METHODS: This report describes a case of a 72-year-old man with a history of asbestos exposure who presented with pleural effusion as the first symptom and was eventually diagnosed as mesothelioma. Mesothelioma was suspected owing to prominent cell-in-cell engulfment in mesothelial cells on the first cytological sample, and the diagnosis of mesothelioma in situ was confirmed by histology. Unexpectedly, sarcomatoid morphology of mesothelioma was found in the second pathology samples 9 months after the first pathological examination. Both the mesothelioma in situ and invasive lesion showed immunohistochemical loss of methylthioadenosine phosphorylase (MTAP) and homozygous deletion of cyclin dependent kinase inhibitor 2A (CDKN2A) on fluorescence in situ hybridization. The patient received medication therapy but died of disease progression 12 months after the diagnosis of the sarcomatoid morphology of mesothelioma.
CONCLUSIONS: Our case suggests that cell-in-cell engulfment can be conspicuous in early-stage mesothelioma with inconspicuous nuclear atypia and few multinucleated cells. In addition, the presence of MTAP loss and CDKN2A homozygous deletion are suspected to be involved in early formation to invasive lesions and/or sarcomatoid morphology. We believe that it is important to consider genetic abnormalities when deciding on individual patient management. Furthermore, cases of mesothelioma, even those of an in situ lesion, with MTAP loss and/or CDKN2A deletion should be carefully followed up or subjected to early treatment.
方法:本报告描述了一例72岁男性,有石棉暴露史,以胸腔积液为首发症状,最终被诊断为间皮瘤。怀疑间皮瘤是由于在第一个细胞学样品中间皮细胞中明显的细胞吞噬,通过组织学证实了原位间皮瘤的诊断。出乎意料的是,首次病理检查9个月后,在第二次病理样本中发现间皮瘤的肉瘤样形态。在荧光原位杂交中,原位间皮瘤和浸润性病变均显示甲硫腺苷磷酸化酶(MTAP)的免疫组织化学丢失和细胞周期蛋白依赖性激酶抑制剂2A(CDKN2A)的纯合缺失。患者接受药物治疗,但在诊断间皮瘤肉瘤样形态12个月后因疾病进展而死亡。
结论:我们的病例表明,细胞间吞噬在早期间皮瘤中可能很明显,核异型不明显,多核细胞很少。此外,MTAP缺失和CDKN2A纯合性缺失的存在被怀疑与浸润性病变和/或肉瘤样形态的早期形成有关.我们认为,在决定个体患者管理时,考虑遗传异常是很重要的。此外,间皮瘤病例,即使是原位病变,与MTAP丢失和/或CDKN2A缺失应仔细随访或进行早期治疗。