认识胸腔内淋巴结的特殊情况，以免误诊，胸内淋巴结存在向神经内分泌细胞分化的干细胞吗？
Small Neuroendocrine Lesions in Intrathoracic  Lymph Nodes of Patients With Primary Lung
Adenocarcinoma: Real Metastasis?
(Am J Surg Pathol 2010;34:1701–1707)
Abstract: The presence of individual neuroendocrine cells in rare peripancreatic lymph nodes (LNs) suggests that neuroendocrine tumor or nested neuroendocrine cell proliferation can arise in situ from neuroendocrine cells native to any LN. However, it is very difficult to ascertain whether any neuroendocrine lesion in LNs is a primary tumor or a metastasis from adjacent organs.
We encountered 4 cases of neuroendocrine proliferation in intrathoracic LNs (ILNs) of patients with primary lung adenocarcinoma. All patients had a single lung mass without mediastinal lymphadenopathy based on computed tomography and
positron emission tomography imaging. Mediastinal staging was
done by either mediastinoscopy or thoracotomy and none of
them had metastasis from adenocarcinoma in any LN. One patient had three ILNs positive for neuroendocrine proliferation measuring 1.7, 1.8, and 4.0 mm, respectively and a minute
tumorlet less than 1.0mm in the lung. Three other patients had
small areas of neuroendocrine proliferation no more than 1mm
in single ILN without any lung neuroendocrine lesion.
Neuroendocrine cells in ILNs often formed nests of varying
size with similar morphology to carcinoid tumorlet in the lung.
Small clusters of neuroendocrine cells without any particular
pattern were often seen together with these nests. These cells
were positive for neuroendocrine markers: synaptophysin,
chromogranin, and CD56. They were also positive for CK7
and TTF-1. It is interesting to note, single cells positive for
neuroendocrine markers and TTF-1 were identified near or
away from these neuroendocrine nests or clusters. These findings
suggest that neuroendocrine lesion can be incidentally identified in ILNs. Close clinical follow-up is warranted as metastasis from or synchronous lesions in adjacent organs cannot be excluded.

谢谢！