advances in intravital imaging of liver immunity using optical microscopy and labeling methods

AbstractThe use of optical microscopy and labeling methods in intravital imaging allows for direct tracking of cell behavior and dynamic changes at the molecular level in the physiological or pathological microenvironment of living animals, revealing the spatiotemporal information of individual cells in the immune response. The liver is an immunological organ that contains unique innate and adaptive immune cells, including Kupffer cells (KCs) and different types of T cells, and is involved in coordinating multiple immune responses in the body. Using intravital imaging to visualize the movement behaviors and functions of immune cells during the reaction processes of the liver under physiological and pathological conditions has shed new light on the understanding of liver immunity, which is of great significance for the diagnosis and treatment of liver diseases. This review introduces various window models and labeling methods for the liver in intravital optical imaging and describes how it provides movement behavior and functional information about different types of immune cells, such as KCs and T cells, in the liver. Additionally, we highlight recent advances in intravital optical imaging of liver diseases, such as nonalcoholic fatty liver disease, infections, and tumors. This review aims to be a useful resource for comprehending the developments and achievements in intravital imaging of the liver and uncovering spatiotemporal information of immune response in a living microenvironment.

Epipericardial fat necrosis: a case report of an underdiagnosed disease.

Epipericardial fat necrosis: a case report of an underdiagnosed disease.

AI-Based Automated Lipomatous Tumor Segmentation in MR Images: Ensemble Solution to Heterogeneous Data

Deep learning (DL) has been proposed to automate image segmentation and provide accuracy, consistency, and efficiency. Accurate segmentation of lipomatous tumors (LTs) is critical for correct tumor radiomics analysis and localization. The major challenge of this task is data heterogeneity, including tumor morphological characteristics and multicenter scanning protocols. To mitigate the issue, we aimed to develop a DL-based Super Learner (SL) ensemble framework with different data correction and normalization methods. Pathologically proven LTs on pre-operative T1-weighted/proton-density MR images of 185 patients were manually segmented. The LTs were categorized by tumor locations as distal upper limb (DUL), distal lower limb (DLL), proximal upper limb (PUL), proximal lower limb (PLL), or Trunk (T) and grouped by 80%/9%/11% for training, validation and testing. Six configurations of correction/normalization were applied to data for fivefold-cross-validation trainings, resulting in 30 base learners (BLs). A SL was obtained from the BLs by optimizing SL weights. The performance was evaluated by dice-similarity-coefficient (DSC), sensitivity, specificity, and Hausdorff distance (HD95). For predictions of the BLs, the average DSC, sensitivity, and specificity from the testing data were 0.72 pm 0.16, 0.73 pm 0.168, and 0.99 pm 0.012, respectively, while for SL predictions were 0.80 pm 0.184, 0.78 pm 0.193, and 1.00 pm 0.010. The average HD95 of the BLs were 11.5 (DUL), 23.2 (DLL), 25.9 (PUL), 32.1 (PLL), and 47.9 (T) mm, whereas of SL were 1.7, 8.4, 15.9, 2.2, and 36.6 mm, respectively. The proposed method could improve the segmentation accuracy and mitigate the performance instability and data heterogeneity aiding the differential diagnosis of LTs in real clinical situations.

Case Report: Resection of Giant Mediastinal Liposarcoma Using the Partial Sternotomy Incision

Primary mediastinal liposarcomas are rare. There are four types of liposarcoma: well differentiated/atypical lipomatous tumor, dedifferentiated, myxoid, pleomorphic. In this study we report a rare case of a mediastinal well-differentiated liposarcoma that was successfully surgically removed. Because of the noninvasive growth pattern of most liposarcomas, patients often present with few symptoms, which was the case in our patient presenting only with dry cough. Normally these tumors are diagnosed by radiologic imaging. Common symptoms include cough, dyspnea, wheezing, chest pain, and weight loss. There are different histologic variants of liposarcoma, the most frequent one is well-differentiated liposarcoma. In our case we couldn’t confirm the histology with fine needle aspiration but with the frozen section we confirmed the diagnosis of well-differentiated liposarcoma. An optimal approach is very important to remove mediastinal liposarcoma because of the diversity of size and location of lesions.

