首先考虑未分化癌，免疫组化排除NHL及其他肉瘤。

The neoplasm is clearly malignant with readily seen mitotic figures, focal necrosis, and cellular pleomorphism. Though figures 8 and 9 display large and plump or elongated malignant cells with occasional binucleation, and figure 10 suggest squamous differentiation that are suggestive of anaplastic or poorly differentiated thyroid carcinoma, figures 4, 5 and 6 show cellular nesting between sinusoidal delicate blood vessels suggestive of neuroendocrine differentiation. I am not certain, but figures 2 and 6 show small eosinophilic concretions of possible amyloid material. These bring the important diagnosis of medullary carcinoma into considertaion. Certainly medullary carcinoma of thyroid doesn't have to show abundant amyloid or associated foreign body giant cell reaction, which apparently are absent in this case. Medulloblastomas consist of neoplastic cells with uniform or varying histology - spindled, oncocytic, epithelioid, neuroendocrine or even giant cells. I do not think papillary thyroid carcinoma, follicular thyroid carcinoma, lymphoma or plasmacytoma is the likely diagnosis, and would confirm or rule out my suspicion by immunohistochemistry (calcitonin, thyroglobulin, synaptophysin, NSE and chromogranin A).            学习并翻译mjma老师内容：  
  肿瘤明显恶性,因为易见核分裂像、局灶性坏死、细胞丰富和多形性显著。图8、9中显示大的、肿胀的或拉长的细胞及少数双核细胞，图10示鳞状分化提示间变性或低分化甲状腺癌。图4、5、6示细胞丰富的巢位于窦内纤细血管之间，提示神经内分泌分化。图2和6中有少量嗜酸性、可能为淀粉样物质沉着，虽然不能确定，但这些线索要考虑髓样癌。当然甲状腺髓样癌不一定有大量的淀粉样物质沉着和异物巨细胞反应，此病例中就缺少这些变化。甲状腺髓样癌有一致的或多种组织学：由梭形细胞、嗜酸性细胞、上皮样细胞、神经内分泌细胞、甚至巨细胞等肿瘤细胞组成 。我认为不能诊断甲状腺乳头状腺癌、滤泡性甲状腺癌、淋巴瘤或浆细胞瘤。可通过做免疫组化(降钙素,甲状腺球蛋白,突触素,NSE和嗜铬粒蛋白A)来证实或排除我的怀疑。

需要做免疫组化明确

考虑髓样癌
可通过做免疫组化

    我觉得间变癌可能性大!

考虑髓样癌

免疫组化结果：
CK  ( + ) ;  EMA  ( + ) ;  Vimentin  ( + ) .

诊断为甲状腺肉瘤样癌还是低分化癌？

 恶性肿瘤,期待结果

 甲状腺未分化癌=间变性癌=肉瘤样癌

 肉瘤样癌