Uterine Inflammatory Myofibroblastic Tumors: Proposed Risk Stratification Model Using Integrated Clinicopathologic and Molecular Analysis.

Inflammatory myofibroblastic tumor (IMT) of the uterus is a rare mesenchymal tumor with largely benign behavior; however, a small subset demonstrate aggressive behavior. While clinicopathologic features have been previously associated with aggressive behavior, these reports are based on small series, and these features are imperfect predictors of clinical behavior. IMTs are most commonly driven by ALK fusions, with additional pathogenic molecular alterations being reported only in rare examples of extrauterine IMTs. In this study, a series of 11 uterine IMTs, 5 of which demonstrated aggressive behavior, were evaluated for clinicopathologic variables and additionally subjected to capture-based next-generation sequencing with or without whole-transcriptome RNA sequencing. In the 6 IMTs without aggressive behavior, ALK fusions were the sole pathogenic alteration. In contrast, all 5 aggressive IMTs harbored pathogenic molecular alterations and numerous copy number changes in addition to ALK fusions, with the majority of the additional alterations present in the primary tumors. We combined our series with cases previously reported in the literature and performed statistical analyses to propose a novel clinicopathologic risk stratification score assigning 1 point each for: age above 45 years, size≥5 cm,≥4 mitotic figures per 10 high-power field, and infiltrative borders. No tumors with 0 points had an aggressive outcome, while 21% of tumors with 1 to 2 points and all tumors with ≥3 points had aggressive outcomes. We propose a 2-step classification model that first uses the clinicopathologic risk stratification score to identify low-risk and high-risk tumors, and recommend molecular testing to further classify intermediate-risk tumors.

Cytoplasmic Pattern p53 Immunoexpression in Pelvic and Endometrial Carcinomas With TP53 Mutation Involving Nuclear Localization Domains: An Uncommon But Potential Diagnostic Pitfall With Clinical Implications.

A cytoplasmic pattern of p53 immunohistochemical expression has recently been reported in a rare subset of pelvic and endometrial cancers with a TP53 mutation involving domains affecting nuclear localization. This study reports the clinicopathologic features of 31 cases with a TP53 mutation involving nuclear localization, the largest study to date, emphasizing practical strategies for recognizing this uncommon variant and distinguishing it from the p53 wild-type pattern. The study also evaluates the prognostic significance of TP53 mutation involving nuclear localization in the ovarian high-grade serous carcinoma (HGSC) cohort of The Cancer Genome Atlas database. Most of the 31 tumors were advanced stage pelvic or endometrial HGSC. All TP53 mutations were predicted to result in loss of function. The p53 overexpression pattern was present in 6 tumors; the p53 null pattern in 3 and the p53 cytoplasmic pattern in 22 tumors. The p53 cytoplasmic pattern predominantly consisted of weak to moderate cytoplasmic staining in >95% of tumor cells as well as variable intensity nuclear staining involving a range of just a few cells to just under 80% of tumor cells. The p53 cytoplasmic pattern was observed in 100% of tumors with TP53 mutation in the nuclear localization domain and in 33% to 44% of tumors with a mutation in the adjacent tetramerization domain or nuclear exclusion sequence (P<0.01). p16 immunoexpression was present in 74% of tumors. In The Cancer Genome Atlas ovarian HGSC cohort, 9% of 471 nonredundant TP53-mutant cases had a nuclear localization domain, tetramerization domain, or nuclear exclusion sequence mutation but there was no significant difference in survival when compared to cases with TP53 mutation outside those domains (P>0.05). p53 cytoplasmic staining merits classification as an aberrant result despite coexisting nuclear staining that in some cases may resemble the p53 wild-type pattern. While positive p16 immunostaining may be of value to confirm diagnostically challenging cases of p53 cytoplasmic staining, a negative result is noninformative and molecular testing for TP53 mutation should be considered, if available.

Corded and Hyalinized Endometrioid Adenocarcinoma (CHEC) of the Uterine Corpus are Characterized by CTNNB1 Mutations and Can Show Adverse Clinical Outcomes.