Oncology

The February 2023 Oncology Roundup360 looks at: Is the number of national database research studies in musculoskeletal sarcoma increasing, and are these studies reliable?; Re-excision after unplanned excision of soft-tissue sarcoma is associated with high morbidity; Adjuvant radiation in atypical lipomatous tumours; The oncological outcomes of isolated limb perfusion and neoadjuvant radiotherapy in soft-tissue sarcoma patients - a nationwide multicentre study; Can low-grade chondrosarcoma be treated with intralesional curettage and cryotherapy?; Efficacy and safety of carbon ion radiotherapy for bone sarcomas: a systematic review and meta-analysis; Doxorubicin-polymeric meshes prevent local recurrence after sarcoma resection while avoiding cardiotoxicity; How important are skip lesions in Ewing’s sarcoma?; Improving outcomes for amputees: the health-related quality of life and cost utility analysis of osseointegration prosthetics in transfemoral amputees.

The Usefulness of Short-Interval Sequential FDG PET/CT Studies in Defining the Benignity of Hypermetabolic Lipomatous Tumor.

We present an interesting case of incidentally detected lipomatous tumor in an oncological patient that could result in a false-positive interpretation by exhibiting intense FDG activity similar to that of a malignant neoplasm. Careful evaluation of FDG uptake changes on sequential short-interval PET/CT studies was helpful in defining the benign nature of the tumor as the hypermetabolism was gradually disappearing obviating the need for a major surgery.

Silver In Situ Hybridization for the Rapid Assessment of MDM2 Amplification in Soft Tissue and Bone Tumors. Validation Based on an Audit of 192 Consecutive Cases Evaluated by Silver In Situ Hybridization and Fluorescence In Situ Hybridization.

The discovery of almost invariable mouse double minute 2 (MDM2) amplification among atypical lipomatous tumors (ALT)/well-differentiated liposarcoma and dedifferentiated liposarcoma is incorporated into the contemporary diagnostic workup of fatty lesions. MDM2 amplifications are also found frequently in intimal sarcomas and in low-grade osteogenic sarcoma. At present, fluorescence in situ hybridization (FISH) is the reference test for MDM2 assessment. We are interested in evaluating silver in situ hybridization (SISH) for this purpose. Between October 2016 and May 2020, in 192 consecutive cases requiring MDM2 FISH, SISH was also performed concurrently, including 77 (40.1%) core biopsies and 115 (58.9%) surgical specimens. The mean patient age was 61.0 years. SISH results were available overnight or within 48 hours if repeat testing was required. FISH results were available within 2 to 5 weeks. The cost of SISH was one third of FISH. FISH demonstrated MDM2 amplification in 44 cases (23.6%), was negative in 144 cases (74.4%) and nondiagnostic in 4 decalcified cases (2.0%). SISH showed MDM2 amplification in 33 cases (17.2%), no amplification in 119 cases (62.0%), and indeterminate results because of poor signal in 40 (20.8%) cases. All 33 (100%) SISH-amplified tumors and 113 of 119 (95.0%) nonamplified results were confirmed by FISH. There were no clear differences in the performance of SISH on NCB versus surgical specimens. The overall performance indices of SISH are sensitivity 75%, specificity 78.5%, positive predictive value 100%, and negative predictive value 95.8%. FISH is not required when SISH is clearly amplified. This is clinically useful and improves efficiency. Nonamplified SISH results provide early indications of the likely FISH findings, but there is a 4.2% chance of FISH being positive. At present, the main drawback of SISH is the high rate of nondiagnostic tests. Optimization of SISH signal detection to reduce the proportion of indeterminate results is our current focus.

Hibernoma-A rare tumor on rare site

Hibernoma is a rare benign tumor that originates from brown fat. Hibernoma is thought to arise from areas containing residual brown fat like- the interscapular area, axilla, neck, chest, abdominal cavity, and retroperitoneum. The incidence of this rare tumor has very rarely been reported to occur over the forehead. Being a benign tumor, no association of malignant transformation or metastasis has been reported. A 23-year-old male presented with a complaint of a painless non-progressive swelling over the forehead for the past 6 months. On examination, the swelling was 2x2 cm, soft, mobile, non-tender, and non-pulsatile with no skin changes. FNAC did which shows sheets and clusters of adipocytes with abundant foamy cytoplasm and reported as “Hibernoma”. The patient has been asked to follow up and for the last 1 year, the tumor is still non-progressive with no pressure symptoms and hence has not undergone surgery. Hibernoma is a rare benign tumor of brown fat tissue which constitutes only 1.6% of benign lipomatous tumors but their actual prevalence is still unknown. This tumor very rarely may occur in the forehead area although incidence over the forehead has rarely been reported. Since this tumor is slow growing, painless non-progressive; it mostly presents as an asymptomatic tumor. It has to be included in the differential diagnosis of adipocyte-containing tumors to prevent false treatment.

Differences in MRI findings of superficial spindle cell lipoma and atypical lipomatous tumor/well-differentiated liposarcoma.

