Patients with low nicotinamide N-methyltransferase expression benefit significantly from bevacizumab treatment in ovarian cancer.

BACKGROUND: The role of nicotinamide N-methyltransferase (NNMT) in ovarian cancer is still elusive. Our aim is to explore the expression of NNMT in ovarian cancer and to assess its association with patient prognosis and treatment response. METHODS: We first analyzed the differential expression of NNMT among fallopian tube epithelium, primary ovarian cancers, metastatic ovarian cancers, and recurrent ovarian cancers using Gene Expression Ominus (GEO) database (GSE10971, GSE30587, GSE44104 and TCGA datasets). Then, we assessed the association of NNMT expression with clinical and molecular parameters using CSIOVDB database and GSE28739 dataset. Next, we evaluate the association of NNMT expression with the prognosis of ovarian cancer patients in both GSE9891 dataset and TCGA dataset. Finally, GSE140082 dataset was used to explore the association of NNMT expression with bevacizumab response. RESULTS: NNMT expression was significantly elevated in lymphovascular space invasion (LVSI)-positive ovarian cancers compared with that in LVSI-negative ovarian cancers (TCGA dataset, P < 0.05), Moreover, increased expression of NNMT was associated with increased tumor stage, grade, and mesenchymal molecular subtype (CSIOVDB database). Survival analysis indicated that increased expression of NNMT was associated with a reduced OS in both GSE9891 dataset (HR: 2.28, 95%CI: 1.51-3.43, Log-rank P < 0.001) and TCGA dataset (HR: 1.55, 95%CI: 1.02-2.36, Log-rank P = 0.039). Multivariate analysis further confirmed the negative impact of NNMT expression on OS in ovarian cancer patients in those two datasets. Furthermore, the NNMT-related nomogram showed that NNMT shared a larger contribution to OS, compared with debulking status. More interestingly, bevacizumab conferred significant improvements in OS for patients with low NNMT expression (HR: 0.56, 95%CI: 0.31-0.99, Log-rank P = 0.049). In contrast, patients with high NNMT expression didn't benefit from bevacizumab treatment significantly (HR: 0.85, 95%CI: 0.48-1.49, Log-rank P = 0.561). NNMT expression was positively correlated with the expression of genes, LDHA and PGAM1, involved in Warburg effect. CONCLUSIONS: In conclusion, NNMT expression is associated with the aggressive behavior of ovarian cancer, correlates with a poor prognosis, and is predictive of sensitivity to bevacizumab treatment.

Ovarian Mixed Epithelial Carcinoma With Extensive Bilateral Fallopian Tubes Metastases by the Low-grade Serous Carcinoma Component Mimicking Serous Tubal Intraepithelial Carcinoma: Case Presentation and Literature Review.

Seromucinous carcinoma of the ovary was a newly defined category in the revised 2014 World Health Organization Classification of Tumors of Female Reproductive Organs. It was defined as a carcinoma composed of predominantly of serous and endocervical-type mucinous epithelium. Foci containing clear cells, and areas of endometrioid and squamous differentiation are not uncommon. It is a rare entity with morphologic and immunophenotypic features overlapping other types of ovarian carcinoma. There are different opinions as to whether it is a distinct entity or a histologic variant of well-established entities. Subsequent, to the writing of this manuscript the WHO 2020 reclassified this tumor as a type of endometrioid carcinoma. Here we present a case of seromucinous carcinoma of bilateral ovaries that had variable differentiation and morphology at different sites. Tumor in the fallopian tubes, ovarian surfaces, omentum, and peritoneal surfaces displayed predominant features of low-grade serous carcinoma, while the tumor in the ovaries had predominant mucinous carcinoma morphology with a confluent/expansile growth pattern. The mucosal involvement of the fallopian tubes morphologically mimicked serous tubal intraepithelial carcinoma.

Second Primary Ovarian Epithelial, Fallopian Tube, and Primary Peritoneal Cancers after Breast Cancer Diagnosis: Korea Central Cancer Registry.