Corded and hyalinized endometrioid adenocarcinoma (CHEC) is a morphologic variant of endometrioid adenocarcinoma that is typically low-grade [International Federation of Gynecology and Obstetrics (FIGO) grade 1-2]. CHEC exhibits a biphasic appearance with gland forming adenocarcinoma merging with a diffuse component with corded growth often in a hyalinized matrix; squamous differentiation is frequent and osteoid production can be seen. This morphologic appearance can invoke a large differential diagnosis including carcinosarcoma. CHEC is thought to be associated with good clinical outcome although the available data is sparse. We performed detailed clinical, morphologic, immunohistochemical, and molecular analyses on a cohort of 7 CHEC. Six cases exhibited features of classic low-grade CHEC while one case showed greater cytologic atypia (high-grade CHEC). Patient age ranged from 19 to 69 yr. Four patients presented at stage I, 2 at stage II, and 1 at stage III. All tumors demonstrated nuclear staining for beta-catenin and loss of E-cadherin in the corded and hyalinized component. There was relative loss of epithelial markers. Loss of PTEN and ARID1A was seen in 4 and 3 tumors, respectively, and 1 tumor displayed loss of MLH1 and PMS2. Next-generation sequencing revealed CTNNB1 and PI3K pathway mutations in all 7 cases with TP53 and RB1 alterations in the high-grade CHEC. Clinical follow-up was available for 6 patients; 2 died of disease (48 and 50 mo), 2 are alive with disease (both recurred at 13 mo), and 2 have no evidence of disease (13 and 77 mo). Our study shows that CHEC universally harbors CTNNB1 mutations with nuclear staining for beta-catenin, can rarely show high-grade cytology, and can be associated with adverse clinical outcomes.

Multiregion exome sequencing of ovarian immature teratomas reveals 2N near-diploid genomes, paucity of somatic mutations, and extensive allelic imbalances shared across mature, immature, and disseminated components.

Immature teratoma is a subtype of malignant germ cell tumor of the ovary that occurs most commonly in the first three decades of life, frequently with bilateral ovarian disease. Despite being the second most common malignant germ cell tumor of the ovary, little is known about its genetic underpinnings. Here we performed multiregion whole-exome sequencing to interrogate the genetic zygosity, clonal relationship, DNA copy number, and mutational status of 52 pathologically distinct tumor components from ten females with ovarian immature teratomas, with bilateral tumors present in five cases and peritoneal dissemination in seven cases. We found that ovarian immature teratomas are genetically characterized by 2N near-diploid genomes with extensive loss of heterozygosity and an absence of genes harboring recurrent somatic mutations or known oncogenic variants. All components within a single ovarian tumor (immature teratoma, mature teratoma with different histologic patterns of differentiation, and yolk sac tumor) were found to harbor an identical pattern of loss of heterozygosity across the genome, indicating a shared clonal origin. In contrast, the four analyzed bilateral teratomas showed distinct patterns of zygosity changes in the right versus left sided tumors, indicating independent clonal origins. All disseminated teratoma components within the peritoneum (including gliomatosis peritonei) shared a clonal pattern of loss of heterozygosity with either the right or left primary ovarian tumor. The observed genomic loss of heterozygosity patterns indicate that diverse meiotic errors contribute to the formation of ovarian immature teratomas, with 11 out of the 15 genetically distinct clones determined to result from nondisjunction errors during meiosis I or II. Overall, these findings suggest that copy-neutral loss of heterozygosity resulting from meiotic abnormalities may be sufficient to generate ovarian immature teratomas from germ cells.

Detailed Morphologic and Immunohistochemical Characterization of Myomectomy and Hysterectomy Specimens From Women With Hereditary Leiomyomatosis and Renal Cell Carcinoma Syndrome (HLRCC).