This study aimed to evaluate the efficacy of using MRI findings to differentiate superficial spindle cell lipomas (SCLs) from atypical lipomatous tumor/well-differentiated liposarcomas (ALT/WDLs). This study included 12 patients with histopathologically proven superficial SCLs and 11 with ALT/WDLs. MRI findings for both pathologies were retrospectively reviewed and compared between the two pathologies. The neck, upper back, and shoulder regions were more frequent locations of SCLs than of ALT/WDLs (100% vs 55%, p < 0.05), whereas no significant differences were observed in age and sex. The median maximum diameter of the lesion was smaller in SCLs than in ALT/WDLs (44 mm [interquartile range (IQR): 35-63] vs 102 mm [IQR: 86-119], p < 0.05). On T 1 weighted images, non-fatty area was more frequently observed in SCLs than in ALT/WDLs (73% vs 25%, p < 0.05), and the median rate of non-fatty area was larger in SCLs than in ALT/WDLs (7.5% [IQR: 1.0-53] vs 0% [IQR: 0-0.2], p < 0.05). On fat-suppressed T 2 weighted images, a solid hyperintense area was more frequently observed in SCLs than in ALT/WDLs (83% vs 27%, p < 0.05). The maximum diameter, non-fatty area on T 1 weighted images, and solid hyperintense area on fat-suppressed T 2 weighted images were useful imaging features for differentiating superficial SCLs from ALT/WDLs. In superficial lipomatous tumors, small tumor size and non-fatty solid area were valuable findings for diagnosing SCLs.

Robustness of Radiomic Features: Two-Dimensional versus Three-Dimensional MRI-Based Feature Reproducibility in Lipomatous Soft-Tissue Tumors.

This retrospective study aimed to compare the intra- and inter-observer manual-segmentation variability in the feature reproducibility between two-dimensional (2D) and three-dimensional (3D) magnetic-resonance imaging (MRI)-based radiomic features. The study included patients with lipomatous soft-tissue tumors that were diagnosed with histopathology and underwent MRI scans. Tumor segmentation based on the 2D and 3D MRI images was performed by two observers to assess the intra- and inter-observer variability. In both the 2D and the 3D segmentations, the radiomic features were extracted from the normalized images. Regarding the stability of the features, the intraclass correlation coefficient (ICC) was used to evaluate the intra- and inter-observer segmentation variability. Features with ICC > 0.75 were considered reproducible. The degree of feature robustness was classified as low, moderate, or high. Additionally, we compared the efficacy of 2D and 3D contour-focused segmentation in terms of the effects of the stable feature rate, sensitivity, specificity, and diagnostic accuracy of machine learning on the reproducible features. In total, 93 and 107 features were extracted from the 2D and 3D images, respectively. Only 35 features from the 2D images and 63 features from the 3D images were reproducible. The stable feature rate for the 3D segmentation was more significant than for the 2D segmentation (58.9% vs. 37.6%, p = 0.002). The majority of the features for the 3D segmentation had moderate-to-high robustness, while 40.9% of the features for the 2D segmentation had low robustness. The diagnostic accuracy of the machine-learning model for the 2D segmentation was close to that for the 3D segmentation (88% vs. 90%). In both the 2D and the 3D segmentation, the specificity values were equal to 100%. However, the sensitivity for the 2D segmentation was lower than for the 3D segmentation (75% vs. 83%). For the 2D + 3D radiomic features, the model achieved a diagnostic accuracy of 87% (sensitivity, 100%, and specificity, 80%). Both 2D and 3D MRI-based radiomic features of lipomatous soft-tissue tumors are reproducible. With a higher stable feature rate, 3D contour-focused segmentation should be selected for the feature-extraction process.

FISH Diagnostic Assessment of MDM2 Amplification in Liposarcoma: Potential Pitfalls and Troubleshooting Recommendations.

MDM2 amplification represents the leading oncogenic pathway and diagnostic hallmark of liposarcoma, whose assessment is based on Fluorescence In Situ Hybridization (FISH) analysis. Despite its diagnostic relevance, no univocal interpretation criteria regarding FISH assessments of MDM2 amplification have been established so far, leading to several different approaches and potential diagnostic misinterpretations. This study aims to address the most common issues and proposes troubleshooting guidelines for MDM2 amplification assessments by FISH. We retrospectively retrieved 51 liposarcomas, 25 Lipomas, 5 Spindle Cell Lipoma/Pleomorphic Lipomas, and 2 Atypical Spindle Cell Lipomatous Tumors and the corresponding MDM2 FISH analysis. We observed MDM2 amplification in liposarcomas cases only (43 out of 51 cases) and identified three MDM2-amplified patterns (scattered (50% of cases), clustered (14% of cases), and mixed (36% of cases)) and two nonamplified patterns (low number of signals (82% of cases) and polysomic (18% of cases)). Based on these data and published evidence in the literature, we propose a set of criteria to guide MDM2 amplification analysis in liposarcoma. Kindled by the compelling importance of MDM2 assessments to improve diagnostic and therapeutic liposarcoma management, these suggestions could represent the first step to develop a univocal interpretation model and consensus guidelines.

