Abstract：
Pituitary neuroendocrine tumors (PitNETs) lacking lineage affiliation are termed \"null cell\" PitNETs (NCTs). NCTs are characterized as being immunonegative for pituitary hormones as well as transcription factors. We analyzed the ultrastructure and immunohistochemistry of six hormone-negative and transcription factor (TPIT, PIT1, SF1)-negative PitNETs, with less than 1% immunoreactive cells. Histologically, three cases presented a perivascular pattern and pseudorosettes; the other three showed a solid pattern with oncocytic changes. Electron microscopic examination revealed poorly differentiated tumor cells with sparsely scattered secretory granules and intracellular organelles in all null cell tumors when compared with hormone-positive PitNETs. Two cases harbored a honeycomb Golgi (HG) structure, and three oncocytic tumors showed mitochondrial accumulation. The two HG cases were immunopositive for newly obtained TPIT (CL6251) and showed some adrenocorticotropic hormone-positive cells, while the remaining four were diffusely immunopositive for GATA3, with two SF1-positive cases identified in subsequent immunostaining. Thus, these six cases may be classified as two sparsely granulated corticotroph PitNETs, two gonadotroph PitNETs with SF1 re-staining, and two likely gonadotroph PitNETs with GATA3 immunostaining. No \"true NCT\" was detected among 1071 PitNETs, demonstrating the importance of precise diagnosis following the most recent criteria to improve therapeutic success.
摘要：
缺乏谱系联系的垂体神经内分泌肿瘤（PitNETs）被称为“空细胞”PitNETs（NCTs）。NCTs的特征是对垂体激素以及转录因子免疫阴性。我们分析了六种激素阴性和转录因子（TPIT，PIT1,SF1)-负PitNET,具有小于1%的免疫反应性细胞。组织学上,3例表现为血管周围模式和假结节性;另外3例表现为伴有嗜酸性细胞改变的实体模式。与激素阳性PitNETs相比，电子显微镜检查显示，在所有无效细胞肿瘤中，分化差的肿瘤细胞具有稀疏分散的分泌颗粒和细胞内细胞器。两例有蜂窝状高尔基（HG）结构，三个嗜酸性细胞肿瘤显示线粒体积累。两例HG新获得的TPIT（CL6251）免疫阳性，并显示一些促肾上腺皮质激素阳性细胞，其余4例GATA3弥漫性免疫阳性，在随后的免疫染色中发现2例SF1阳性病例。因此，这6例可能被归类为两个稀疏颗粒的促肾上腺皮质激素PitNETs，两种促性腺激素PitNETs用SF1重新染色，和两个可能的促性腺激素PitNETs用GATA3免疫染色。在1071个PitNET中没有检测到“真正的NCT”，证明了按照最新标准进行精确诊断以提高治疗成功率的重要性。