Hereditary leiomyomatosis and renal cell carcinoma syndrome (HLRCC), caused by a germline mutation in the fumarate hydratase (FH) gene, predisposes patients to uterine and cutaneous smooth muscle tumors and an aggressive type of renal cell carcinoma. Almost all women with HLRCC develop symptomatic uterine leiomyomas resulting in surgery at young ages, presenting an ideal opportunity for early detection of these patients and the implementation of surveillance measures for renal cell carcinoma. FH-deficient uterine leiomyomas can show characteristic morphologic features (FH-d morphology) that have been previously described. Immunohistochemistry (IHC) for FH can also be helpful in detecting FH deficiency in leiomyomas, which manifests as complete loss of staining for FH. However, the distribution and topography of FH-d morphology and FH loss by IHC in the context of multiple leiomyomas in patients with HLRCC has not been evaluated. The aim of this study is to describe in detail the clinical and pathologic characteristics of uterine leiomyomas from women with HLRCC. Six patients with proven FH germline mutations were included. All available slides were reviewed and FH IHC staining was performed on multiple blocks when possible. Clinical data were extracted from online medical records. All 6 patients presented with symptomatic uterine fibroids and underwent myomectomy (age 24 to 36 y), followed by hysterectomy in 2 patients (age 31 and 40 y). Specimens showed conventional leiomyomas, cellular leiomyomas and leiomyomas with bizarre nuclei. FH-d morphology was present in leiomyomas from all patients and was typically observed as a diffuse finding in the majority of slides across different leiomyoma types. FH-d morphology was absent in some leiomyoma sections from one patient and the morphologic features were focal and subtle in leiomyomas from 2 patients. Both hysterectomy specimens were also notable for showing scattered irregular tongues and nodules of smooth muscle proliferation (leiomyomatosis-like) in the background myometrium. Immunohistochemical staining of multiple slides per patient for FH showed either retained staining in all sections (2/6 cases), loss of staining in all sections (1 case) or variable staining across different leiomyomas (3 cases). In conclusion, patients with HLRCC undergo surgery at young ages for highly symptomatic uterine leiomyomas. FH-d morphology is usually a diffuse and well developed finding across different leiomyomas but may be absent or focal and subtle. FH IHC can show variable results and presence of retained FH staining should not be used to exclude the possibility of HLRCC. Referral for genetic counselling and testing should be considered in a young patient with uterine leiomyomas showing FH-d morphology even if immunohistochemical staining for FH is retained.

Prospective Detection of Germline Mutation of Fumarate Hydratase in Women With Uterine Smooth Muscle Tumors Using Pathology-based Screening to Trigger Genetic Counseling for Hereditary Leiomyomatosis Renal Cell Carcinoma Syndrome: A 5-Year Single Institutional Experience.

Pathology-based screening of uterine smooth muscle tumors (uSMT) for morphology suggestive of fumarate hydratase deficiency (FH-d morphology) has been proposed as a method to identify women at increased risk for hereditary leiomyomatosis renal cell carcinoma (HLRCC) syndrome. For 5 years our clinical diagnostic practice has evaluated all women with any type of uSMT for FH-d morphology (defined, at low magnification, as staghorn shaped blood vessels and alveolar pattern edema and, at high magnification, as tumor macronucleoli surrounded by a halo and cytoplasmic eosinophilic globules) and, when present, used the pathology report to advise genetic counseling to further evaluate for HLRCC syndrome. We now report the results of this prospective screening strategy, with emphasis on the incidence and clinicopathologic features of FH-d morphology in uSMT, the rate of patient uptake of referral to genetic counseling, and the results of genetic testing for FH germline mutation. Among 2060 women with a uSMT, FH-d morphology was reported in 1.4% (30 women). Ten women elected to undergo FH genetic testing and 6 of 10 (60%) had a FH germline mutation: 5 were pathogenic mutations and 1 was a mutation variant of unknown significance. Therefore, the screening program led to a confirmed genetic diagnosis of HLRCC syndrome in 0.24% of all women with any type of uSMT. The women with a pathogenic mutation were ages 24 to 40 years. Although the majority of leiomyoma with bizarre nuclei exhibited FH-d morphology, the uSMT were conventional leiomyomas with FH-d morphology in 2 of 5 women found to have a pathogenic FH germline mutation. Relying on an abnormal FH immunostain result to trigger genetic counseling referral would have resulted in 2 of 5 (40%) cases with pathogenic FH germline mutation but normal FH immunoexpression going undetected, both of which were missense type mutations. There was no difference in the incidence of pathogenic FH germline mutation between FH-d morphology uSMT with an abnormal versus a normal FH immunostain result. Overall, this study demonstrates that prospective morphology-based screening, integrated with referral for genetic counseling, can result in the diagnosis of HLRCC syndrome in otherwise unselected women with uSMT. We conclude that this strategy should be incorporated in the routine pathologic examination of all uterine smooth muscle tumors.

Well-differentiated papillary mesothelioma of the peritoneum is genetically defined by mutually exclusive mutations in TRAF7 and CDC42.

