肺纤毛黏液结节性乳头状肿瘤2例临床病理分析及文献复习

Pulmonary ciliated muconodular papillary tumor: clinical pathologic analysis of two cases and review of literature

目的 :探讨肺纤毛黏液结节性乳头状肿瘤(ciliated muconodular papillary tumors,CMPT)的临床和病理组织学特征、免疫表型及鉴别诊断。方法:总结2例CMPT患者的临床病理资料,分析其临床表现、影像学特点、病理学特征及免疫表型,并结合相关文献进行探讨。结果:术中冷冻病理检查结果,1例患者诊断为微浸润性黏液腺癌,另1例考虑需鉴别CMPT与微浸润性黏液腺癌。术后石蜡组织显示其具有共同的特征性结构,肿瘤组织主要排列呈腺管状、乳头状结构,局部可呈贴壁状生长,也可形成微乳头状结构;肿瘤内及肿瘤周围肺泡腔内充满黏液,并形成黏液池;肿瘤间质常伴有淋巴细胞、浆细胞浸润;肿瘤由基底细胞、纤毛柱状细胞及黏液细胞3种细胞构成。3种肿瘤细胞均无异型性,无核分裂象,无肿瘤性坏死。免疫组织化学检查提示基底细胞表达P63及P40,部分表达TTF-1;纤毛柱状细胞及黏液细胞均表达CK7及MUC-1,部分或少数弱表达TTF-1、NapsinA、SP-A及P63,均不表达P40,少量纤毛细胞弱表达MUC5AC;3种细胞Ki-67均低表达。结论:肺CMPT是一种新近认识的少见肺肿瘤,其组织形态及免疫表型均具有特征性,3种肿瘤细胞的免疫组化表达不一致,但在影像学检查及术中冷冻病理检查中易被误诊为腺癌,确诊需要进行石蜡组织形态学观察和免疫组化标志检测。

Objective: To investigate the clinical manifestation, pathological feature, immunophenotype and differential diagnosis of ciliated muconodular papillary tumor(CMPT). Methods: Clinical data from two cases of CMPT were collected and analyzed retrospectively, including clinical and pathologic features, imaging findings and immunophenotype.Results: In frozen section examination during operation, one case was diagnosed as minimally invasive mucinous adenocarcinoma, and the other was considered as CMPT or minimally invasive mucinous adenocarcinoma. Histologic findings of paraffin embedded tissue sections revealed that the tumor consisted of papillary and glandular architecture, a minimal extent of micropapillary structure and discontinuous lepidic growth. There was abundant extracellular mucin surrounding the tumor, which formed pools of mucin, with chronic inflammatory cell infiltration in the stroma. The epithelial components of the lesion consisted of ciliated columnar cells, mucous cells, and basal cells. The basal cells provided a scaffold in the outer layer, the ciliated columnar cells and mucous cells intermingled at the surface of the glandular/papillary structures. All three types of cells showed no nuclear atypia and no mitotic figures. Tissue necrosis was not observed. The basal cells expressed P63 and P40, while a subset of basal cells expressed TTF-1. Both ciliated columnar cells and mucous cells expressed CK7 and MUC-1, whereas TTF-1, Napsin A, SP-A and P63 showed a patchy moderate intensity staining and P40 showed no staining. The ciliated columnar cells were focally positive for MUC5 AC. All three types of cells showed a low Ki-67 index. Conclusions: CMPT of lung is a newly defined and extremely rare tumor with characteristic histological findings and immunophenotype. There is a potential diagnostic pitfalls for CMPT because it is easily misdiagnosed as muci-nous adenocarcinoma by imaging findings and in the frozen section examination. The accurate pathologic diagnosis de-pends on the morphologic characteristics of paraffin-embedded tissue section and immunohistochemical staining.