This is an unusual case of surgical pathology. To resect any portion of the brachial plexus risks significant neurologic deficit in the corresponding upper extremity. Unless it is for a neoplastic process confirmed by frozen section of a biopsy during surgery, this procedure is rarely done. Although there is lymphocytic infiltration in the perineurium and soft tissue between nerves, these lymphocytes are small and do not show significant nuclear enlargement or atypia. I am not certain whether the infiltration seen in Figures 1 ans 2 are endoneurial or not. The nerves themselves appear unremarkable. Other than the fact that it is very unusual to see lymphocytic infiltration in perineurium  and deep soft tissue (fat), I am not certain of the cause or the clinical significance of the infiltrates observed. Could this be a manifestation of chronic lymphocytic leukemia? Immunohistochemical stains (CD45, CD3, CD20, CD10, CD79a) may help.

 我们针对神经束以外的弥漫性小圆细胞做免疫组化，结果为：LCA（+），CD3（-），CD20（散在+），CD79a（-）,CK（-）,SYN（-）,CGA（-）,S-100（神经束+）。

我们依然不清楚是什么病变，请mjma老师再点评！

If these small lymphocytes do not have a majority of B or T cells, leukemic infiltration is not likely. I would make sure the patient does not have a history of CLL, and his current CBC is normal without leukocytosis. If so, these non-neoplastic infiltrates may reflect chronic inflammation, which is a very odd think to take place in the brachial plexus. I don't really know what would have caused this.

图像辨认得不是很确切，本人考虑：神经组织似乎是正常的，感觉之间的非神经组织成份是异常的。图像的第一印象是小淋巴细胞样的成份有问题。如果免疫组化能证实那些小淋巴样细胞是单一类型的小淋巴细胞，那可能就提示淋巴瘤。如果，是混合型的小淋巴细胞增生，那么提示炎性假瘤可能。

另外，请问有没有特殊的病史？

低倍镜下看，也让人想起两种病：丛状神经纤维瘤、创伤性神经纤维瘤，但是，中倍镜下、综合各图来看，觉得基本排除这两种病的 可能。

既然LCA是阳性的，而CD3、CD20都不算阳性，那么是不是还要考虑到排除浆细胞肿瘤、粒细胞肿瘤的可能？建议，多做几种淋巴细胞的表型标记。LCA确实是阳性吗？或者，要不要考虑其他分化差的肿瘤？另外，病人全身其他情况如何？有没有别的特殊病史——排除肿瘤转移灶可能？血象？