Nuclear morphological atypia in biopsy accurately reflects the prognosis of myxoid liposarcoma.

Currently, it is difficult to predict the prognosis of myxoid liposarcoma (MLS) in biopsy specimens. In this study, we determined whether nuclear morphology may be used to predict the prognosis of MLS in primary biopsy specimens. Two pathologists evaluated nuclear morphology using the modified WHO/ISUP and Fuhrman grades. Survival analyses were performed by grouping nuclear high- and low-grades. We examined 53 MLS cases, which included 29 (54.7%) male and 24 (45.3%) female patients with a median age of 46 years (interquartile range, 37 - 60). In total, 7 (13.2%) and 16 (30.2%) cases were assigned to the high nuclear grade group based on the modified WHO/ISUP and Fuhrman gradings, respectively. Survival analyses revealed a significantly worse disease-free survival in the high-grade group (hazard ratio (HR), 7.51; 95% confidence interval (CI), 2.67-21.1, p < 0.001 by the modified WHO/ISUP grading; HR, 4.45; 95% CI, 1.63-12.1, p = 0.001 by the modified Fuhrman grading). Moreover, the modified WHO/ISUP grade showed a significantly worse overall survival in the high-grade group (HR, 4.39; 95% CI, 1.04-18.6, p = 0.028), and the modified Fuhrman grade exhibited a similar, but not significant, trend. Our results indicate that nuclear morphology grading is a good predictor of patient prognosis at the time of biopsy in MLS. Even when cell density is sparse, treatment strategies should be carefully considered when individual tumor cells exhibit atypical nuclei.

DDIT3-amplified or low-polysomic pleomorphic sarcomas without MDM2 amplification: Clinicopathological review and immunohistochemical profile of nine cases.

Several high-grade pleomorphic sarcoma cases that cannot be classified into any existing established categories have been reported. These cases were provisionally classified into undifferentiated pleomorphic sarcoma (UPS). Some dedifferentiated liposarcoma (DDLS) cases may also have been classified into the UPS category due to the absence of MDM2 amplification or an atypical lipomatous tumor/well-differentiated liposarcoma component. We retrieved and reviewed 77 high-grade pleomorphic sarcoma cases, initially diagnosed as UPS in 66 cases and DDLS in 11 cases. Fluorescence in situ hybridization (FISH) analyses of DDIT3 and MDM2 were performed for available cases. Of the cases successfully subjected to DDIT3 FISH (n = 56), nine (7 UPS and 2 DDLS) showed DDIT3 amplification but no MDM2 amplification. Two UPS cases showed both telomeric (5') and centromeric (3') amplification of DDIT3 or low polysomy of chromosome 12, whereas 5 UPS and 2 DDLS cases showed 5'-predominant DDIT3 amplification. Histopathologically, all cases showed UPS-like proliferation of atypical pleomorphic tumor cells. Immunohistochemically, only one case showed focal nuclear positivity for DDIT3, supporting the previous finding that DDIT3 expression was not correlated with DDIT3 amplification. All three cases with focal MDM2 expression involved 5'-predominant amplification, two of which showed DDLS-like histological features. The majority of cases (7/9) showed decreased expression in p53 staining, suggesting that DDIT3 amplification regulates the expression of TP53 like MDM2. From a clinicopathological perspective, we hypothesize that DDIT3-amplified sarcoma, especially with 5'-predominant amplification, can be reclassified out of the UPS category.