最终结果：富于糖原的透明细胞癌。PAS＋＋＋

 浸润性导管癌。

色素没有固定的定位。不是恶黑

This appears to be a ductal carcinoma of mammary gland. Though no definite stromal invasion is appreciated in the photos uploaded, I suspect there is sich evidence at the tumor's periphery. The neoplastic cells form large and small nests with clearcut epithelial differentiation. Many cells have plump vacuolated cytoplasm compressing small eccentric nuclei. I am not certain, but these cells may have either cytoplasmic lipid droplets or mucin production. A simpla mucicarmine stain and PAS stain with diastase pretreatment should clarify the possibility of cytoplasmic mucin. Immunohistochemical stain for expression of gross cystic disease fluid protein-15 should be very informative. If positive with any of these stains, it's sufficient for the diagnosis of mammary ductal carcinoma. I doubt this could be a melanoma. The pigments seen are probably formalin pigments.

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    这似乎是乳腺导管癌。虽然上传的图片没有明确的间质浸润，我想，在肿瘤周边会有间质浸润的证据。肿瘤细胞形成大大小小的具有明确上皮分化的巢。许多细胞的胞浆丰富、含有空泡，核受挤偏位。虽不能确定，但这些细胞可能有胞质脂滴或黏液分泌。简单的粘液卡红染色及淀粉酶消化后PAS染色可证明粘液胞质。GCDFP-15免疫组化染色会很有用。如果这些染色任何阳性，就足以诊断乳腺导管癌。我对黑色素瘤表示怀疑，看到的色素可能是福尔马林色素。(福星高照）

 图1右上角好像有少量乳腺导管，还是考虑乳腺来源肿瘤可能性大。

肿瘤可以见到巢状排列（图4图5），细胞浆丰富，透亮，感觉分泌比较旺盛，从常见肿瘤的角度分析，还是首先考虑癌比较安全。至于后面图中的色素，好像间质内也有，是福尔马林色素？含铁血黄色？肿瘤累及皮肤吞噬的黑色素？其实浸润性导管癌细胞也可以有少量色素。恶性黑色素瘤要考虑（任何肿瘤内出现色素可能都要想到恶性黑色素瘤的可能，恶黑的形态实在是太复杂，而且此例细胞核仁也很明显），免疫组化可以明确。

 不知肿块与表皮有无联系？首先考虑恶黑。