肺透明细胞肌黑色素细胞瘤临床病理分析

Clear cell myomelanocytic tumor of the lung

目的报道1例肺透明细胞肌黑色素细胞瘤,探讨其临床病理特点及病理诊断标准。方法通过HE染色、组织化学及免疫组化标记,观察肺透明细胞肌黑色素细胞瘤病理学特点。结果肿瘤细胞以梭形为主,其间可见大片透明细胞。细胞核短梭形或圆形,核仁明显。核分裂像少于2个/10HPF。肿瘤内血窦丰富,呈典型花边样(lace-like)结构。组织化学及免疫组化结果显示:透明细胞内富含糖原,PAS染色阳性;肿瘤细胞Melan-A及Melanoma(Pan)强阳性,HMB45灶性强阳性,Vimentin及Actin阳性,S-100、Syn阴性。结论肺透明细胞肌黑色素细胞瘤是肺内血管周细胞肿瘤家族中的一新成员,而非肺透明细胞“糖”瘤的新亚型。

Objective To characterize the clinical pathologic property of pulmonary clear cell myomelanocyte tumor and to ascertain its pathologic criterion, one case was reported with literature review. Methods This case was observed with HE, histochemical and immunohistochemistry stains. Results The neoplasm was composed of spindle cells with eosinophilic cytoplasm and the sheets or nests of epithelioid cells containing clear cytoplasm and distinct cell borders. The nuclei were round or short spindle, with distinct nucleoli. Rare mitoses were identified, which were less than two in 10 high-power fields. The tumor had abundant capillary-sized vessels, showing a characteristic and distinct lace-like pattern. The histochemical stain displayed PAS positive reaction, demonstrating intracytoplasamic glycogen. The immunohistochemical results showed that neoplastic cells expressed both smooth muscle and melanocytic marker. Briefly, tumor cells were diffusely positive for the MelanA, Melanoma （Pan）, Vimentin and Actin, focal expression of HMB-45. In contrast, S-100 protein and Syn were absent. Conclusions The myomelanocytic tumor is a new member of the perivascular epithelioid cell of lung, rather than a new subtype of clear cell ＂sugar＂ tumor.