Department of Pathology and Biological Responses, Nagoya University Graduate School of Medicine, Nagoya, Japan.
Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Histopathology. 2018 Apr;72(5):729-738. doi: 10.1111/his.13421. Epub 2017 Dec 22.
Ossification is found occasionally in dedifferentiated liposarcoma (DDLPS). The aims of this study were to elucidate whether the formed bone tissue is usually produced by tumour cells or by reactive non-neoplastic cells, and to reveal the clinicopathological characteristics of DDLPS with ossification.
We examined 36 cases of ossified DDLPS by comparing them to 31 cases of non-ossified DDLPS. MDM2 amplification was confirmed in osteocytes and/or osteoblastic cells in all but one ossified DDLPS cases (27 of 28) using fluorescence in-situ hybridisation, although the morphological impression of ossification appeared to be mainly metaplastic (27 of 36) or high-grade osteosarcoma-like (six of 36). The bone tissue was often formed predominantly at the periphery of the DDLPS area near the well-differentiated liposarcoma component (18 of 36), and an organised structure such as bone marrow-like differentiation was not uncommon (12 of 36). According to a modified French Fédération Nationale des Centers de Lutte Contre le Cancer (FNCLCC) grading system, ossified DDLPS tended to be lower grade than non-ossified DDLPS (mean grade: 1.88 and 2.15, respectively). Ossification in DDLPS was associated significantly with shorter local recurrence-free survival by multivariate analysis (P = 0.02347), but metaplastic-appearing ossification tended to be associated with longer overall survival (P = 0.1400).
The bone tissue formed in DDLPS was mainly neoplastic regardless of its morphology and maturity, which highlighted the osteogenic differentiation of the tumour cells. DDLPS patients with osteogenic differentiation tended to suffer from earlier local recurrences, which did not necessarily lead to poor life outcomes.
去分化脂肪肉瘤（DDLPS）偶尔会发生骨化。本研究的目的是阐明形成的骨组织通常是由肿瘤细胞还是反应性非肿瘤细胞产生的，并揭示伴有骨化的 DDLPS 的临床病理特征。
我们通过比较 31 例非骨化 DDLPS 来检查 36 例骨化 DDLPS。除了 1 例（28 例中的 27 例）外，所有骨化 DDLPS 病例均通过荧光原位杂交证实了 MDM2 扩增，尽管骨化的形态学印象主要是化生（36 例中的 27 例）或高级别成骨肉瘤样（36 例中的 6 例）。骨组织通常主要在靠近分化良好的脂肪肉瘤成分的 DDLPS 区域周围形成（36 例中的 18 例），并且常见有组织样结构如骨髓样分化（36 例中的 12 例）。根据改良的法国国家抗癌中心联合会（FNCLCC）分级系统，骨化 DDLPS 的分级低于非骨化 DDLPS（平均分级：1.88 和 2.15）。多因素分析显示，DDLPS 中的骨化与较短的局部无复发生存时间显著相关（P=0.02347），但化生样骨化与较长的总生存期相关（P=0.1400）。
无论其形态和成熟度如何，DDLPS 中形成的骨组织主要是肿瘤性的，这突出了肿瘤细胞的成骨分化。具有成骨分化的 DDLPS 患者更容易发生早期局部复发，但不一定导致不良的生存结局。
