Presentation
Swelling and pain in the right thigh.
Patient Data
The right medial compartment of the thigh shows a relatively defined oval fat signal intensity mass with thick enhancing septations and a soft tissue nodule. Tortuous and dilated vessels are seen in the posterior aspect of the mass. The mass is medially displacing and splaying the adductor muscles. No evidence of invasion is seen in the adjacent structures.
Histopathology and immunohistochemistry confirmed the diagnosis of well-differentiated liposarcoma.
Case Discussion
Liposarcoma (LPS) is a malignant mesenchymal neoplasm accounting for about 20–25% of adult soft-tissue sarcomas, frequently occurring in the extremities and in the retroperitoneum, with peak age of onset in the fifth to seventh decades 1,3.
The diagnosis is suggested by intratumoral adipose tissue on CT or MRI, but in some subtypes, macroscopic fat cannot be seen on imaging. LPS can be divided into three major groups. Atypical lipomatous tumors (ALT), well-differentiated LPS, and dedifferentiated LPS are all included in the first category. Myxoid LPS and round-cell LPS are included in the second category. Pleomorphic LPS is the main component of the third type. The first category, which makes up around 50% of all cases of LPS, is the most prevalent subtype 1.
Well-differentiated liposarcomas typically demonstrate a predominantly adipose mass containing nonlipomatous components, which are seen as thick septa (> 2 mm), nodular soft-tissue elements, or soft-tissue masses < 1 cm. The more differentiated the tumor, the more its imaging appearance can approach that of adipose tissue 1,2.
The myxoid subtype has a relatively characteristic appearance, with low signal intensity on T1-weighted images and markedly high signal intensity on T2. Pleomorphic liposarcoma subtypes may be indistinguishable from those of other aggressive soft-tissue sarcomas on imaging 1,2.
Dedifferentiated liposarcoma, which makes up around 5% of all cases of the disease, is the least common variety and mimics well-differentiated liposarcomas in its radiologic appearance as a nonlipomatous component inside a mostly adipose mass. The mass becomes even more suggestive of dedifferentiation if it has a focal soft-tissue nodule that is larger than 1 cm. Both well-differentiated and dedifferentiated liposarcoma have been reported to exhibit calcification or metaplastic ossification 1,3.
In our case, a predominant lipomatous mass with an enhancing soft-tissue nodule and thick septa in the right thigh suggested the possibility of a well-differentiated liposarcoma, which was later confirmed on histopathological examination.
Unable to process the form. Check for errors and try again.