Giemsa staining proved useful for fine-needle aspiration cytology of an atypical lipomatous tumor arising in the subcutaneous tissue of the left upper neck

Giemsa staining proved useful for fine-needle aspiration cytology of an atypical lipomatous tumor arising in the subcutaneous tissue of the left upper neck

Intraoral lipoma with degenerative changes mimicking atypical lipomatous tumor: an immunohistochemical study

Lipomas are mesenchymal neoplasms relatively uncommon in the oral cavity. Lipomas can exhibit histopathological features mimicking atypical lipomatous tumors (ALT) or dysplastic lipoma (DL) in the presence of degenerative changes. Relevantly, immunohistochemistry assists in the correct diagnosis. Herein, we present the case of a 54-year-old male with a sessile nodule located on the dorsum of the tongue. The histopathological analysis showed a diffuse, non-circumscribed adipocytic proliferation constituted by cells of variable size containing cytoplasmic vacuoles and displaced nuclei, some resembling lipoblasts supported by fibrous connective tissue stroma. By immunohistochemistry, tumor cells were positive for vimentin, S100, FASN, CD10, and p16. Rb expression was intact. Moreover, CD34, p53, MDM2, and CDK4 were negative. After 2-year of follow-up, no alteration or recurrence was observed. In conclusion, MDM2, CDK4, p53, and Rb immunomarkers can be used reliably to differentiate benign lipoma with degenerative changes from ALT and DL.

Well-Differentiated Liposarcoma as a Case: The Competence of Surgical Treatment was Questioned

Sarcomas are malignant tumors arising from skeletal and non-skeletal connective tissue, as well as the peripheral nervous system. Sarcoma is detected in the majority of patients who have a primary retroperitoneal, extra-visceral, unifocal soft tissue mass. Liposarcoma and leiomyosarcoma are the most prevalent histologic types of retroperitoneal sarcoma in adults. Most retroperitoneal liposarcomas are known as low to mild grade tumors. Well differentiated (low grade) liposarcomas are the most prevalent kind and have no potential to metastasize. Atypical lipomatous tumors are defined as those that develop on the body wall, trunk, or extremity. However, the same tumors are called well-differentiated liposarcomas due to their tendency for local recurrence and located in the retroperitoneum, mediastinum, and spermatic cord. In our case, we aimed to present a case that occupies most of the intra-abdominal volume, has associated gastrointestinal system complaints, and eventually was diagnosed as well-differentiated liposarcoma following surgical treatment.

Adipose and lipoma stem cells: A donor-matched comparison.

Lipomas are slow growing benign fat tumors that develop in soft tissues of the mesoderm. Thus, the specific (dys-)function of mesenchymal stem cells (MSCs) has been suggested in the development of lipomas, but details of the tumor pathogenesis remain unclear. Existing studies comparing stem cells from native adipose (adipose stem cells [ASCs]) and lipomatous tissues (LSCs) have reported contradicting findings. However, harvesting ASCs and LSCs from different individuals might have influenced proper comparison. Therefore, we aimed to characterize donor-matched ASCs and LSCs to investigate metabolic activity, proliferation, capability for tri-linear differentiation (chondrogenesis, adipogenesis, osteogenesis), and the secretome of mature adipocytes and lipomacytes. Both stem cell types did not differ in metabolic activity, but ASCs demonstrated stronger proliferation than LSCs. While there was no difference in proteoglycan accumulation during chondrogenic differentiation, adipogenesis was higher in ASCs, with more lipid vacuole formation. Conversely, LSCs showed increased osteogenesis by higher calcium deposition. Lipomacytes showed stronger secretory activity and released higher levels of certain adipokines. Our findings indicated that LSCs possessed important characteristics of MSCs, including ASCs. However, LSCs' low proliferation and adipogenic differentiation behavior did not appear to account for enhanced tissue proliferation, but the secretome of lipomacytes could contribute to lipomatous neoplasm.