Well-differentiated papillary mesothelioma is an uncommon mesothelial neoplasm that most frequently arises in the peritoneal cavity of women of reproductive age. Whereas malignant mesothelioma is an aggressive tumor associated with poor outcome, well-differentiated papillary mesothelioma typically exhibits indolent behavior. However, histologically differentiating between these two entities can be challenging, necessitating the development of distinguishing biomarkers. While the genetic alterations that drive malignant mesothelioma have recently been determined, the molecular pathogenesis of well-differentiated papillary mesothelioma is unknown. Here we performed genomic profiling on a cohort of ten well-differentiated papillary mesothelioma of the peritoneum. We identified that all tumors harbored somatic missense mutations in either the TRAF7 or CDC42 genes, and lacked alterations involving BAP1, NF2, CDKN2A, DDX3X, SETD2, and ALK that are frequent in malignant mesothelioma. We recently identified that another mesothelial neoplasm, adenomatoid tumor of the genital tract, is genetically defined by somatic missense mutations in the TRAF7 gene, indicating a shared molecular pathogenesis between well-differentiated papillary mesothelioma and adenomatoid tumors. To the best of our knowledge, well-differentiated papillary mesothelioma is the first human tumor type found to harbor recurrent mutations in the CDC42 gene, which encodes a Rho family GTPase. Immunohistochemistry demonstrated intact BAP1 expression in all cases of well-differentiated papillary mesothelioma, indicating that this is a reliable marker for distinguishing well-differentiated papillary mesothelioma from malignant mesotheliomas that frequently display loss of expression. Additionally, all well-differentiated papillary mesothelioma demonstrated robust expression of L1 cell adhesion molecule (L1CAM), a marker of NF-kB pathway activation, similar to that observed in adenomatoid tumors. In contrast, we have previously shown that L1CAM staining is not observed in normal mesothelial cells and malignant mesotheliomas of the peritoneum. Together, these studies demonstrate that well-differentiated papillary mesothelioma is genetically defined by mutually exclusive mutations in TRAF7 and CDC42 that molecularly distinguish this entity from malignant mesothelioma.

Endometrial Carcinoma, Grossing and Processing Issues: Recommendations of the International Society of Gynecologic Pathologists.

Endometrial cancer is the most common gynecologic neoplasm in developed countries; however, updated universal guidelines are currently not available to handle specimens obtained during the surgical treatment of patients affected by this disease. This article presents recommendations on how to gross and submit sections for microscopic examination of hysterectomy specimens and other tissues removed during the surgical management of endometrial cancer such as salpingo-oophorectomy, omentectomy, and lymph node dissection-including sentinel lymph nodes. In addition, the intraoperative assessment of some of these specimens is addressed. These recommendations are based on a review of the literature, grossing manuals from various institutions, and a collaborative effort by a subgroup of the Endometrial Cancer Task Force of the International Society of Gynecological Pathologists. The aim of these recommendations is to standardize the processing of endometrial cancer specimens which is vital for adequate pathological reporting and will ultimately improve our understanding of this disease.

Pathologic Prognostic Factors in Endometrial Carcinoma (Other Than Tumor Type and Grade).

Although endometrial carcinoma (EC) is generally considered to have a good prognosis, over 20% of women with EC die of their disease, with a projected increase in both incidence and mortality over the next few decades. The aim of accurate prognostication is to ensure that patients receive optimal treatment and are neither overtreated nor undertreated, thereby improving patient outcomes overall. Patients with EC can be categorized into prognostic risk groups based on clinicopathologic findings. Other than tumor type and grade, groupings and recommended management algorithms may take into account age, body mass index, stage, and presence of lymphovascular space invasion. The molecular classification of EC that has emerged from the Cancer Genome Atlas (TCGA) study provides additional, potentially superior, prognostic information to traditional histologic typing and grading. This classifier does not, however, replace clinicopathologic risk assessment based on parameters other than histotype and grade. It is envisaged that molecular and clinicopathologic prognostic grouping systems will work better together than either alone. Thus, while tumor typing and grading may be superseded by a classification based on underlying genomic abnormalities, accurate assessment of other pathologic parameters will continue to be key to patient management. These include those factors related to staging, such as depth of myometrial invasion, cervical, vaginal, serosal surface, adnexal and parametrial invasion, and those independent of stage such as lymphovascular space invasion. Other prognostic parameters will also be discussed. These recommendations were developed from the International Society of Gynecological Pathologists Endometrial Carcinoma project.

Inflammatory Myofibroblastic Tumor Associated With the Placenta: Short Tandem Repeat Genotyping Confirms Uterine Site of Origin.

