Infiltrating angiolipoma with phlebolith formation

Sonographic Differentiation Between Angiolipomas and Superficial Lipomas

OBJECTIVES

The purpose of this study was to compare the sonographic findings of angio lipomas with those of superficial lipomas.

METHODS

Preoperative sonograms of 26 angiolipomas from 18 patients and 47 superficial lipomas from 43 patients that were confirmed by biopsy were reviewed retrospectively. The echo texture, echogenicity, internal echogenic stranding, vascularity, visualization of lateral and superficial-deep tumor capsules, shape, and tumor length, width, and length-to-width ratio were evaluated and compared between angiolipomas and superficial lipomas.

RESULTS

Angiolipomas frequently appeared as heterogeneous (19 of 26 [73.1%]), hyperechoic (23 of 26 [88.5%]), and ovoid (17 of 26 [65.4%]) masses with lesser visualized lateral tumor capsules (6 of 26 [23.1%]), whereas superficial lipomas appeared as homogeneous (36 of 47 [76.6%]), isoechoic (35 of 47 [74.5%]), and spindle-shaped (23 of 47 [48.9%]) masses with well-visualized lateral capsules (33 of 47 [70.2%]), and the differences were statistically significant (P < .001). Vascularity was seen in 4 angiolipomas (16.7%) and in no superficial lipomas (0%). The mean length and width ± SD of angiolipomas (2.2 ± 1.02 and 0.6 ± 0.27 cm, respectively) were smaller than those of superficial lipomas (4.2 ± 1.52 and 1.1 ± 0.51 cm), with statistical significance (P< .001). The other sonographic findings did not reveal statistically significant differences between the tumor types.

CONCLUSIONS

Sonography might help differentiate angiolipomas from superficial lipomas.

Benign fatty tumors: classification, clinical course, imaging appearance, and treatment

Lipoma is the most common soft-tissue tumor, with a wide spectrum of clinical presentations and imaging appearances. Several subtypes are described, ranging from lesions entirely composed of mature adipose tissue to tumors intimately associated with nonadipose tissue, to those composed of brown fat. The imaging appearance of these fatty masses is frequently sufficiently characteristic to allow a specific diagnosis. However, in other cases, although a specific diagnosis is not achievable, a meaningful limited differential diagnosis can be established. The purpose of this manuscript is to review the spectrum of benign fatty tumors highlighting the current classification system, clinical presentation and behavior, spectrum of imaging appearances, and treatment. The imaging review emphasizes computed tomography (CT) scanning and magnetic resonance (MR) imaging, differentiating radiologic features.

From the archives of the AFIP: benign musculoskeletal lipomatous lesions

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.