Performance of Sonoelastography for predicting malignancy in soft tissue

BackgroundSeparating benign from malignant soft-tissue masses often requires a biopsy. The objective of this study was to assess whether shear-wave elastography (SWE) helped to separate benign from malignant soft-tissue masses.MethodsIn 2015–2016, we prospectively included patients with soft-tissue masses deemed by our multidisciplinary sarcoma board to require a diagnostic biopsy. All patients underwent ultrasonography (US) followed by SWE to measure elasticity. We compared benign and malignant tumors, overall and after separating tumors with vs. without a fatty component. The biopsy findings, and surgical-specimen histology when available, served as the reference standard.ResultsWe included 136 patients, 99 with non-fatty and 37 with fatty soft-tissue masses. Mean elasticity and tumor-to-fat elasticity ratio (T/F) values were significantly lower for the benign than the malignant soft-tissue masses in the overall cohort (30.9 vs. 50.0 kilopascals (kPa), P = 0.03; and 2.55 vs. 4.30, P = 0.046) and in the non-fatty subgroup (37.8 ± 31.9 vs. 58.9 ± 39.1 kPa, P = 0.049 and 2.89 ± 5.25 vs. 5.07 ± 5.41, P = 0.046). Data for fatty tumors were non relevant due to lack of conclusive results. By receiver operating characteristics curve analysis, a T/F cutoff of 3.5 had 46% sensitivity and 84% specificity for separating benign and malignant soft-tissue masses.ConclusionsSWE had good specificity and poor sensitivity for separating benign from malignant soft-tissue masses.

Abstract #1322506: Lipomatous Tumors of Adrenal Gland: A Case Series of 5 Patients and Review of the Literature

Lipomatous tumors of the adrenal glands are a diverse group of tumors characterized by the composition of adipose tissue. This group of tumors include myelolipomas, angiomyolipomas (AMLs), lipomas, and teratomas. They are usually benign, nonfunctioning tumors, and they account for 5% of all primary adrenal tumors. This study aimed to elucidate the management of the initial size of the adrenal mass and symptoms of presentation. We provide a succinct literature review regarding AMLs of the adrenal glands.

EVALUATION OF THE USEFULNESS OF SHEAR WAVE ELASTOGRAPHY IN THE DIAGNOSTIC PROCESS FOR NONCANCEROUS SOFT TISSUE MASSES

Current study was carried out to assess efficacy of SWE as an adjunct to sonography in investigating superficial benign lesions. The retrospective study was conducted in Radiology department of Nishtar Medical Hospital from July 2021 to July 2022. The study included 45 patients with 49 lesions. Doppler and grayscale ultrasound and SWE was performed. Conventional ultrasonic features like depth (mm), size (mm), margin (ill defined or well defined), vascularity (present or absent) and echogenicity (isoechoic, anechoic, hyperechoic or hypoechoic) were investigated. Median shear modulus and ultrasonic features were documented. Mean shear modulus for epidermoid, ganglion and lipomatous cyst was 23.6kPa, 5.9kPa and 9.1kPa respectively. Difference between lipomatous tumors, ganglion cysts and epidermoid cysts were significant (P=0.018). Median shear modulus of epidermoid cyst was higher than ganglion cysts and lipomatous tumors. Shear wave elastography is valuable modality for diagnosis of superficial benign soft tissue masses through direct quantitative analysis.

MRI findings to differentiate musculoskeletal dedifferentiated liposarcoma from atypical lipomatous tumor.

This study aimed to assess the efficacy of using MRI findings for differentiating musculoskeletal dedifferentiated liposarcoma (DDLP) from atypical lipomatous tumor (ALT). This study included 22 patients with histopathologically proven DDLP and 35 with ALT in the musculoskeletal areas. All DDLPs were immunohistochemically positive for MDM2. MRI findings for both pathologies were retrospectively reviewed and compared. The maximum lesion diameter was significantly lower in DDLPs than in ALTs (p < 0.01). Ill-defined margin, peritumoral edema, and tail sign were more frequently observed in DDLPs than in ALTs (p < 0.01, respectively). The fatty component was less frequently observed in DDLPs than in ALTs (27 vs. 100%; p < 0.01), whereas the non-fatty component was more frequently observed in DDLPs than in ALTs (100 vs. 11%; p < 0.01). The occupation rate by non-fatty components was significantly higher in DDLPs than in ALTs (p < 0.01). No significant differences were observed in imaging findings associated with fatty component; however, necrosis within the non-fatty component on the contrast-enhanced image was more frequently observed in DDLPs than in ALTs (72 vs. 0%, p < 0.05). DDLPs always had a non-fatty component, whereas ALTs always had fatty component. Ill-defined margin, peritumoral edema, tail sign, and necrosis within non-fatty components were useful MRI features for differentiating musculoskeletal DDLP from ALT.