Giant lipoma of the thigh: A case report.
ABSTRACT A lipoma is a benign tumor which can occur in any part of the body; it is very frequent and can reach a considerable size. Differentiation between lipoma and liposarcoma of low grade malignancy represents an important diagnostic problem, and valuable help in the differential diagnosis is provided by ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), biopsy and/or modern immunohistochemistry. The authors report the case of a 50-year-old man who was referred to their department due to the presence of a large mass growing on the upper thigh of the right leg; over 7 years it had steadily increased in size causing pain and functional impotence. US of the soft tissues and CT scanning were performed. Densitometric values of the mass suggested adipose tissue, which was subsequently confirmed by biopsy.
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ABSTRACT: Lipomas are frequent benign soft tissue tumors. They are classified as superficial or deep. In the head, they are localized under the galea or epicraneal aponeurosis. Clinically they present as non symptomatic smooth tumors. To describe ultrasound (US) findings of subgaleal lipomas. Retrospective review of seven patients aged between 31 and 52 years (five males) with subgaleal lipomas. AH lipomas were localized in the forehead. At US, they appeared as solid masses; 43% were isoechoic and 47% hyperechoic compared to subcutaneous tissue. The average size was 13 mm. They had a semi spherical shape, with a flat base and a convex surface, a regular margin, no vascular vessels at Doppler ultrasound and were surrounded by the galea. In this series of patients, all masses had a similar US appearance that suggested the diagnosis of lipoma.Revista medica de Chile 04/2008; 136(3):334-7. · 0.36 Impact Factor
Article: Lipomatous tumors.[Show abstract] [Hide abstract]
ABSTRACT: Lipomatous tumors are a common group of mesenchymal lesions. Over the years the major changes in the classification of lipomatous tumors have included the addition of several new variants of lipoma, the use of the term atypical lipoma for well differentiated liposarcoma of the subcutaneous tissue, and recognition of the entity dedifferentiated liposarcoma. Lipomas, the most common lipomatous tumor, account for nearly one-half of all benign lesions. In their typical form they seldom present diagnostic problems for the pathologist. However, lipomas occurring in deep locations (e.g., intramuscular lipoma, perineural lipoma) or those having unusual features (e.g., chondroid lipoma, lipoma with hibernoma, cellular angiolipoma, spindle cell/pleomorphic lipoma) may be confused with liposarcoma. Recent cytogenetic studies have reaffirmed the separate nature of many of the variants of lipoma. Solitary lipomas commonly have rearrangements of chromosome 12, a finding not encountered in multiple lipomas or in spindle cell/ pleomorphic lipoma. Liposarcoma is the most common adult soft tissue sarcoma. It seldom arises from subcutaneous tissues or from preexisting lipomas, and is seldom found in children. The hallmark of liposarcoma is the immature fat cell or lipoblast. Diagnostic lipoblasts have an eccentric, hyperchromatic nucleus, which is indented or scalloped by the presence of one or more fat vacuoles. It is important that these cells occur in the appropriate histologic background because similar cells can be seen in a variety of nonlipomatous lesions (e.g., silicone reaction). Failure to apply strict criteria in identifying such cells and in noting the milieu in which they occur can lead to overdiagnosis of liposarcoma. Liposarcomas are divided into several subtypes: well differentiated, myxoid, round cell, pleomorphic, and dedifferentiated. Liposarcomas can be conceptualized as occurring in two broad groups, myxoid/round cell liposarcoma and well differentiated/dedifferentiated liposarcoma. Myxoid/round cell liposarcomas occur in middle-aged adults primarily as an extremity lesion. Tumors range from pure myxoid (low grade) to pure round cell (high-grade lesions) with some cases having transitional features. Behavior can be related to the amount of round cell areas. A consistent chromosome abnormality t(12;16) characterizes this spectrum of lesions. Well differentiated/dedifferentiated liposarcomas, in contrast, occur in late adult life as extremity or retroperitoneal lesions. They consist of mature fat interlaced with atypical hyperchromatic cells and rare lipoblasts. These lesions recur commonly, but they do not metastasize. Their behavior is strongly influenced by location, with retroperitoneal lesions having the worse prognosis. As a long-term complication of the disease, these lesions may progress histologically (dedifferentiate), a phenomenon that confers upon them metastatic potential. Dedifferentiation is largely a time-dependent phenomenon that occurs in sites in which there is a high likelihood for clinical persistence of disease (e.g., the retroperitoneum). Dedifferentiated liposarcomas occur in an age group similar to well differentiated liposarcoma, but are found far more commonly in the retroperitoneum. Most occur as de novo lesions, with only a small percentage occurring as a late complication of well differentiated liposarcoma, as described above. They consist of well differentiated areas associated with nonlipogenic sarcoma usually resembling high-grade malignant fibrous histiocytoma or fibrosarcoma. However, the range of histologic features occurring in the dedifferentiated areas is more varied than previously appreciated. Low-grade areas resembling fibromatosis or low-grade fibrosarcoma may be seen as the sole expression of dedifferentiation or may co-exist with high-grade sarcoma. (ABSTRACT TRUNCATED)Monographs in pathology 02/1996; 38:207-39.
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ABSTRACT: Giant lipomas of the thenar are rare tumours of the adipose tissue of the hand, with a benign prognosis. Apart from the cosmetic problems they may cause, their most frequent complications include a compromise in functionality and pressure upon the nerves, mainly on the radial nerve. The first step in their management is their differential diagnosis from well-differentiated liposarcomas (WDLPS), as they require a different therapeutic approach. This step is completed with the aid of MRIs, biopsies and modern immunohistochemical methods, which offer high specificity and sensitivity. Our paper presents a case of giant lipoma of the thenar, with a review of the relevant literature, focusing on the disease's molecular genetics, which is a very important field of research today.Hand 01/2009; 4(2):173-6.