PURPOSE: A prior history of breast cancer is a risk factor for the subsequent development of primary peritoneal, epithelial ovarian, and fallopian tubal (POFT) cancers. This study aimed to estimate the incidence of secondary POFT malignancy in breast cancer patients and the clinical outcomes of primary and secondary POFT cancer. MATERIALS AND METHODS: We searched the Korea Central Cancer Registry to find patients with primary and secondary POFT cancer who had breast cancer in 1999-2017. The incidence rate and standardized incidence ratio were calculated. Additionally, we compared the overall survival of patients with primary and secondary POFT cancer. RESULTS: Based on the age-standardized rate, the incidence of second primary POFT cancer after breast cancer was 0.0763 per 100,000 women, which increased in Korea between 1999 and 2017. Among the 30,366 POFT cancer patients, 25,721 were primary POFT cancer only, and 493 had secondary POFT cancer after a breast cancer diagnosis. Second primary POFT cancer patients were older at the time of diagnosis (55 vs. 53, p < 0.001) and had a larger proportion of serous histology (68.4% vs. 51.2%, p < 0.001) than patients with primary POFT. There were no differences between the two groups in tumor stage at diagnosis. The 5-year overall survival rates were 60.2% and 56.3% for primary and secondary POFT cancer, respectively (p=0.216). CONCLUSION: The incidence of second primary POFT cancer after breast cancer increased in Korea between 1999 and 2017. Besides, second primary POFT cancer patients were diagnosed at older ages and had more serous histology.

Serous Tubal Intraepithelial Carcinoma-Like and Pagetoid Tubal Metastasis of an Ovarian Large Cell Neuroendocrine Carcinoma: Peculiar Metastatic Growth Patterns of a Rare Tumor.

A large cell neuroendocrine carcinoma of the ovary is presented because of tubal metastases with peculiar growth patterns: pagetoid and serous tubal intraepithelial carcinoma-like. The possibility that a tubal intraepithelial carcinoma could represent a metastasis should be considered by pathologists.

Transtubal Spread of a Superficially Invasive Cervical Adenocarcinoma to the Ovaries After 11 Years.

We report a 55-yr-old woman who presented with bilateral ovarian masses, 11 yr after hysterectomy for superficially invasive stage IA1 cervical adenocarcinoma of usual (human papillomavirus-associated) type. The bilateral ovarian tumors were composed of glands lined by malignant mucinous epithelium and these tumors were metastases from her previous cervical adenocarcinoma, based on morphology, immunophenotype, and positive in situ hybridization for human papillomavirus. In addition, there was extensive involvement of the mucosa of the left fallopian tube by malignant mucinous epithelium. The patient is alive and well 2 yr after the ovarian recurrence. The phenomenon of minimally invasive cervical adenocarcinoma metastasizing to the ovary has been described previously; the extrauterine disease is typically limited to the ovaries and associated with a relatively favorable prognosis. The presence of fallopian tube involvement by cervical adenocarcinoma has rarely been reported, and suggests transtubal spread of tumor. Unique to this case is the >11 yr interval between diagnosis of the cervical and ovarian disease, with previously described cases showing up to a 7 yr latency period. This case demonstrates that spread of cervical adenocarcinoma to the ovaries, via the fallopian tube lumen, can occur after a very long latent period and this possibility must be considered when examining adnexal mass(es) in women who have previously had a hysterectomy for cervical adenocarcinoma.

Fallopian Tube Neoplasia and Mimics.

This review discusses select fallopian tube entities and their associated mimics. It first focuses on adenomatoid tumors, the most common benign tumor of the fallopian tube. High-grade serous carcinoma and its precursor, serous tubal intraepithelial carcinoma, are then addressed. Finally, attention is turned to endometrioid proliferations of the fallopian tube. A diagnostic approach is provided for these lesions, with an emphasis on differential diagnoses and situations in which a benign lesion may appear malignant, and vice-versa.

