Ⅰ型胸膜肺母细胞瘤1例报道并文献复习

Pleruopulmonary blastoma type Ⅰ:a case report and review of literatures

目的探讨Ⅰ型胸膜肺母细胞瘤的临床病理特征。方法大体及镜下观察,结合SP法免疫组化染色并文献复习。结果患儿,女,3岁11月,临床主要表现为左肺囊性肿物。组织学特征:大体表现为含气的单纯囊肿,囊肿内可见细分隔;镜检囊壁被覆良性上皮,其下为原始间叶细胞增生,可见明显的横纹肌母细胞分化,部分梭形细胞呈纤维肉瘤样改变,其余囊壁及细间隔主要为纤维结缔组织,部分被覆呼吸道上皮,可见平滑肌,灶性钙化,及多核巨细胞反应等良性改变。免疫组化染色原始间叶细胞desmin及myogenin阳性。结论Ⅰ型胸膜肺母细胞瘤形态学上貌似良性,预后较好,难与其他先天性良性肺囊肿区分,故应仔细观察多取材,镜下寻找囊壁内原始间叶成分,从先天性肺囊肿中分辨出这一罕见儿童恶性肿瘤具有重要临床意义。

Purpose To study the clinicopathological characteristics of pleuropulmonary blastoma type Ⅰ Methods Gross examination,microscopy,SP method immunohistochemistry were applied in a case of pleuropulmonary blastoma type I , with review of literatures. Results The patient was a 3 years and 11 months old girl. She presented with a cyst on her left lung. Grossly, type Ⅰ pleuropulmonary blastoma was an air-filled, delicate muhilocular cyst with thin septa. Microscopically, two foci of cyst walls were identified and proliferating primitive mesenchymal cells beneath the benign epithelium, with rhabodmyoblasts and fibrosarcoma-like features were seen. Other cyst walls composed of fibrous connective tissue lined by respiratory epithelium, and focal calcification and giant cell changes were detected within smooth muscle. Desmin and myogenin were positive in primitive mesenchymal cells by immunohistochemistry. Conclusions Pleuropulmonary blastoma type I has morphologically benign appearance, and good prognosis, which are difficult to differetiate from other congenital benign lung cysts. It is necessary to do thorough examination and submit more sections, and to look for primitive mesenchymal cell in cyst walls. There is clinical significance to distinguish this rare pediatric malignant tumor from other can- genital lung cysts.