07年右卵巢肿物：

 Microcystic stromal tumor of the ovary: report of 16 cases of a hitherto uncharacterized distinctive ovarian neoplasm

Am J Surg Pathol
Irving, J. A. Young, R. H.

We have encountered 16 ovarian neoplasms of probable stromal origin whose most distinctive feature is microcystic change, which is usually conspicuous. On the basis of our extensive experience with ovarian tumors, the neoplasm is unique and warrants separate categorization; we have elected to designate it "microcystic stromal tumor" because of its most striking feature. The patients ranged from 26 to 63 (mean 45) years of age and typically presented with a pelvic mass. Hormonal manifestations were possibly present in only 2. All tumors were unilateral with a mean size of 8.7 (range: 2 to 27) cm and none had evidence of extraovarian spread. The tumors were solid-cystic (11 cases), solid (3 cases), or predominantly cystic (2 cases). The solid component was usually firm and tan or white-tan, but in 1 case was yellowish; soft foci were present in 3 cases and small foci of hemorrhage, necrosis, or both, in 3. On microscopic examination the appearance of the tumors varied according to the relative prominence of their 3 fundamental components: microcysts, solid cellular regions, and fibrous stroma. Microcysts dominated in 9 cases, were roughly equal to noncystic morphology in 5 cases and were minor in 2. The microcystic pattern was characterized by small rounded to oval cystic spaces, in areas coalescing to larger irregular channels; intracytoplasmic vacuoles were also frequently present. The solid cellular areas were usually focally intersected by fibrous bands and hyaline plaques reminiscent of thecoma. The cells contained moderately conspicuous finely granular, lightly eosinophilic cytoplasm, with generally bland, round to oval or spindle-shaped nuclei with fine chromatin and small indistinct nucleoli. Foci of bizarre nuclei were, however, present in 10 cases. Mitotic rate was low in all cases, ranging from 0 to 2 mitoses/10 high-power fields. Immunohistochemical results were as follows: CD10, 16/16 cases positive; vimentin, 16/16 cases positive; inhibin, 1/16 cases weakly positive; calretinin, 1/16 cases positive; cytokeratin, 4/16 cases focally positive; and epithelial membrane antigen, 0/16 cases positive. Microcystic change can be observed in a wide variety of ovarian tumors and the broad potential differential diagnosis is discussed in the text. For tumors which have been well sampled and exhibit (1) a microcystic pattern and regions with lobulated cellular masses with intervening, sometimes hyalinized fibrous stroma, (2) an absence of morphologic features enabling any other specific diagnosis in the sex cord-stromal category, (3) an absence of epithelial elements, and (4) an absence of teratomatous or other germ cell elements, we propose the designation "microcystic stromal tumor." The characteristic immunophenotype is CD10/vimentin+/epithelial membrane antigen-, with focal cytokeratin-positivity in one-quarter of cases; inhibin and/or calretinin are usually negative. Seven patients with available follow-up are without evidence of disease at a mean of 4.25 years (range: 1.5 to 12.5 y) from the time of initial diagnosis. These tumors, to date, have occurred over a wide age range in postpubertal females, are characteristically unilateral, and confined to the ovary at presentation. They represent, in addition to the sclerosing stromal tumor (segregated out 3 decades ago), a distinctive subtype of ovarian tumor, likely also belonging to the stromal category based on current evidence.

 Microcystic stromal tumor (MCST) is a recently described subtype of ovarian tumor characterized by prominent microcystic histologic pattern and diffuse immunoreactivity for CD10 and vimentin. However, its pathobiology, particularly its histogenesis, remains largely unclear. Here, we report 2 cases of ovarian MCST, in which we have performed extensive histologic, immunohistochemical, and genetic investigations to determine its distinct nature among ovarian neoplasms. The patients were 32 and 41 years of age. Both tumors were solid and cystic masses involving the right ovary. Microscopically, tumor cells with generally bland, round-to-ovoid nuclei grew in microcystic, macrocystic, and solid patterns. Intervening thick fibrous stroma was observed. Immunohistochemically, tumor cells were diffusely and strongly positive for CD10, vimentin, and Wilms tumor 1. Furthermore, we detected aberrant nuclear expression of β-catenin protein in both cases. Of interest, mutation analyses revealed the presence of an identical point mutation, c.98C>G, in exon 3 of β-catenin (CTNNB1) in both tumors. This is an oncogenic mutation that causes replacement of serine with cysteine at codon 33, leading to the loss of a phosphorylation site in the β-catenin protein. The results of this study strongly suggest that dysregulation of the Wnt/β-catenin pathway plays a fundamental role in the pathogenesis of ovarian MCST. Finally, by comparing the immunophenotype of MCST with its histologic mimics and other ovarian sex cord-stromal tumors, we were able to identify unique features of MCST and a panel of markers useful in differential diagnosis.

 此病例已撰写为病例报告，发表在Human Pathology杂志，链接：https://www.ncbi.nlm.nih.gov/pubmed/29458068

感谢各位网友的关注！

16年髂窝肿物：

 考虑脂肪肉瘤，静待各位老师讲解……

 补充免疫组化：CD99呈典型的核旁逗点状阳性

 07年的图像确实比较符合文献中描述的形态，细胞核染色细腻，有一些细小的染色质集结点，还有一些奇异型细胞核。16年的变化就比较大一些了，细胞密度增加，异型性增加。β-catenin（非正常的核质阳性）和CD10免疫还是支持的。MDM2核CDK4特异性不好，很多肿瘤都有阳性。

 07年卵巢微囊性间质肿瘤 (microcystic stromal tumor of the ovary

 Overlap of microcystic stromal tumor and primary solid pseudopapillary neoplasm of the ovary.

 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4637744/

 学习了，谢谢分享

 16年卵巢肿物：

 16年卵巢肿物IHC标记：Vimentin阳性，Ki67指数约15%+。CA125，AE1/3，CK7，CEA，inhibin，CD56，Syn，CgA均阴性。

16年髂窝肿物IHC标记：S-100散在细胞核阳性，CDK4阳性，MDM2阳性，Ki67指数约15%+。AE1/3，EMA，GFAP，CD56，Syn，CgA均阴性。

 CDK4阳性，MDM2阳性，似乎提示脂肪内容。但是，HE形态不支持，S100只有散在阳性，还有一个特点可能大家没有注意到，脂肪细胞和脂肪肿瘤Ki67呈胸膜/胞质阳性。

HE形态更像微囊性间质肿瘤，我们最近有一例，杨文涛教授在华夏病理十周年会议上讲过，它的免疫组化特点是CD10弥漫阳性，β-catenin 胞质+胞核阳性，可以试做一下。必要时请专家会诊。

 按Abin老师意见，补做CD10，β-catenin

 学习了，谢谢老师们的分享与点评