Commentary: Case Report: a giant liposarcoma of the spermatic cord

Jiro Ichikawa^1*Tomonori Kawasaki²Masanori Wako¹Satoshi Ochiai³Tetsuhiro Hagino³Tetsuo Hagino³Kojiro Onohara⁴

• ¹Department of Orthopedic Surgery, University of Yamanashi, Yamanashi, Japan
• ²Saitama Ika Daigaku Kokusai Iryo Center, Hidaka, Japan
• ³Kofu Byoin, Kofu, Japan
• ⁴Yamanashi Daigaku Igakubu Daigakuin Sogo Kenkyubu Igakuiki Hoshasen Igaku Koza, Chuo, Japan

Liposarcomas comprise four subtypes, including well-differentiated, myxoid, pleomorphic, and dedifferentiated (1). They are most commonly located in the extremities and retroperitoneum, with well-differentiated liposarcomas (WDLPSs) being the most prevalent (1). We were very interested in the recent publication by Wang et al., "Case Report: A Giant Liposarcoma of the Spermatic Cord," and sincerely appreciate the authors reporting this valuable case (2). Our differential diagnoses are i) atypical lipomatous tumor/well-differentiated liposarcoma (ALT/WDLPS) and dedifferentiated liposarcoma (DDLPS) based on pathological findings, and ii) myxoid liposarcoma (MLS) based on accompanying magnetic resonance imaging (MRI). Herein, we present the histopathological and imaging characteristics of ALT/WDLPS, DDLPS, and MLS for further discussion. Regarding the MRI findings, T1-and T2-weighted images were unavailable, making it difficult to confirm that all suppressed areas in this case represented adipose tissue. These images should therefore be presented, if possible, for greater diagnostic clarity. Regarding the pathological findings, only low-magnification images were provided. As histological evaluation is crucial for differentiating the four tumor subtypes, high-magnification images should be included to clearly depict the morphological characteristics of the constituent cells. shown a correlation between high CDK4 expression and poor prognosis, suggesting that CDK4 may be useful not only for diagnosis but also as a prognostic factor (7).Differentiating ALT/WDLPS from DDLPS is critical because of significant differences in recurrence rates and overall survival (3). MLS is the second most common liposarcoma, frequently occurring in the proximal extremities (1). Although similar to ALT/WDLPS and DDLPS, MLS is cytogenetically distinct, characterized by the t(12;16)(q13:p11) translocation producing the FUS-DDIT3 fusion protein (8), with the EWSR1-DDIT3 fusion being a less-common variant (8).Histologically, MLS consists of round-to-oval mesenchymal tumor cells lacking adipocytic differentiation, co-existing with variable uni-or multi-vacuolated lipoblasts (1). The tumor contains a myxoid matrix with chicken-wire capillary networks (8). MLSs with ≥5% round-cell components are classified as high-grade and associated with poor prognosis (1,9). No specific IHC markers reliably diagnose MLS (8), so differentiation from other round-cell sarcomas requires FISH or polymerase chain reaction. Although FUS and EWSR1 may occur in other tumors, DDIT3 is unique to MLS (8). The 5-year survival rate of MLS is approximately 80%, whereas 20% of cases develop metastases, often extrapulmonary, particularly to bone and the retroperitoneum (a pattern distinct from other sarcomas) (9). Compared to other liposarcomas, MLS exhibits higher sensitivity to chemotherapy and radiotherapy, making this a notable therapeutic feature (9). The key clinicopathological distinguishing features among ALT/WDLPS, DDLPS, and MLS are summarized in Table 1. When considering prognosis and treatment, the discussion should focus on DDLPS and MLS. A key MRI characteristic of DDLPS is the presence of fat components resembling WDLPS (10). However, fat presence varies, and 73% of cases show no fat (11). Non-fat components often exhibit intermediate T2-weighted signals. In contrast, MLS is characterized by fat components and myxoid elements (10). In MLS, fat components are absent in over 75% of cases, with 30% possessing 0-50% fat and 63.9% showing no fat content (10). Regarding myxoid components, 17% of cases exceed 75% myxoid content, 30% possess 50-75%, and 53% possess less than 50% (10). A higher proportion of myxoid components is significantly associated with lower histological grades (10).Contrast enhancement is more pronounced in DDLPS than MLS (10). These findings make detailed differentiation using T2 fat suppression alone extremely challenging.Introducing T1, T2, and, if possible, contrast-enhanced T1-weighted images would aid differential diagnosis. Furthermore, given the existence of myxoid DDLPS, accurate subtype identification requires combined evaluation of imaging and pathological findings.