Ovarian Serous Cystadenofibroma With Signet Ring-Stromal Cells: Report of 2 Cases

Unusual Ovarian Tumors With Endometrioid Proliferations Co-Expressing Estrogen Receptor and CDX-2 Arising in Cystadenofibromatous Background: Report of 3 Cases

This report describes 3 cases of ovarian tumors with unusual glandular proliferations co-expressing estrogen receptor and CDX-2 by immunohistochemistry set in cystadenofibromatous background. Targeted next-generation sequencing was performed on the cyst lining epithelium and glandular proliferations for all cases; CTNNB1 mutations were detected in the glandular proliferations of all neoplasms. The cyst lining of case 1 demonstrated a different CTNNB1 mutation from the matched glandular proliferation. No mutations were detected in the cyst lining from case 2. The cyst lining and glandular proliferation for case 3 harbored identical ATM and PIK3CA mutations with an additional CTNNB1 mutation in the glandular proliferation. To our knowledge, this is the first reported series of endometrioid proliferations with co-expression of estrogen receptor and CDX-2 in cystadenofibromatous background.

Ovarian Signet-ring Stromal Tumor: A Morphologic, Immunohistochemical, and Molecular Study of 7 Cases With Discussion of the Differential Diagnosis

Signet-ring stromal tumor (SRST) is a rare ovarian stromal neoplasm characterized by a population of bland signet-ring cells, devoid of mucin or lipid, in a generally cellular fibromatous stroma. Previous reports have described heterogenous immunohistochemical and molecular genetic findings, including occasional nuclear β-catenin expression and/or CTNNB1 mutations. We report 10 ovarian stromal neoplasms originally diagnosed as SRST. All but 1 tumor underwent detailed immunohistochemical analysis (including β-catenin) and 5 of 10 had CTNNB1 mutation analysis performed. All tumors contained a population of morphologically bland signet-ring cells that ranged from 15% to 95% of the neoplasm, characterized by a single large empty intracytoplasmic vacuole, mostly with nuclear indentation. Six of the 10 tumors contained cellular fibroma-like areas, comprising from 10% to 85% of the neoplasm. Three of the 10 tumors were reclassified as microcystic stromal tumor with signet-ring cells on the basis of the microcyst formation and hyalinized stroma, beta-catenin and cyclin D1 nuclear expression and/or CTNNB1 mutation, CD10 staining and largely absent expression of inhibin and calretinin. In the remaining 7 tumors, the diagnosis of SRST remained, constituting the largest series of SRST reported in the literature to date. The results of our study suggest that a subset of tumors diagnosed as ovarian SRST, especially those which show β-catenin nuclear positivity and/or CTNNB1 mutation, likely represent microcystic stromal tumor with variant morphology. We also suggest that at least a subset of SRSTs without evidence of Wnt/β-catenin pathway abnormalities may be related to ovarian fibromas. We discuss the differential diagnosis of ovarian neoplasms containing signet-ring cells.

Bilateral Signet-ring Stromal Tumor of the Ovary: A Case Report With Next-generation Sequencing Analysis and FOXL2 Mutation Testing

Signet-ring stromal tumor (SRST) is a rare benign stromal neoplasm of the ovary with only a handful of cases reported in the literature. To date, all but one reported cases have been unilateral, and the pathogenesis and underlying genetic abnormalities of this entity are not well characterized. Here we report a case of a 70-yr-old woman with bilateral ovarian SRST, clinically presenting with abdominal distention and rectal bleeding, and bilateral ovarian masses on imaging studies. Total hysterectomy and bilateral salpingo-oophorectomy were performed, revealing bilateral solid ovarian tumors with characteristic signet-ring cell morphology. The immunohistochemical profile-positive steroidogenic factor 1, calretinin, and smooth muscle actin, and negative epithelial membrane antigen-supported the diagnosis of SRST. CTNNB1 mutation and abnormal nuclear beta-catenin expression have recently been reported in 2 SRSTs. However, we did not identify any mutations in 54 oncogenes and tumor suppressor genes (including CTNNB1) by next-generation sequencing analysis, and PCR Sanger sequencing did not reveal FOXL2 C134W mutation, suggesting the possibility of heterogenous pathogenesis of these tumors.

Identification of Signet Ring Cell Change in Colonic Subserosa in the Setting of Clostridium difficile Colitis

Signet ring cell change of intestinal epithelial cells is a rare but well-known mimicker of signet ring cell carcinoma and is often associated with ischemic and/or pseudomembranous colitis. Instead, signet ring cell change involving nonepithelial cells in the subserosa of the intestine is an extremely rare finding with only a single case report in the literature to date. We report a new case of benign signet ring cell change localized in the subserosa of the large bowel incidentally identified in a resection specimen for Clostridium difficile colitis mimicking a metastatic signet ring cell carcinoma. Based on the morphologic features and immunohistochemical profile, we propose that these signet ring cells may possibly represent modified/degenerated fat cells. Furthermore, we discuss how to differentiate benign signet ring cells from a signet ring cell carcinoma.

Perspectives on signet ring stromal cell tumor and related signet ring cell lesions of the gonads

In this article, we discuss advances in our knowledge of the pathology of signet ring stromal cell tumor and related signet ring cell lesions of the ovary and a single case of signet ring stromal cell tumor of the testis. We divide ovarian signet ring cell lesions into 3 categories that reflect differences in their pathogenesis and histologic appearance. With 1 exception, all authentic cases of signet ring stromal cell tumor have been unilateral. Cases of ovarian signet ring stromal cell tumor from the literature can arise in 2 ways. The majority of cases arise multifocally from fibroma, whereas the remainder likely arise directly from the ovarian stroma. In difficult cases, immunocytochemistry provides improved diagnostic accuracy in distinguishing signet ring stromal cell tumor and its mimics from Krukenberg tumor. The most useful antibodies in this regard are epithelial membrane antigen and vimentin.

On the pathogenesis of sclerosing stromal tumor of the ovary: a neoplasm in transition

Sclerosing stromal tumor (SST) is a distinctive benign ovarian stromal neoplasm first reported in 1973. Although its initial description supports its characterization as an ovarian stromal tumor, its exact pathogenesis remains uncertain. It is usually hormonally inactive, but occasional tumors are estrogenic or androgenic, and virilization can occur during pregnancy. We report 11 cases of SST, 6 of which were associated with another type or other types of ovarian stromal tumor. In 4 of these, a transition from thecoma of either typical or luteinized type to SST was observed. Our index case was that of a 16-yr-old girl who had a typical thecoma that underwent involutional changes in an extensive subserosal portion of the tumor with conversion to SST. In our series, 3 cases of SST underwent transformation to ovarian myxoma, one of which also contained a component of thecoma. The active SST components stained for inhibin, steroidogenic factor 1, and α-smooth muscle actin, but were negative or occasionally weakly positive for desmin.