Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.
J Ayub Med Coll Abbottabad. 2021 Oct-Dec;33(4):563-567.
The 2013 World Health Organization (WHO) classification of soft tissue and bone tumours recognizes benign entities such as lipoma and four major liposarcoma subtypes: atypical lipomatous tumour/well differentiated liposarcomas (ALT/WDL), dedifferentiated liposarcomas (DDL), myxoid liposarcoma and pleomorphic liposarcoma. This classification of atypical and malignant adipocytic tumours has evolved significantly over the past few decades owing to contributions from cytogenetics, molecular genetics and Immunohistochemical correlates. Most ALT/WDLs can be diagnosed on histology; however, some of the biopsies may be underdiagnosed due to focal atypia or limited nature of tissue for the biopsy. Fluorescence in situ hybridization (FISH) for MDM2 (located at 12q14-15) gene amplification has emerged as gold standard for diagnosis in cases with limiting histological factors.
We studied MDM2 amplification by FISH in 55 such problematic adipocytic tumours with overlapping morphological features and a retrospective analysis was made against their corresponding histological features.
MDM2 amplification correctly identified 11 of 17 ALT/WDLs (64.71% concordance) and 8 of 10 Lipomas (80% concordance). We were able to differentiate liposarcomas from other high grade sarcomatous lesions and sub-classified these lesions into pleomorphic and dedifferentiated types.
FISH for MDM2 amplification should be used as a gold standard in adjunction with morphology and immunohistochemistry for problematic adipocytic neoplasms.
2013 年世界卫生组织（WHO）软组织和骨肿瘤分类承认良性实体，如脂肪瘤和四种主要脂肪肉瘤亚型：非典型性脂肪肉瘤/高分化脂肪肉瘤（ALT/WDL）、去分化脂肪肉瘤（DDL）、黏液样脂肪肉瘤和多形性脂肪肉瘤。由于细胞遗传学、分子遗传学和免疫组织化学相关性的贡献，这种非典型和恶性脂肪细胞肿瘤的分类在过去几十年中发生了重大变化。大多数 ALT/WDL 可以通过组织病理学诊断；然而，由于活检的局灶性异型性或组织有限，一些活检可能会被误诊。荧光原位杂交（FISH）检测 MDM2（位于 12q14-15）基因扩增已成为具有限制组织学因素病例的诊断金标准。
我们研究了 55 例具有重叠形态特征的此类有问题的脂肪性肿瘤中 MDM2 扩增情况，并对其相应的组织学特征进行了回顾性分析。
MDM2 扩增正确识别了 17 例 ALT/WDL 中的 11 例（64.71%的一致性）和 10 例脂肪瘤中的 8 例（80%的一致性）。我们能够将脂肪肉瘤与其他高级别肉瘤性病变区分开来，并将这些病变细分为多形性和去分化类型。
对于有问题的脂肪性肿瘤，FISH 检测 MDM2 扩增应与形态学和免疫组织化学一起作为金标准使用。