[Malignant epithelial ovarian cancer: Role of intra peritoneal chemotherapy and hyperthermic intra peritoneal chemotherapy (HIPEC): Article drafted from the French Guidelines in oncology entitled "Initial management of patients with epithelial ovarian cancer" developed by FRANCOGYN, CNGOF, SFOG, GINECO-ARCAGY under the aegis of CNGOF and endorsed by INCa]. / Tumeurs épithéliales malignes de l'ovaire : place de la chimiothérapie intrapéritonéale et de la chimiothérapie hyperthermique intrapéritonéale (CHIP). Article rédigé sur la base de la recommandation nationale de bonnes pratiques cliniques en cancérologie intitulée « Conduites à tenir initiales devant des patientes atteintes d'un cancer épithélial de l'ovaire ¼ élaborée par FRANCOGYN, CNGOF, SFOG, GINECO-ARCAGY sous l'égide du CNGOF et labellisée par l'INCa.

Intraperitoneal drug delivery in first-line treatment of advanced ovarian cancer have been widely studied. After a complete primary surgery or with residual disease<1cm, intraperitoneal chemotherapy significantly improves disease-free and overall survival (NP1), but with more local and systemic toxicities. Whenever this therapeutic option is under consideration, the ratio efficacy/toxicity must be carefully discussed. Intraperitoneal chemotherapy has to be considered after complete or optimal primary surgery in ovarian, tubal or primitive peritoneal carcinomatosis FIGO IIIC. This treatment must be performed by trained teams and after an assessment of the ratio efficacy/toxicity. In one randomized study, hyperthermic intraperitoneal chemotherapy (HIPEC) using cisplatinum at interval surgery demonstrated an improvement in recurrence free and overall survival compared to surgery alone, in patients initially not resectable and with residual tumor less than 1cm (complete or optimal surgery) (NP1). HIPEC has to be considered after a complete or optimal interval surgery (residu<10mm) in patients with ovarian, tubal or primitive carcinomatosis FIGO IIIC, initially not resectable (Grade B).

Fallopian Tube Mucosal Involvement in Cervical Gastric-type Adenocarcinomas: Report of a Series With Discussion of the Distinction From Synchronous In Situ Tubal Lesions.

Cervical gastric-type adenocarcinomas are aggressive non-human papillomavirus-related carcinomas with a propensity for extracervical spread, including unusual sites such as the omentum, peritoneum, and ovary. We report 7 cases of cervical gastric-type adenocarcinoma with fallopian tube involvement predominantly in the form of mucosal colonization without underlying invasion. As far as we are aware, this has not been previously described and this report adds to the literature regarding metastatic neoplasms, which may exhibit tubal mucosal involvement and mimic an in situ lesion at this site. In all cases, there was associated ovarian involvement and in 6 of 7 cases, there was endometrial colonization. We speculate that the fallopian tube (and ovarian) involvement is secondary to transuterine spread. Given the occasional occurrence of multifocal gastric-type glandular lesions (benign or malignant) involving different sites in the female genital tract, we discuss the distinction between synchronous independent and metastatic lesions.

Isolated fallopian tube metastasis from colorectal cancer: ultrasonographic features.

We present here the first-reported case of tubal metastasis from colorectal cancer diagnosed by a preoperative pelvic ultrasound. A 53-year-old woman suffering from vaginal discharge was referred to us 2 years after she underwent a partial colectomy for adenocarcinoma. The pelvic ultrasound examination revealed a right pelvic mass of 52 × 24 × 38 mm, independent of the right ovary, which was apparently unaffected. A right salpingo-oophorectomy was performed and the definitive histopathology examination showed a recurrence of the initial adenocarcinoma with a right tubal metastasis. The eventuality of such an unusual site of metastasis should be remembered.

Malignant Female Adnexal Tumor of Probable Wolffian Origin: Case Report and Literature Review.

Although most female adnexal tumors of probable Wolffian origin have a benign biologic behavior, occasional cases have exhibited malignant potential. We encountered a 50-yr-old woman with an uncommon female adnexal tumors of probable Wolffian origin, which involved bilateral ovaries, invaded the ipsilateral fallopian tube, and extended to the uterine serosa. The initial histopathologic presentation caused significant confusion in pathologic diagnosis. Multiple differential diagnoses including ovarian endometrioid carcinoma, Sertoli cell tumor, and metastasis from nongynecologic organs were considered. After careful examination of the histologic findings and a thorough investigation with multiple immunohistochemical stains, the diagnosis was ultimately established. A literature review on female adnexal tumors of probable Wolffian origin including a malignant form is presented.

