BACKGROUND Carcinosarcoma of pancreas is a rare subtype of pancreatic cancer. The aim of this study was to comprehensively elaborate the clinicopathological and molecular features of this rare malignancy. METHODS Patients who were diagnosed with carcinosarcoma of the pancreas were retrospectively identified from pathology database of a single institution between 2012 and 2018. RESULTS A total of nine patients were identified. Pathological examination of tumor tissues from included patients showed coexisting carcinomatous and sarcomatous components. These two components were distinguished by mutually exclusive expression of cytokeratin and vimentin. The sarcomatous tissue exhibited more extensive proliferation, as revealed by Ki67 staining, and necrosis compared with the carcinomatous counterpart. Genomic analysis of tumor tissues for two patients demonstrated hotspot mutation at KRAS and TP53. Carcinomatous and sarcomatous components were separately obtained via laser captured microdissection in one patient, and mutations of driving genes were highly concordant between them. Besides, immunostaining of frequently-altered tumor suppressor genes for these two components suggested consistent expression patterns. The median overall survival for six patients with adequate follow-up was 14 months. CONCLUSION Carcinosarcoma of the pancreas represent a rare malignancy with distinct histological characteristics. Genomic and molecular analysis suggested monoclonal origin of carcinomatous and sarcomatous components.

中文翻译：

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胰腺癌肉瘤：综合临床病理学和分子特征。

背景胰腺癌肉瘤是一种罕见的胰腺癌亚型。本研究的目的是全面阐述这种罕见恶性肿瘤的临床病理学和分子特征。方法从2012-2018年间单一机构的病理数据库中回顾性筛选确诊为胰腺癌肉瘤的患者。结果共筛选出9例患者。对纳入患者的肿瘤组织进行病理检查，发现癌性和肉瘤性成分并存。这两种成分的区别在于细胞角蛋白和波形蛋白的互斥表达。肉瘤组织表现出更广泛的增殖，如 Ki67 染色所揭示的，与癌对应物相比，坏死。对两名患者的肿瘤组织进行基因组分析，证明 KRAS 和 TP53 存在热点突变。1例患者通过激光捕获显微切割分别获得癌和肉瘤成分，驱动基因突变高度一致。此外，这两种成分的频繁改变的肿瘤抑制基因的免疫染色表明表达模式一致。6 名接受充分随访的患者的中位总生存期为 14 个月。结论胰腺癌肉瘤是一种罕见的恶性肿瘤，具有独特的组织学特征。基因组和分子分析表明癌和肉瘤成分的单克隆起源。1例患者通过激光捕获显微切割分别获得癌和肉瘤成分，驱动基因突变高度一致。此外，这两种成分的频繁改变的肿瘤抑制基因的免疫染色表明表达模式一致。6 名接受充分随访的患者的中位总生存期为 14 个月。结论胰腺癌肉瘤是一种罕见的恶性肿瘤，具有独特的组织学特征。基因组和分子分析表明癌和肉瘤成分的单克隆起源。1例患者通过激光捕获显微切割分别获得癌和肉瘤成分，驱动基因突变高度一致。此外，这两种成分的频繁改变的肿瘤抑制基因的免疫染色表明表达模式一致。6 名接受充分随访的患者的中位总生存期为 14 个月。结论胰腺癌肉瘤是一种罕见的恶性肿瘤，具有独特的组织学特征。基因组和分子分析表明癌和肉瘤成分的单克隆起源。6 名接受充分随访的患者的中位总生存期为 14 个月。结论胰腺癌肉瘤是一种罕见的恶性肿瘤，具有独特的组织学特征。基因组和分子分析表明癌和肉瘤成分的单克隆起源。6 名接受充分随访的患者的中位总生存期为 14 个月。结论胰腺癌肉瘤是一种罕见的恶性肿瘤，具有独特的组织学特征。基因组和分子分析表明癌和肉瘤成分的单克隆起源。