用阿尔新蓝-番红花红(AB-S)、长时间甲苯胺蓝(LTB)、氯醋酸酯酶3种组织化学方法和电镜观察证实,人胎胸腺实质中存在肥大细胞,并分别作了计数。结果表明,皮质中肥大细胞数目较髓质多。用AB-S染色,胞质内含阿尔新蓝阳性(蓝染)颗粒的肥大细胞数较含番红花红阳性(红染)颗粒的数目多。结合超微结构观察表明,胸腺实质中的肥大细胞颗粒特点符合胰蛋白酶阳性肥大细胞(TMC)类型。本文就其存在、数目和染色特性进行了讨论。 The histochemical and electron microscopic observations showed that there were mast cells in the thymus of human fetus and were respectively treated with AB-S, LTB and chloroacetate esterase Counting. The results show that the number of mast cells in the cortex is more than the medulla. With AB-S staining, the number of mast cells in the cytoplasm containing Alzheir-blue-positive (blue-stained) particles was larger than the number of saffron-positive (red-stained) particles. Combined with ultrastructural observation, the characteristics of mast cells in thymus parenchyma conform to the type of trypsin positive mast cells (TMC). This article discusses the existence, number, and staining characteristics.