鉴别无色素性恶性黑色素瘤方法的探讨

无色素及少色素性恶黑鉴别诊断时，（１）组织化学铁反应，褪色素和黑色素银染对证实瘤细胞中黑色素是有帮助的，但不能从无色素性恶黑中检出黑色素。因此对无黑色素恶黑的诊断和鉴别诊断帮助不大。网状纤维染色良性病均有增加，而恶黑几乎没有增加或仅极少增加。因此网状纤维染色有助于良恶性的鉴别。（２）免疫组化Ｓ－１００１８例恶黑及６例良性痣均显示阳性，这对无色素恶黑的诊断是有价值的，但对色素痣的恶变帮助不大。１６例恶黑中１４例色素性与１０例无色素性恶黑ＨＭＢ４５均显示阳性，证明两者有共同抗原，总阳性率８７．５％，６例良性痣均为阴性，证明无ＨＭＢ４５抗原。结果提示ＨＭＢ４５免疫组化检测不仅对无色素及少色素性恶黑的诊断与鉴别诊断实用性大，还可以用于对恶黑与良性痣、良性痣恶变的鉴别。（３）本组４例无色素性恶黑电镜下均找到前黑色素小体。因此在其他方法诊断困难时，应用电镜检查对确诊具有决定性作用。

A STUDY ON THE METHODS OF DIFFERENTIATING THE AMELANOTIC MALIGNANT MELANOMA

In the paper, we have studied and discussed the methods of the histologic diagnosis anddifferential diagnosis of malignant melanoma (MM). (1) Histochemically, iron reaction,f.ading pigment and silver stain can verify the pigment in the MM, but can't tell the pigmentin the amelanotic MM, so these methods have little value in the diagnosis and differential diagnosis of the amelanotic MM. The reticulum stain may be of benefit in differentiating thebenign from malignant tumors, for there is much more reticulum in benign nevus than inMM. (2) Immunohistochemically, S--100 stain demonstrates that 18 cases of MM and 6 cases of benign nevi are all positive, so it is useful in the diagnosis of the amelanotic MM, butnot in the malignant transformation of nevus. Of 16 cases of MM, 14 cases of rnelanotic andamelanotic MM are positive for HMB45 antigen, which proves that both of them have thesame antigen, the positive rate is 87. 5%. However, 6 cases of benign nevi are all negative.The results suggest that the immunohistochemical detection for HMB45 is valuabl.e not onlyin the diagnosis and differential diagnosis of melanotic and amelanotic MM, but also indistinguishing MM from benign nevus and its malignant transformation. (3) Under electromicroscopy I the 'melenosomes are found in all of 4 cases of amelanotic MM, and this methodis reliable and decisive in the diagnosis of amelanotic MM.