Serous Tubal Intraepithelial Carcinoma or Not? Metastases to Fallopian Tube Mucosa Can Masquerade as In Situ Lesions.

CONTEXT: - Nonuterine high-grade serous carcinomas (HGSCs) are believed to arise most often from precursors in the fallopian tube referred to as serous tubal intraepithelial carcinomas (STICs). A designation of tubal origin has been suggested for all cases of nonuterine HGSC if a STIC is identified. OBJECTIVE: - To highlight that many different types of nongynecologic and gynecologic carcinomas, including HGSC, can metastasize to the tubal mucosa and mimic de novo STIC. DATA SOURCES: - A mini-review of several recently published studies that collectively examine STIC-like lesions of the fallopian tube. CONCLUSIONS: - The fallopian tube mucosa can be a site of metastasis from carcinomas arising elsewhere, and pathologists should exercise caution in diagnosing STIC without first considering the possibility of metastasis. Routinely used immunohistochemical stains can often be used to determine if a STIC-like lesion is tubal or nongynecologic in origin. In the context of uterine and nonuterine HGSC, STIC may represent a metastasis rather than the site of origin, particularly when widespread disease is present.

Clinicopathological characteristics of fallopian tube metastases from primary endometrial, cervical, and nongynecological malignancies: a single institutional experience.

This study was aimed at investigating the clinicopathological characteristics of tubal metastases originating from primary endometrial, cervical, and nongynecological malignancies. We performed a 4-year retrospective study in which fallopian tube tissues obtained from 60 patients with tubal metastases were examined. In addition, we compared the number of tubal metastasis cases detected during periods of representative or whole tubal sampling. Twenty-three and 37 tubal metastases were found in cases examined after representative and whole tubal sampling techniques, respectively. Four cases of microscopic tubal metastases were detected via whole sampling, whereas no microscopic lesions were identified via representative sampling. The metastatic lesions originated from 14 uterine (10, endometrium; 4, cervix) and 46 nongynecological tumors (21, colon; 15, stomach; 5, biliary; 3, appendix; 2, breast). Tumors were most commonly involved in the muscle and lamina propria (n = 17). We noted distinctive histopathological features according to the extent of mural involvement: fibromyxoid stromal reaction and lymphohistiocytic infiltration in tumors involving the muscle and subepithelial connective tissue, architectural alterations of plicae in those involving the subepithelial connective tissue, and intraluminal mucinous and inflammatory exudate adjacent to intraepithelial tumors. We observed distinctive histopathological features associated with tubal metastases according to the extent of mural involvement. In addition, we demonstrated that the sampling method used in the routine microscopic examination of the fallopian tube affects the detection of tubal metastases. Our data support the notion that it is more logical to thoroughly sample both the fimbrial ends and the nonfimbriated portions of fallopian tubes for all salpingectomy specimens in the setting of cancer surgery.

The expression of asparaginyl endopeptidase promotes growth potential in epithelial ovarian cancer.

Epithelial ovarian cancer (EOC) is the most common and lethal cancer-related death among females in the world. Asparaginyl endopeptidase (AEP) is a member of C13 family peptidases and expressed in the extracellular matrix and tumor cells. The aim of this article is to explore the function of asparaginyl endopeptidase in epithelial ovarian cancer. The expression of AEP was examined in 20 EOC samples, 3 EOC metastasis samples, 6 fallopian tube metastasis samples, 4 peritoneum metastasis samples and 20 benign ovarian tumor samples by immunohistochemistry. The expression of AEP was also evaluated in serum and ascites of EOC patients by elisa. And we used a lentiviral vector to overexpress AEP in human epithelial ovarian cancer cell lines SKOV3ip and detected the function of AEP-SKOV3ip cells both in vitro and in vivo. The growth of AEP-SKOV3ip cells was observed by MTT, migration and tube formation assays in vitro. Additionally, the subcutaneous mice model was used to identify the tumor growth and metastasis in vivo. Mice tumors were stained for CD31 to determine the microvessel density (MVD). We demonstrated that AEP was highly expressed in the EOC patient tissues and ascites. The AEP transfected SKOV3ip cells could both promote tumor growth in vitro and in vivo. The MVD in AEP-SKOV3ip group was higher than that in NC-SKOV3ip group. Therefore, our results demonstrated that AEP could induce EOC growth and progressionboth in vitro and in vivo.

