Serous Tubal Carcinogenesis: The Recent Concept of Origin of Ovarian, Primary Peritoneal and Fallopian Tube High-Grade Serous Carcinoma

Prophylactic Salpingectomy during Hysterectomy for Benign Disease: A Prospective Study to Evaluate High-Grade Serous Ovarian Carcinoma Precursors

Recent findings suggest that high-grade serous ovarian cancer can originate in the fallopian tube. Not only has that made the identification of precursor lesions pivotal in early detection and prevention of these cancers, prophylactic salpingectomy alongside hysterectomy for benign indications has been increasingly proposed as well. The present prospective single-center study included 273 women who underwent opportunistic salpingectomy alongside laparoscopic supracervical hysterectomy. Uterine and tubal histopathological results as well as intra- and postoperative complications were evaluated. The complication rate was 3.3%, of which none were caused by salpingectomy. Uterine histopathology diagnosed 181 patients (66.8%) with uterine myomas, 60 patients (22.1%) with adenomyosis, 29 patients (10.7%) with adenomyomatosis, and, 1 patient (0.4%) without pathological abnormality. p53 signatures were detected in 221 right fallopian tubes (80.9%) and in 229 left tubes (83.9%). In total, 8 patients showed bilateral STIL (2.9%), whereas in 1 patient (0.4%) STIL was detected in the left tube only. No STIC were detected. Laparoscopic opportunistic salpingectomy is demonstrated to be both safe and feasible. It appears to be promising to reduce the risk for ovarian cancer, yet more studies are needed to undoubtedly confirm this.

Bulky peritoneal carcinosarcoma with tiny high-grade serous carcinoma of the fallopian tube: a case report

Peritoneal carcinosarcoma is a highly aggressive and uncommon neoplasm that has carcinomatous and sarcomatous components; the malignancy rarely localizes to the omentum. We report a case of a bulky peritoneal carcinosarcoma with tiny high-grade serous carcinoma of the fallopian tube. A 60-year-old female with a huge pelvic mass (12 cm in diameter) underwent a total abdominal hysterectomy, bilateral salpingo-oophorectomy, and omentectomy for tumor debulking. Pathological findings showed minimally invasive high-grade serous carcinoma of the left fallopian tube and carcinosarcoma of the omentum. Similar p53 diffuse immunostaining in the omental carcinosarcoma and the tubal carcinoma provides evidence for a clonal relationship between the two neoplasias. This case suggests a small serous carcinoma, originating in the tubal mucosa, subsequently became implanted in the omentum and grew preferentially, converting to a carcinosarcoma at a remote site.

Frontiers in the Pathology and Pathogenesis of Ovarian Cancer: Cancer Precursors and "Precursor Escape"

This article summarizes the pathogenesis of ovarian carcinoma, focusing on the paradox of high-grade serous carcinogenesis. The fallopian tube is the prime site of origin in early serous cancers. Because a subset of serous cancers is associated with early serous proliferations absent intramucosal carcinomas, "precursor escape" is emerging, whereby some advanced cancers trace their roots to early serous proliferations. This has parallels in the endometriosis model and opens up a novel mechanism by which advanced malignancy could emerge without an obvious tubal carcinoma. The impact of this concept on classification of serous cancer and expectations from preventive strategies are discussed.

The fallopian tube, "precursor escape" and narrowing the knowledge gap to the origins of high-grade serous carcinoma

Most ovarian carcinomas are high-grade serous carcinomas (HGSC) that contain TP53 mutations, present at advanced stage, and eventually become resistant to chemotherapy. The rapid evolution of this disease has been attributed to an origin in the distal fallopian tube, in the form of serous tubal intraepithelial carcinomas (STICs). This has led to a disease model where malignancy develops first in the tube and spreads to the peritoneum or regional lymph nodes. However, although most early or incidentally discovered HGSCs manifest in the tube with STICs, many advanced HGSCs are not accompanied by a malignancy in the fimbria. To resolve this paradox, the focus has shifted to earlier, premalignant serous proliferations (ESPs) in the tubes, which lack the cytomorphologic features of malignancy but contain TP53 mutations. These have been termed p53 signatures or serous tubal intraepithelial lesions (STILs). Although they have not been presumed to have cancer-causing potential by themselves, some ESPs have recently been shown to share identical TP53 mutations with concurrent HGSCs, indicating a shared lineage between these early mucosal changes and metastatic malignancy. This discovery supports a paradigm by which HGSCs can emerge not only from STICs but also from exfoliated precursor cells (precursor escape) that eventually undergo malignant transformation within the peritoneal cavity. This paradigm unifies both localized and widespread HGSCs to a visible pre-existing cellular alteration in the tubal epithelium, and highlights a consistent and necessary biologic event (TP53 mutation) rarely encountered in the ovary or secondary Mullerian system. This dual pathway to HGSCs underscores the subtle nature of many serous cancer origins in the tube, explains contrasting clinico-pathologic presentations, and explains why, until recently, the fallopian tube was unappreciated as the principal origin of HGSCs. Moreover, it highlights additional challenges faced in preventing or intercepting HGSCs at a curable stage.

Evidence for lineage continuity between early serous proliferations (ESPs) in the Fallopian tube and disseminated high-grade serous carcinomas

The distal Fallopian tube is a site of origin for many 'ovarian' high-grade serous carcinomas (HGSCs) with intraepithelial carcinomas (STICs) that share identical TP53 mutations with metastatic tumors. TP53 mutation-positive early serous proliferations (ESPs) comprise a spectrum including p53 signatures and serous tubal intraepithelial lesions (STILs) and are not considered malignant; however, ESPs are often the only abnormality found in Fallopian tubes of women with metastatic HGSC. The purpose of this study was to determine if a relationship exists between isolated ESPs and concurrent metastatic HGSCs in the absence of STIC. Fallopian tubes from 32 HGSCs without a co-existing STIC/HGSC in the endosalpinx were exhaustively sectioned. The presence of either STIC/HGSC or ESP in the endosalpinx was documented and DNA from tissues containing ESPs, concurrent HGSC, and control epithelia were interrogated for TP53 mutations by targeted amplicon-based sequencing with average coverage reads >4000 across DNA replicate samples. Serial sectioning revealed a previously unrecognized STIC/HGSC in 3 of 32 (9.3%) and ESPs in 13 (40.6%). Twelve contained TP53 mutations. Nine (75%) shared identical TP53 mutations with concurrent HGSCs, four at high (≥ 5%) and five at low (< 5%) allele frequency. All control epithelia were TP53 mutation-negative. This study, for the first time, indicates lineage identity between ESPs in the distal tube and some metastatic HGSCs via a shared site-specific TP53 mutation. It supports a novel serous carcinogenic sequence in which an ESP could eventually culminate in a metastatic serous cancer via 'precursor escape' and would explain the apparent sudden onset of cancers without co-existing STICs. This paradigm for serous cancer development underscores the likelihood that multiple precursor types in the Fallopian tube contribute to serous cancer development with implications for the evolution, pathologic classification, and prevention of this lethal malignancy. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.