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

Abstract

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.

Intrathoracic lipoma of chest wall misdiagnosed as liposarcoma with malignant features based on radiological image and intraoperative findings

“…Lipomas are discrete, encapsulated, homogeneous fatty masses on CT and MRI. On the other hand, thickened or nodular septa (>2 mm), prominent foci of high T2 signal and prominent areas of enhancement on MRI have been reported to be features suspicious of liposarcoma [ 5 , 6 ]. In addition, tumor size >10 cm and fat content <75% have been reported as radiological features of liposarcoma [ 6 ].…”

“…On the other hand, thickened or nodular septa (>2 mm), prominent foci of high T2 signal and prominent areas of enhancement on MRI have been reported to be features suspicious of liposarcoma [ 5 , 6 ]. In addition, tumor size >10 cm and fat content <75% have been reported as radiological features of liposarcoma [ 6 ]. SUVmax of FDG-PET reported that lipomas measured 0.8 ± 0.2 and well-differentiated liposarcomas measured 2.3 ± 1.2 [ 7 ].…”

Upper extremity mass with lipomatous axillary involvement and multiple level encasement of the brachial plexus

“…ALT and WDLS, which are locally aggressive tumors, are often grouped together in the literature and referred to synonymously since they are identical morphologically, only differing by tumor location [12 , 13] . ALTs are in areas accessible for surgical resection such as the trunk and extremities, where tumors in regions that cannot be resected such as the retroperitoneum, are termed WDLS [12 , 13] . Both ALT and WDLS are considered low-grade malignancies as they are not known to cause distant metastases, as their aggressive liposarcoma counterpart [12] .…”

“…Both ALT and WDLS are considered low-grade malignancies as they are not known to cause distant metastases, as their aggressive liposarcoma counterpart [12] . However, surgical resection is still important to confirm pathology, to eliminate the potential for de-differentiation, although rare especially in the superficial locations, and to minimize persistent local advancement of disease [13] .…”

“…In other rare occasions, these deep-seated lipomas can be intermuscular, traversing fascial compartments and their associated components [2 , [4] , [5] , [6] , [7] . Patients may experience symptoms such as pressure, pain, or even sensory and motor deficits due to continued lipoma growth and compression of the surrounding neurovascular structures [1 , 2 , 7 , 13] . We describe such a case with an unusual presentation of an irregularly shaped, infiltrating lipoma of the axilla, upper arm, and multiple levels of brachial plexus involvement.…”