Uterine Serous Carcinomas Frequently Metastasize to the Fallopian Tube and Can Mimic Serous Tubal Intraepithelial Carcinoma.

We investigated the frequency, histopathologic, and immunohistochemical characteristics of tubal involvement in uterine serous carcinoma (USC) and aimed to clarify the relationship between "serous tubal intraepithelial carcinoma (STIC)" and USC in these cases. Cases of USC with complete tubal examination were prospectively collected and reviewed for the presence of tubal involvement. Immunohistochemical analysis for p53 and WT1 was performed on the endometrial and tubal tumor in cases with tubal involvement. Of 161 USC cases (pure USC or a component of a mixed carcinoma or a carcinosarcoma), 32 (20%) showed tubal involvement (unilateral: n=19; bilateral: n=13). The uterine tumors in cases with tubal involvement showed a trend toward increased likelihood of deep myometrial and lymphovascular invasion (LVI) compared with those without tubal involvement. The tubal fimbriae were involved in 15/32 cases. Tubal involvement was mucosal in 30/32 cases, mural in 14/32, serosal in 5/32, invasive in 22/32, and there was LVI in the tube in 13/32. STIC-like features were seen in 17/32 cases (7 as the only pattern of involvement, 9 with associated invasive carcinoma, and 5 with LVI). Immunostaining showed complete concordance of p53 and WT1 between the endometrial and tubal tumors in 26/32 cases, the majority being WT1 negative or only focally positive (19/26), and all exhibiting mutation-type p53 staining. On the basis of the histologic and immunohistochemical features, the tubal tumor was considered to represent metastatic USC in 26/32 cases, most likely metastatic USC in 2/32 cases, an independent tubal primary tumor in 3/32 cases, and to be of uncertain origin in the 1 remaining case. STIC-like lesions were considered to represent metastatic USC in 12/17 cases, most likely metastatic USC in 2/17 cases, an independent tubal primary in 2/17 cases, and of uncertain origin in the 1 remaining case. Tubal involvement, including STIC-like lesions, is seen in one fifth of USC when the tubes are examined in their entirety. The tubal involvement is metastatic in the vast majority of cases. Immunohistochemical studies assist, in most cases, in confirming the metastatic nature of the tubal disease. Consideration should be given to completely examining the fallopian tubes in apparent stage I or II USCs, as this will result in upstaging in a significant minority of cases.

Renal cell carcinoma metastatic to the ovary or fallopian tube: a clinicopathological study of 9 cases.

Renal cell carcinoma (RCC), the most common type of kidney cancer in adult, rarely metastasizes to the ovary or fallopian tube, and most cases published in the literature were case reports. Herein, we describe the clinicopathological features of 9 cases of RCC metastatic to the ovary (n = 8) or the fallopian tube (n = 1). The patients' age at the onset of primary renal tumor was available in 8 patients, ranging from 37 to 73 years (mean, 51 years; median, 50 years). Ovarian metastasis was detected prior to or concurrently with the primary renal tumors in 3 patients, and after the diagnosis of renal tumors in 6 patients. The histotypes of the RCCs were clear cell (n = 7), chromophobe (n = 1), and unclassified (n = 1). Immunohistochemical stainings were performed on the sections containing metastatic tumors in 4 cases. Interestingly, pagetoid intraepithelial spread in the tubal mucosa was observed in the case of RCC metastatic to the fallopian tube. Among the 8 patients with follow-up data, 5 died of disease and 3 were alive with disease, with a follow-up period ranging from 3.7 months to 17 years (mean, 77 months; median, 53 months) after the diagnosis of primary kidney tumors. Diagnostically, metastatic RCC may mimic primary ovarian tumors clinically, morphologically, or immunophenotypically. Pathologists should also keep in mind that both ovarian and kidney tumors express PAX8 and PAX2, the markers commonly used to diagnose metastatic RCC. In addition, chromophobe RCC only rarely metastasizes, but it can be a diagnostic challenge when it metastasizes to the ovary.