Inflammatory myofibroblastic tumor (IMT) is a neoplasm of intermediate malignant potential that only rarely involves the gynecologic tract. Several cases of IMT arising in various locations including the lung, bladder, trachea, and breast in association with pregnancy have been reported in the literature, and 3 cases involving the placenta have been previously described. We report 2 cases of IMT identified in association with pregnancy; the first was an intrauterine mass delivered entirely separate from the placenta and fetus, and the second was an incidental mass identified within the placental parenchyma following delivery. Short tandem repeat genotyping was used to compare tissue from the tumor and the placenta for both cases. Both tumors were determined to be of maternal origin, confirming that uterine IMTs may present within the placenta or as a separate mass following delivery. This demonstrates the utility of short tandem repeat genotyping in determining the origin of tumors presenting in association with the placenta.

Mucosal Proliferations in Completely Examined Fallopian Tubes Accompanying Ovarian Low-grade Serous Tumors: Neoplastic Precursor Lesions or Normal Variants of Benign Mucosa?

Malignant transformation of the fallopian tube mucosa, followed by exfoliation of malignant cells onto ovarian and/or peritoneal surfaces, has been implicated as the origin of most pelvic high-grade serous carcinoma. Whether a parallel pathway exists for pelvic low-grade serous tumors [ovarian serous borderline tumor (SBT) and low-grade serous carcinoma (LGSC)] remains to be fully elucidated. The literature is challenging to interpret due to variation in the diagnostic criteria and terminology for cytologically low-grade proliferations of the fallopian tube mucosa, as well as variation in fallopian tube specimen sampling. Recently, a candidate fallopian tube precursor to ovarian SBT, so-called papillary tubal hyperplasia, was described in advanced stage patients. The current study was designed to identify fallopian tube mucosal proliferations unique to patients with low-grade serous ovarian tumors (serous cystadenoma, SBT, LGSC) and to determine if they may represent precursors to the ovarian tumors. Fallopian tubes were thinly sliced and entirely examined microscopically, including all of the fimbriated and nonfimbriated portions of the tubes, from patients with ovarian serous cystadenoma (35), SBT (61), and LGSC (11) and from a control population of patients with ovarian mucinous cystadenoma (28), mature cystic teratoma (18) or uterine leiomyoma (14). The slides of the fallopian tubes were examined in randomized order, without knowledge of the clinical history or findings in the ovaries or other organs. Alterations of the mucosa of the fallopian tube were classified as type 1: nonpapillary proliferation of cytologically bland tubal epithelium exhibiting crowding, stratification, and/or tufting without papillary fibrovascular cores or as type 2: papillary alterations consisting of a fibrovascular core lined by a cytologically bland layer of tubal epithelium. A third abnormality, type 3, consisted of detached intraluminal papillae, buds, or nests of epithelium that cytologically resembled the epithelial component of SBT or LGSC. Mucosal proliferations were identified in subsets of all populations, including the control populations. Overall, type 1 proliferations were in 28% to 61% of all patients and type 2 alterations in 4% to 16%. There was no statistically significant difference in the incidence of type 1 or type 2 proliferations between the class of ovarian serous tumors (benign, SBT, LGSC), between early and advanced stage SBT, or between patients with any ovarian serous tumor and the control population of nonserous diagnoses. Type 3 alterations were only identified in patients with advanced stage SBT/LGSC and not in any early stage SBT or cystadenoma. These findings suggest that type 3 alterations floating in the fallopian tube lumen represent exfoliation of tumor cells from ovarian and/or peritoneal origin. Our study did not identify a mucosal-based proliferation of the fallopian tubes that was specific to ovarian low-grade serous tumors. Cytologically bland mucosal proliferations appear to be common in fallopian tubes from patients of all ages and unrelated to ovarian tumorigenesis. A consensus on diagnostic criteria and terminology for these types of proliferations is needed, as well as further study into their etiology, including possible association with hormonal environment.

Adenomatoid tumors of the male and female genital tract are defined by TRAF7 mutations that drive aberrant NF-kB pathway activation.

Adenomatoid tumors are the most common neoplasm of the epididymis, and histologically similar adenomatoid tumors also commonly arise in the uterus and fallopian tube. To investigate the molecular pathogenesis of these tumors, we performed genomic profiling on a cohort of 31 adenomatoid tumors of the male and female genital tracts. We identified that all tumors harbored somatic missense mutations in the TRAF7 gene, which encodes an E3 ubiquitin ligase belonging to the family of tumor necrosis factor receptor-associated factors (TRAFs). These mutations all clustered into one of five recurrent hotspots within the WD40 repeat domains at the C-terminus of the protein. Functional studies in vitro revealed that expression of mutant but not wild-type TRAF7 led to increased phosphorylation of nuclear factor-kappa B (NF-kB) and increased expression of L1 cell adhesion molecule (L1CAM), a marker of NF-kB pathway activation. Immunohistochemistry demonstrated robust L1CAM expression in adenomatoid tumors that was absent in normal mesothelial cells, malignant peritoneal mesotheliomas and multilocular peritoneal inclusion cysts. Together, these studies demonstrate that adenomatoid tumors of the male and female genital tract are genetically defined by TRAF7 mutation that drives aberrant NF-kB pathway activation.

