From the archives of the AFIP: Benign musculoskeletal lipomatous lesions
University of Maryland, Baltimore, Baltimore, Maryland, United States Radiographics
(Impact Factor: 2.6).
09/2004; 24(5):1433-66. DOI: 10.1148/rg.245045120
Benign lipomatous lesions involving soft tissue are common musculoskeletal masses that are classified into nine distinct diagnoses: lipoma, lipomatosis, lipomatosis of nerve, lipoblastoma or lipoblastomatosis, angiolipoma, myolipoma of soft tissue, chondroid lipoma, spindle cell lipoma and pleomorphic lipoma, and hibernoma. Soft-tissue lipoma accounts for almost 50% of all soft-tissue tumors. Radiologic evaluation is diagnostic in up to 71% of cases. These lesions are identical to subcutaneous fat on computed tomographic (CT) and magnetic resonance (MR) images and may contain thin septa. Lipomatosis represents a diffuse overgrowth of mature fat affecting either subcutaneous tissue, muscle or nerve, and imaging is needed to evaluate lesion extent. Lipoblastoma is a tumor of immature fat occurring in young children, and imaging features may reveal a mixture of fat and nonadipose tissue. Angiolipoma, myolipoma, and chondroid lipoma are rare lipomatous lesions that are infrequently imaged. Spindle cell and pleomorphic lipoma appear as a subcutaneous lipomatous mass in the posterior neck or shoulder, with frequent nonadipose components. Hibernoma appears as a lipomatous mass with serpentine vascular elements. Benign lipomatous lesions affecting bone, joint, or tendon sheath include intraosseous lipoma, parosteal lipoma, liposclerosing myxofibrous tumor, discrete lipoma of joint or tendon sheath, and lipoma arborescens. Intraosseous and parosteal lipoma have a pathognomonic CT or MR appearance, with fat in the marrow space or on the bone surface, respectively. Liposclerosing myxofibrous tumor is a rare intermixed histologic lesion commonly located in the medullary canal of the intertrochanteric femur. Benign lipomatous lesions may occur focally in a joint or tendon sheath or with diffuse villonodular proliferation in the synovium (lipoma arborescens) and are diagnosed based on location and identification of fat. Understanding the spectrum of appearances of the various benign musculoskeletal lipomatous lesions improves radiologic assessment and is vital for optimal patient management.
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- "Magnetic resonance imaging (MRI) is the method of choice when examining soft tissue tumors  . Some benign tumors, such as lipomas and hemangiomas, can be safely diagnosed using MRI without the need of a biopsy   . "
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To determine the incidence of intra-articular synovial sarcomas and investigate if any radiological variables can differentiate them from localized (unifocal) pigmented villonodular synovitis (PVNS) and if multivariate data analysis could be used as a complementary clinical tool.
Magnetic resonance images and radiographs of 7 cases of intra-articular synovial sarcomas and 14 cases of localized PVNS were blindedly reviewed. Variables analyzed were size, extra-articular growth, tumor border, blooming, calcification, contrast media enhancement, effusion, bowl of grapes sign, triple signal intensity sign, synovial low signal intensity, synovitis, age, and gender. Univariate and multivariate data analysis, the method of partial least squares-discriminant analysis (PLS-DA), were used. Register data on all synovial sarcomas were extracted for comparison.
The incidence of intra-articular synovial sarcomas was 3%. PLS-DA showed that age, effusion, size, and gender were the most important factors for discrimination between sarcomas and localized PVNS. No sarcomas were misclassified as PVNS with PLS-DA, while some PVNS were misclassified as sarcomas.
The most important variables in differentiating intra-articular sarcomas from localized PVNS were age, effusion, size, and gender. Multivariate data analysis can be helpful as additive information to avoid a biopsy, if the tumor is classified as most likely being PVNS.
Available from: PubMed Central
- "Lipoblastoma is commonly located in the subcutaneous or superficial soft tissue of the extremity and clinically may simulate lipoma [7, 10]. Lipoblastomas are frequently asymptomatic and painless, except when they impinge on surrounding structures, causing symptoms by their mass effect [3, 4]. "
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ABSTRACT: Lipoblastoma is a benign lesion of immature fat cells that is found almost exclusively in pediatric population. This tumor is a rare tumor that occurs in infancy and early childhood, accounting for less than 1% of all childhood neoplasm. It is more common in male than in female and often presents as an asymptomatic, rapidly enlarging, soft lobular mass on the extremity. Although benign, it gives great difficulty in its management, due to its extensions into different facial planes, especially in lipoblastomatosis. Thus, complete surgical excision is the treatment of choice.
Available from: Sofia Jayi
- "However, Ohguri et al. showed that septal enhancement in contrast-enhanced MRI allows the differentiation of liposarcoma ; they found moderate or marked septal enhancement in 25% and 75%, respectively, of well-differentiated liposarcomas . Therefore, soft lipomatous lesions with thin septa that are not enhanced on MRI could be diagnosed as lipoma [3,9]. "
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Vulvar lipoma is a rare tumor localization and only a few cases have been reported. The clinical characteristics of vulvar lipoma are well known. However, it is important to distinguish lipomas from liposarcomas. We report a case of vulvar lipoma and discuss its clinical features, including diagnostic aspects, with emphasis on histopathological evaluation of all excised lesions. We also report and discuss patient management and treatment outcomes.
We report the case of a 27-year-old Moroccan woman. Our patient presented with a painless and slow-growing right vulvar mass that had evolved over one year, which had suddenly become uncomfortable when walking. A physical examination revealed a single soft and pasty mass in her left labium majus, which could be mobilized under her skin towards her mons pubis. The largest dimension of the mass measured 6cm. Magnetic resonance imaging showed a homogenous hyperintense mass with a well-defined contour in her left labium majus; a fat-suppressed magnetic resonance image demonstrated a marked signal intensity decrease. The mass was completely removed surgically. A histological examination revealed a circumscribed benign tumor composed of mature adipocytes, confirming the diagnosis of vulvar lipoma.
Vulvar lipomas must be differentiated from liposarcomas, which demonstrate very similar clinical and imaging profiles. The final diagnosis should be based on histopathological evaluation. A precise diagnosis should allow for appropriate surgical treatment.
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