Next-Generation Sequencing of Tubal Intraepithelial Carcinomas.

IMPORTANCE: High-grade serous carcinoma (HGSC) is the most prevalent and lethal form of ovarian cancer. HGSCs frequently arise in the distal fallopian tubes rather than the ovary, developing from small precursor lesions called serous tubal intraepithelial carcinomas (TICs, or more specifically, STICs). While STICs have been reported to harbor TP53 mutations, detailed molecular characterizations of these lesions are lacking. OBSERVATIONS: We performed targeted next-generation sequencing (NGS) on formalin-fixed, paraffin-embedded tissue from 4 women, 2 with HGSC and 2 with uterine endometrioid carcinoma (UEC) who were diagnosed as having synchronous STICs. We detected concordant mutations in both HGSCs with synchronous STICs, including TP53 mutations as well as assumed germline BRCA1/2 alterations, confirming a clonal association between these lesions. Next-generation sequencing confirmed the presence of a STIC clonally unrelated to 1 case of UEC, and NGS of the other tubal lesion diagnosed as a STIC unexpectedly supported the lesion as a micrometastasis from the associated UEC. CONCLUSIONS AND RELEVANCE: We demonstrate that targeted NGS can identify genetic alterations in minute lesions, such as TICs, and confirm TP53 mutations as early driving events for HGSC. Next-generation sequencing also demonstrated unexpected associations between presumed STICs and synchronous carcinomas, providing evidence that some TICs are actually metastases rather than HGSC precursors.

Secondary Involvement of the Adnexa and Uterine Corpus by Carcinomas of the Uterine Cervix: A Detailed Morphologic Description.

Cervical carcinoma infrequently involves the uterine corpus or adnexa. Metastatic adenocarcinoma (AC) to the ovaries can be difficult to distinguish from primary ovarian tumors, and metastatic squamous cell carcinoma (SCC) to these sites has not been well described. Our aim was to provide a detailed description of the morphologic patterns of adnexal and corpus involvement by cervical carcinoma. Cases were identified over a 15-yr period and the following features were recorded: visible lesion, depth of invasion, lymphovascular invasion, and patterns of spread. Only usual human papillomavirus-associated tumors were included. Twenty cases with available slides were identified (2 in situ and 8 invasive SCC; 10 AC); 17 had visible lesions, usually with deep cervical and lymphovascular invasion. Sixteen involved the corpus (1 in situ, 7 SCC, 8 AC), all colonizing endometrium and 10 invading myometrium. SCC involved the ovary and fallopian tube in 4 and 6 cases, respectively, whereas AC involved the ovary in 4 (2 unilateral, 2 bilateral) and the tube in 8 cases. SCC in the ovary usually showed parenchymal invasion, and parenchymal and mucosal involvement in the tube. AC in the ovary ranged from small nodules to confluent expansile growth, whereas in the tube it often showed mucosal colonization mimicking a primary tubal process. Adnexal metastasis of cervical carcinoma is rare and usually coexists with endometrial and myometrial extension from the cervix. Both squamous and ACs can colonize tubal and endometrial mucosa; AC in particular can mimic primaries at those sites. Bilaterality is not a common feature of metastatic endocervical AC.

Microscopic Omental Metastasis in Clinical Stage I Endometrial Cancer: A Meta-analysis.