Genomic profiling of breast secretory carcinomas reveals distinct genetics from other breast cancers and similarity to mammary analog secretory carcinomas.

Secretory carcinomas of the breast are rare tumors with distinct histologic features, recurrent t(12;15)(p13;q25) translocation resulting in ETV6-NTRK3 gene fusion and indolent clinical behavior. Mammary analog secretory carcinomas arising in other sites are histopathologically similar to the breast tumors and also harbor ETV6-NTRK3 fusions. Breast secretory carcinomas are often triple (estrogen and progesterone receptor, HER2) negative with a basal-like immunophenotype. However, genomic studies are lacking, and whether these tumors share genetic features with other basal and/or triple negative breast cancers is unknown. Aside from shared ETV6-NTRK3 fusions, the genetic relatedness of secretory carcinomas arising in different sites is also uncertain. We immunoprofiled and sequenced 510 cancer-related genes in nine breast secretory carcinomas and six salivary gland mammary analog secretory carcinomas. Immunoprofiles of breast and salivary gland secretory carcinomas were similar. All the tumors showed strong diffuse MUC4 expression (n=15), and SOX10 was positive in all nine breast and in five out of six salivary gland tumors. All breast secretory carcinomas were triple negative or weakly ER-positive, and all tumors at both the sites expressed CK5/6 and/or EGFR, consistent with a basal-like phenotype. Sequencing revealed classic ETV6-NTRK3 fusion genes in all cases, including in carcinoma in situ of one breast tumor. Translocations were reciprocal and balanced in six out of nine breast and three out of six salivary gland tumors and were complex in three others. In contrast to most breast basal carcinomas, the mutational burden of secretory carcinomas was very low, and no additional pathogenic aberrations were identified in genes typically mutated in breast cancer. Five (56%) breast and two (33%) salivary gland tumors had simple genomes without copy number changes; the remainder had very few changes, averaging 1.3 per tumor. The ETV6-NTRK3 derivative chromosome was duplicated in one breast and one salivary gland tumor, and was the only copy number change in the latter. The findings highlight breast secretory carcinoma as a subtype more closely related to mammary analog secretory carcinoma than to basal/triple negative breast cancers of no special type. Lack of pathogenic mutations in common cancer-related genes suggests that ETV6-NTRK3 alone may suffice to drive these tumors and likely helps explain their indolent behavior.

FOXL2 Mutation Status in Granulosa Theca Cell Tumors of the Ovary.

Ovarian sex-cord stromal tumors that have between 10% and 50% granulosa cells in a prominent fibrothecomatous background have been referred to as granulosa theca cell tumors or mixed granulosa theca cell tumors. The classification and prognosis of these tumors is not clear. Most adult granulosa cell tumors of the ovary harbor a mutation in the FOXL2 gene, whereas fibromas and thecomas lack this mutation. The aim of our study was to assess the FOXL2 mutation status of ovarian granulosa theca cell tumors and to correlate the mutation status with morphologic and clinical characteristics. A FOXL2 mutation was detected in 6 of 12 (50%) granulosa theca cell tumors. Tumors with higher cellularity of granulosa cells were more likely to harbor a FOXL2 mutation as were tumors in which the granulosa cells formed large lobules. No conclusions could be drawn regarding the clinical and prognostic significance of the presence of a mutation given the small number of cases and limited clinical follow-up. Our study shows that half of granulosa theca cell tumors harbor the same FOXL2 mutation that characterizes adult granulosa cell tumors but there is no outcome evidence to guide whether mutation status should alter the classification of the tumor or the management of the patient.

Interobserver Reproducibility Among Gynecologic Pathologists in Diagnosing Heterologous Osteosarcomatous Component in Gynecologic Tract Carcinosarcomas.

