组织学图像较一致，肿瘤表面部分可见宫腔表面黏膜上皮。

 本例的初步病理诊断为：类似卵巢性索瘤的子宫肿瘤，本例没有明确的经典的子宫间质肿瘤的成分，几乎全部为性索样分化的组织形态，一般为良性经过。

谢谢各位老师的回复，按照杨斌老师提供的文献将再做一次免疫组化。

Interesting case! Thank you for sharing.

I agree with most opinion here that this is most likely a UTRODCT (Uterine tumor resembling ovarian sex cord tumor). Based on recent studies and progress, this tumor further divided into two groups of tumors: 1. Endometrial stromal tumor with sex cord-like elements (ESTSCLE); 2. UTROSCT.

In ESTSCLE, the sex cord component constitutes a minor portion of an endometrial stromal tumor. In UTROSCT, it is predominant or exclusive component of a uterine wall lesion composed of a variety of mesenchymal elements. Therefore, UTROSCT is pathogenetically more heterogenous. To differentiate this tumor from usual smooth muscle or endometrial stromal tumor, it is important to confirm the sex-cord element. A panell of following 4 immunohistochemical markers is recommended as the most reliable markers for confirming sex cord component: Calretinin, CD99, Inhibin and MelanA. Among them Caretinin is the most sensitive marker. ESTSCLE usually only expresses one maker, mostly calretinin. Calretinin positivity plus any one of three other markers mentioned above may thus confirm the diagnosis of UTROSCT.

There is a good review paper just published on International Journal of Gynecologic Pathology in 2008 by Dr. Czernobilsky. I have the PDF file. If anybody interested in reading this paper, please send me an email and leave your email address to me.

I hope this is helpful to you all.

This is an unusual case of uterine mesenchymal neoplasm. The gross appearance is a submucosal polypoid nodule measuring 6 x 3 x 2 cm, separated from its endometrial attachment in and filling the endometrial cavity. Cut surfaces show focal cystic change. The microscopic features include hypercellularity, hyalinized fibrosis, relatively uniform cells with oval nuclei and often clear cytoplasm. Some neoplastic cell nests have peripheral palisading, and some cells form cord-like structure between collagenous connective tissue. Caldesmon-heavy chain, smooth muscle-specific actin, desmin, pancytokeratins and CD99 are all positive, but AE1 is negative. CD10, in my opinion, is negative. Tumor cells in some areas are more pleomorphic with enlarged and hyperchromatic nuclei, but I do not see mitotic activity or coagulative necrosis. The anatomic location and microscopic features of the lesion point towards a neoplasm of either unclear malignant potential (STUMP or endometrial stromal nodule) or low grade malignancy (low grade leiomyosarcoma or low grade endometrial sarcoma). This tumor is unusual in that histopathology does not clearly point towards smooth muscle differentiation (I favoror this) or endometrial stromal differentiation. Certainly, some tumors may show both smooth muscle and endometrial stromal differentiation. Before I render my final opinion, please try to answer the following questions for me:

1. Can you find the attachment site of the polypoid tumor and endometrium? If so, this interface needs to be examined under microscope very carefully. If not, the apparently uninvolved endometrium should still be examined to see if one can find the interface between the nodule and normal mucosa or myometrium. This is to see if there is any infiltrative growth by neoplastic cells.

2. I do not see a single mitosis in all the photos. Is this true? Can you give an average mitotic count in "hot" zones in terms of how many per 10 high-power fields? Can you select a "hot" area and do MIB-1 labeling?

3. Is there any area of necrosis?

Thank you for sharing this very interesting case with all of us.

（这是一例少见的子宫间叶性肿瘤。大体：粘膜下息肉样结节，6*3*2.5cm，隔以内膜附着并充填宫腔。切面：灶性囊性变。镜下：细胞丰富，玻变、纤维化，细胞相对一致，核卵圆形，胞浆多透明。一些肿瘤细胞巢有周边栅栏状排列，另一些细胞在胶原结缔组织之间形成性索样结构。caldesdom、SMA、desmin、panCK和CD99均阳性，AE1阴性。我认为CD10阴性。肿瘤细胞在某些区域多形性增大，核深染，但未见核分裂或凝固性坏死。结合这一例病变的解剖部位和镜下特点，倾向于恶性潜能未定（STUMP或子宫内膜间质结节）或低度恶性（低级别平滑肌肉瘤或低级别子宫内膜间质肉瘤）。这一肿瘤罕见之处在于，不明确向平滑肌分化（我的倾向）或子宫内膜间质分化。当然，一些肿瘤可以同时有平滑肌分化和子宫内膜间质分化。在我给出最后意见之前，请先回答以下问题：
1、能发现这个息肉样肿瘤和内膜之间的附着部位吗？如果能，需要非常仔细地在镜下检查它们的交界部位。如果不能，也应检查明显未被累及的子宫内膜，以观察是否能找到结节与正常粘膜或肌层的界限。目的是观察肿瘤细胞是否存在浸润性生长。
2、所有图片未见到核分裂。确实如此吗？可以给出活跃部位的平均核分裂计数（/10hpf）吗？可以选择活跃部位并检测MIB-1吗？
3、存在任何区域的坏死吗？
谢谢为大家分享如此有趣的病例。

--abin译）

 重新做了免疫组化，结果如下，图片后面在这里补上：

广谱CK 弥漫阳性，CD10部分阳性，抑制素a阴性，caldesmen 部分阳性