BACKGROUND: A patient with early-stage endometrial cancer may possibly have microscopic metastasis in the omentum, which is associated with a poor prognosis. The purpose of this study was to identify risk factors for microscopic omental metastasis in patients with clinical stage I endometrial cancer to establish the indications for selective omentectomy. METHODS: We searched the PubMed, EMBASE, and Cochrane Library databases for published studies from inception to August 2014, using terms such as 'endometrial cancer' or 'uterine cancer' for disease, 'omentectomy' or 'omental biopsy' for intervention, and 'metastasis' for outcome. Two reviewers independently identified the studies that matched the selection criteria. We calculated the pooled risk ratios (RRs) with 95 % confidence intervals (CI) of each surgicopathologic finding for microscopic omental metastases in clinical stage I endometrial cancer. We also calculated the prevalence of microscopic omental metastases. RESULTS: Among 1163 patients from ten studies, 22 cases (1.9 %) of microscopic omental metastases were found, which accounted for 26.5 % of all omental metastases. Positive lymph nodes (RR 8.71, 95 % CI 1.38-54.95), adnexal metastases (RR 16.76, 95 % CI 2.60-107.97), and appendiceal implants (RR 161.67, 95 % CI 5.16-5061.03) were highly associated with microscopic omental metastases. CONCLUSIONS: Microscopic omental metastases were not negligible in patients with clinical stage I endometrial cancer. Those with a risk factor of microscopic omental metastases were recommended for selective omentectomy.

Nongynecologic metastases to fallopian tube mucosa: a potential mimic of tubal high-grade serous carcinoma and benign tubal mucinous metaplasia or nonmucinous hyperplasia.

Mucosal alterations of the fallopian tube are generally thought to represent alterations of the native tubal mucosal epithelium, whether benign or malignant. The current paradigm implicating the fallopian tube fimbriae as the origin of most pelvic high-grade serous carcinomas (HGSCs) is based on the premise that HGSC growing within the tubal mucosa originated there. This has fueled proposals to redefine classification rules for assigning the primary site of origin on the basis of the presence or absence of HGSC in the tubal mucosa. The corollary is that it is unlikely for metastatic carcinoma to grow within fallopian tube mucosa. Evidence to support or refute this corollary is minimal, in part because the fallopian tubes historically have been ignored. This study reports the pattern and topography of 100 nongynecologic cancers that metastasized to the fallopian tubes. Most tumors were adenocarcinoma (87%), and the remainder included lymphomas, neuroendocrine tumors, and mesotheliomas. The most common primary origins of tumor were the colon (35%) and breast (15%). Gross evidence of a tubal nodule or mass was only seen in 35% of cases. Ovarian metastases were present in 95% of cases, although 23% did not exhibit gross evidence of metastasis. Tumor involved the fimbriae in 49% of cases, including 10% of cases in which the tumor was restricted to the fimbriae without involving the nonfimbriated portion of the tube. The anatomic distribution of metastases included the tubal mucosa (29%), submucosa (43%), muscularis (54%), serosa (76%), lymphovascular spaces (38%), intraluminal space (16%), and mesonephric remnants (39%). The most common architectural pattern of mucosal growth was a flat layer (22/29 cases), followed by varying degrees of stratification, tufting, and papillary growth. High-grade atypia was present in 18/29 cases of mucosal growth, resulting in patterns that resembled primary tubal HGSC. Accompanying growth in the tubal submucosa frequently produced a pseudoinvasive pattern mimicking invasive tubal HGSC. Immunohistochemical expression of p53 by 8/18 high-grade mucosal metastases further contributed to the resemblance to primary tubal HGSC. Bland cytology was present in 11/29 cases of mucosal growth, some of which also exhibited mucinous features, resulting in patterns that resembled either tubal mucinous metaplasia or nonmucinous tubal hyperplasia. Although uncommon, it is possible for metastases of nongynecologic cancers to grow within the mucosa of the fallopian tube and create a potential diagnostic pitfall. Intramucosal growth of a tumor in the fallopian tube is not pathognomonic of a primary tubal origin of the tumor. These findings may carry implications for proposed criteria using the status of the fallopian tube mucosa to assign primary origin of a gynecologic cancer.