Distinguishing hyalinized stroma from osteoid production by a heterologous osteosarcomatous component can be challenging in gynecologic tract carcinosarcomas. As heterologous components in a carcinosarcoma may have prognostic and therapeutic implications, it is important that these are recognized. This study examines interobserver reproducibility among gynecologic pathologists in the diagnosis of osteosarcomatous components, and its correlation with expression of the novel antibody SATB2 (marker of osteoblastic differentiation) in these osteosarcomatous foci. Digital H&E images from 20 gynecologic tract carcinosarcomas were reviewed by 22 gynecologic pathologists with a request to determine the presence or absence of an osteosarcomatous component. The 20 preselected cases included areas of classic heterologous osteosarcoma (malignant cells producing osteoid; n=10) and osteosarcoma mimics (malignant cells with admixed nonosteoid matrix; n=10). Interobserver agreement was evaluated and SATB2 scored on all 20 cases and compared with the original diagnoses. Moderate agreement (Fleiss' κ=0.483) was identified for the 22 raters scoring the 20 cases with a median sensitivity of 7/10 and a median specificity of 9/10 for the diagnosis of osteosarcoma. SATB2 showed 100% sensitivity (10/10) and 60% (6/10) specificity in discriminating classic osteosarcoma from osteosarcoma mimics. Utilizing negative SATB2 as a surrogate marker to exclude osteosarcoma, 73% (16/22) of the reviewers would have downgraded at least 1 case to not contain an osteosarcomatous component (range, 1-6 cases, median 1 case). Gynecologic pathologists demonstrate only a moderate level of agreement in the diagnosis of heterologous osteosarcoma based on morphologic grounds. In such instances, a negative SATB2 staining may assist in increasing accuracy in the diagnosis of an osteosarcomatous component.

Genomic profiling of malignant peritoneal mesothelioma reveals recurrent alterations in epigenetic regulatory genes BAP1, SETD2, and DDX3X.

Malignant mesothelioma is a rare cancer that arises from the mesothelial cells that line the pleural cavity and less commonly from the peritoneal lining of the abdomen and pelvis. Most pleural mesotheliomas arise in patients with a history of asbestos exposure, whereas the association of peritoneal mesotheliomas with exposure to asbestos and other potential carcinogens is less clear, suggesting that the genetic alterations that drive malignant peritoneal mesothelioma may be unique from those in pleural mesothelioma. Treatment options for all malignant mesotheliomas are currently limited, with no known targeted therapies available. To better understand the molecular pathogenesis of malignant peritoneal mesothelioma, we sequenced 510 cancer-related genes in 13 patients with malignant mesothelioma arising in the peritoneal cavity. The most frequent genetic alteration was biallelic inactivation of the BAP1 gene, which occurred in 9/13 cases, with an additional two cases demonstrating monoallelic loss of BAP1. All 11 of these cases demonstrated loss of BAP1 nuclear staining by immunohistochemistry, whereas two tumors without BAP1 alteration and all 42 cases of histologic mimics in peritoneum (8 multilocular peritoneal inclusion cyst, 6 well-differentiated papillary mesothelioma of the peritoneum, 16 adenomatoid tumor, and 12 low-grade serous carcinoma of the ovary) demonstrated intact BAP1 nuclear staining. Additional recurrently mutated genes in this cohort of malignant peritoneal mesotheliomas included NF2 (3/13), SETD2 (2/13), and DDX3X (2/13). While these genes are known to be recurrently mutated in pleural mesotheliomas, the frequencies are distinct in peritoneal mesotheliomas, with nearly 85% of peritoneal tumors harboring BAP1 alterations versus only 20-30% of pleural tumors. Together, these findings demonstrate the importance of epigenetic modifiers including BAP1, SETD2, and DDX3X in mesothelial tumorigenesis and suggest opportunities for targeted therapies.

Molecular Alterations of TP53 are a Defining Feature of Ovarian High-Grade Serous Carcinoma: A Rereview of Cases Lacking TP53 Mutations in The Cancer Genome Atlas Ovarian Study.

