Abstract：
OBJECTIVE: Classification of renal neoplasms on small tissue biopsies is in increasing demand, and maintaining broad differential diagnostic considerations in this setting is necessary. When evaluating a renal or perirenal tumour biopsy with sarcomatoid morphology, together with sarcomatoid renal cell carcinoma and sarcomatoid urothelial carcinoma as top diagnostic considerations, it is vital to additionally consider the possibility of well-differentiated and de-differentiated liposarcoma.
RESULTS: This study reports a series of 30 biopsy samples from sites in or around the kidney collected from four institutions in which the correct diagnosis was either well-differentiated or de-differentiated liposarcoma. The majority (26 of 30, 87%) of lesions were accurately diagnosed on biopsy sampling, all of which incorporated testing for MDM2 by immunohistochemistry (IHC), fluorescence in-situ hybridisation (FISH) or a combination of the two as part of the diagnostic work-up. Tumour expression of MDM2 by IHC without confirmatory FISH analysis was sometimes (30%) sufficient to reach a diagnosis, but demonstration of MDM2 amplification by FISH was ascertained in the majority (57%) of biopsy samples. A diagnosis of de-differentiated liposarcoma was not definitively established until resection in four (13%) patients, as no MDM2 testing was performed on the corresponding pre-operative biopsies.
CONCLUSIONS: When a retroperitoneal tumour is not clinically suspected, histological consideration of a liposarcoma diagnosis may be overlooked. Implementation of ancillary immunohistochemical and cytogenetic testing can ultimately lead to a definitive diagnosis in this potentially misleading anatomical location.
RESULTS: This study reports a series of 30 biopsy samples from sites in or around the kidney collected from four institutions in which the correct diagnosis was either well-differentiated or de-differentiated liposarcoma. The majority (26 of 30, 87%) of lesions were accurately diagnosed on biopsy sampling, all of which incorporated testing for MDM2 by immunohistochemistry (IHC), fluorescence in-situ hybridisation (FISH) or a combination of the two as part of the diagnostic work-up. Tumour expression of MDM2 by IHC without confirmatory FISH analysis was sometimes (30%) sufficient to reach a diagnosis, but demonstration of MDM2 amplification by FISH was ascertained in the majority (57%) of biopsy samples. A diagnosis of de-differentiated liposarcoma was not definitively established until resection in four (13%) patients, as no MDM2 testing was performed on the corresponding pre-operative biopsies.
CONCLUSIONS: When a retroperitoneal tumour is not clinically suspected, histological consideration of a liposarcoma diagnosis may be overlooked. Implementation of ancillary immunohistochemical and cytogenetic testing can ultimately lead to a definitive diagnosis in this potentially misleading anatomical location.
摘要：
目的：对肾肿瘤小组织活检分类的需求不断增加，并且在此设置中保持广泛的鉴别诊断注意事项是必要的。当评估有肉瘤样形态的肾或肾周肿瘤活检时，连同肉瘤样肾细胞癌和肉瘤样尿路上皮癌作为首要诊断考虑因素，此外,还必须考虑高分化和去分化脂肪肉瘤的可能性.
结果：本研究报告了从四个机构收集的肾脏内部或周围部位的一系列30个活检样本，其中正确诊断为高分化或去分化脂肪肉瘤。大多数（30个中的26个，87％）病变在活检取样中被准确诊断，所有这些都包括通过免疫组织化学（IHC）检测MDM2，荧光原位杂交（FISH）或两者的组合作为诊断工作的一部分。通过IHC无确证FISH分析的MDM2的肿瘤表达有时（30％）足以达到诊断，但在大多数(57%)活检样本中,通过FISH证实了MDM2扩增.在4例（13%）患者切除之前，未明确诊断为去分化脂肪肉瘤。因为没有对相应的术前活检进行MDM2检测.
结论：当临床上不怀疑腹膜后肿瘤时，脂肪肉瘤诊断的组织学考虑可能被忽视。辅助免疫组织化学和细胞遗传学测试的实施可以最终导致在这种潜在的误导性解剖位置的明确诊断。
结果：本研究报告了从四个机构收集的肾脏内部或周围部位的一系列30个活检样本，其中正确诊断为高分化或去分化脂肪肉瘤。大多数（30个中的26个，87％）病变在活检取样中被准确诊断，所有这些都包括通过免疫组织化学（IHC）检测MDM2，荧光原位杂交（FISH）或两者的组合作为诊断工作的一部分。通过IHC无确证FISH分析的MDM2的肿瘤表达有时（30％）足以达到诊断，但在大多数(57%)活检样本中,通过FISH证实了MDM2扩增.在4例（13%）患者切除之前，未明确诊断为去分化脂肪肉瘤。因为没有对相应的术前活检进行MDM2检测.
结论：当临床上不怀疑腹膜后肿瘤时，脂肪肉瘤诊断的组织学考虑可能被忽视。辅助免疫组织化学和细胞遗传学测试的实施可以最终导致在这种潜在的误导性解剖位置的明确诊断。