The Cancer Genome Atlas has reported that 96% of ovarian high-grade serous carcinomas (HGSCs) have TP53 somatic mutations suggesting that mutation of this gene is a defining feature of this neoplasm. In the current study, 5 gynecologic pathologists independently evaluated hematoxylin and eosin slides of 14 available cases from The Cancer Genome Atlas classified as HGSC that lacked a TP53 mutation. The histologic diagnoses rendered by these pathologists and the accompanying molecular genetic data are the subject of this report. Only 1 case (Case 5), which contained a homozygous deletion of TP53, had unanimous interobserver agreement for a diagnosis of pure HGSC. In 1 case (Case 3), all 5 observers (100%) rendered a diagnosis of HGSC; however, 3 observers (60%) noted that the histologic features were not classic for HGSC and suggested this case may have arisen from a low-grade serous carcinoma (arisen from an alternate pathway compared with the usual HGSC). In 2 cases (Cases 4 and 12), only 3 observers (60%) in each case, respectively, interpreted it as having a component of HGSC. In the remaining 10 (71%) of tumors (Cases 1, 2, 6-11, 13, and 14), the consensus diagnosis was not HGSC, with individual diagnoses including low-grade serous carcinoma, high-grade endometrioid carcinoma, HGSC, metastatic carcinoma, clear cell carcinoma, atypical proliferative (borderline) serous tumor, and adenocarcinoma, not otherwise specified. Therefore, 13 (93%) of the tumors (Cases 1-4 and 6-14) were either not a pure HGSC or represented a diagnosis other than HGSC, all with molecular results not characteristic of HGSC. Accordingly, our review of the TP53 wild-type HGSCs reported in The Cancer Genome Atlas suggests that 100% of de novo HGSCs contain TP53 somatic mutations or deletions, with the exception of the rare HGSCs that develop from a low-grade serous tumor precursor. We, therefore, propose that lack of molecular alterations of TP53 are essentially inconsistent with the diagnosis of ovarian HGSC and that tumors diagnosed as such should be rigorously reassessed to achieve correct classification.

Morphology and Immunohistochemistry for 2SC and FH Aid in Detection of Fumarate Hydratase Gene Aberrations in Uterine Leiomyomas From Young Patients.

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) syndrome is an autosomal dominant syndrome that results from mutations in the fumarate hydratase (FH) gene. Patients with HLRCC are at risk for smooth muscle tumors of the uterus and skin as well as renal tumors. The renal cell carcinomas associated with HLRCC are usually high stage at presentation, aggressive, and have poor clinical outcomes. Therefore these patients and family members would benefit from early identification and appropriate surveillance. In small studies, HLRCC-associated uterine leiomyomas have been noted to display characteristic morphologic features including eosinophilic cytoplasmic inclusions, prominent eosinophilic nucleoli, and perinucleolar halos. Limited data suggest that positive staining for 2-succinocysteine (2SC) and loss of staining for FH by immunohistochemistry (IHC) can help with identification of HLRCC. The aim of this study was to evaluate the ability of morphology and IHC for FH and 2SC to help identify HLRCC in young patients with uterine smooth muscle tumors. We identified 194 evaluable uterine leiomyomas from women less than 40 years of age. We found FH gene aberrations by mutation analysis in 5 cases, a 2.6% incidence. Of these 5 cases, 4 displayed the characteristic morphologic features outlined above, whereas 1 did not. All 5 tumors with FH gene abnormalities showed positive staining for 2SC, whereas no FH gene aberrations were found in the 2SC-negative cases. Loss of FH staining was seen in 2 of the 5 cases, 1 with frameshift mutation and the other with homozygous deletion, whereas the remaining 3 cases with missense FH gene mutations were FH positive. Our study shows that morphologic features can be helpful for detection of HLRCC in uterine leiomyomas, although they may not be present in every case. IHC for 2SC and FH can be helpful: presence of positive staining for 2SC is sensitive and specific for detection of FH gene aberrations, whereas loss of staining for FH is specific but not sufficiently sensitive, as cases with missense mutations in the FH gene can show retained staining.

Clinical Sequencing Contributes to a BRCA-Associated Cancer Rediagnosis That Guides an Effective Therapeutic Course.

Cancer is currently classified and treated using an approach based on tissue of origin. Ambiguous or incorrect diagnoses, however, are common and often go unnoticed. Clinical cancer sequencing can provide diagnostic precision, therapeutic direction, and hereditary cancer risk assessment. This report presents a patient with an initial diagnosis of metastatic pancreatic adenocarcinoma (PDA), a disease with a dismal prognosis. Tumor sequencing revealed genomic abnormalities inconsistent with PDA, instead suggesting serous ovarian cancer. This molecular rediagnosis was further refined by the identification of a BRCA2 truncating mutation in the tumor, subsequently confirmed to be a germline event. These findings prompted the initiation of platinum-based chemotherapy, which produced a life-altering response, and referral to genetic counseling for her offspring. These results suggest that clinical tumor sequencing can simultaneously clarify diagnoses, guide therapy, and inform familial risk, even in patients with end-stage metastatic disease, making the case for the development of specific strategies to deploy sequencing coupled with big data in oncology to improve clinical cancer management.