Jocelyne Arseneau

DICER1 Mutations in Familial Multinodular Goiter With and Without Ovarian Sertoli-Leydig Cell Tumors

CONTEXT Nontoxic multinodular goiter (MNG) is frequently observed in the general population, but little is known about the underlying genetic susceptibility to this disease. Familial cases of MNG have been reported, and published reports describe 5 families that also contain at least 1 individual with a Sertoli-Leydig cell tumor of the ovary (SLCT). Germline mutations in DICER1, a gene that codes for an RNase III endoribonuclease, have been identified in families affected by pleuropulmonary blastoma (PPB), some of whom include cases of MNG and gonadal tumors such as SLCTs. OBJECTIVE To determine whether familial MNG with or without SLCT in the absence of PPB was associated with mutations in DICER1. DESIGN, SETTING, AND PATIENTS From September 2009 to September 2010, we screened 53 individuals from 2 MNG and 3 MNG/SLCT families at McGill University for mutations in DICER1. We investigated blood lymphocytes and MNG and SLCT tissue from family members for loss of the wild-type DICER1 allele (loss of heterozygosity), DICER1 expression, and microRNA (miRNA) dysregulation. MAIN OUTCOME MEASURE Detection of germline DICER1 gene mutations in familial MNG with and without SLCT. RESULTS We identified and characterized germline DICER1 mutations in 37 individuals from 5 families. Two mutations were predicted to be protein truncating, 2 resulted in in-frame deletions, and 1 was a missense mutation. Molecular analysis of the 3 SLCTs showed no loss of heterozygosity of DICER1, and immunohistochemical analysis in 2 samples showed strong expression of DICER1 in Sertoli cells but weak staining of Leydig cells. miRNA profiling of RNA from lymphoblastoid cell lines from both affected and unaffected members of the familial MNG cases revealed miRNA perturbations in DICER1 mutation carriers. CONCLUSIONS DICER1 mutations are associated with both familial MNG and MNG with SLCT, independent of PPB. These germline DICER1 mutations are associated with dysregulation of miRNA expression patterns.

Germline and somatic SMARCA4 mutations characterize small cell carcinoma of the ovary, hypercalcemic type

Small cell carcinoma of the ovary, hypercalcemic type (SCCOHT) is the most common undifferentiated ovarian malignancy in women under 40 years of age. We sequenced the exomes of six individuals from three families with SCCOHT. After discovering segregating deleterious germline mutations in SMARCA4 in all three families, we tested DNA from a fourth affected family, which also carried a segregating SMARCA4 germline mutation. All the familial tumors sequenced harbored either a somatic mutation or loss of the wild-type allele. Immunohistochemical analysis of these cases and additional familial and non-familial cases showed loss of SMARCA4 (BRG1) protein in 38 of 40 tumors overall. Sequencing of cases with available DNA identified at least one germline or somatic deleterious SMARCA4 mutation in 30 of 32 cases. Additionally, the SCCOHT cell line BIN-67 had biallelic deleterious mutations in SMARCA4. Our findings identify alterations in SMARCA4 as the major cause of SCCOHT, which could lead to improvements in genetic counseling and new treatment approaches.

Extending the phenotypes associated with DICER1 mutations

DICER1 is crucial for embryogenesis and early development. Forty different heterozygous germline DICER1 mutations have been reported worldwide in 42 probands that developed as children or young adults, pleuropulmonary blastoma (PPB), cystic nephroma (CN), ovarian sex cord‐stromal tumors (especially Sertoli‐Leydig cell tumor [SLCT]), and/or multinodular goiter (MNG). We report DICER1 mutations in seven additional families that manifested uterine cervix embryonal rhabdomyosarcoma (cERMS, four cases) and primitive neuroectodermal tumor (cPNET, one case), Wilms tumor (WT, three cases), pulmonary sequestration (PS, one case), and juvenile intestinal polyp (one case). One carrier developed (age 25 years) a pleomorphic sarcoma of the thigh; another carrier had transposition of great arteries (TGA). These observations show that cERMS, cPNET, WT, PS, and juvenile polyps fall within the spectrum of DICER1‐related diseases. DICER1 appears to be the first gene implicated in the etiology of cERMS, cPNET, and PS. Young adulthood sarcomas and perhaps congenital malformations such as TGA may also be associated. 32:1381–1384, 2011. ©2011 Wiley Periodicals, Inc.

Diagnosis of ovarian carcinoma cell type is highly reproducible: a transcanadian study.

Reproducible diagnosis of ovarian carcinoma cell types is critical for cell type-specific treatment. The purpose of this study was to test the reproducibility of cell type diagnosis across Canada. Analysis of the interobserver reproducibility of histologic tumor type was performed among 6 pathologists after brief training in the use of modified World Health Organization criteria to classify ovarian carcinomas into 1 of 6 categories: high-grade serous, endometrioid, clear cell, mucinous, low-grade serous, and other. These 6 pathologists independently reviewed a test set of 40 ovarian carcinomas. A validation set of 88 consecutive ovarian carcinomas drawn from 5 centers was subject to local review by 1 of the 6 study pathologists, and central review by a single observer. Interobserver agreement was assessed through calculation of concordance and κ values for pair-wise comparison. For the test set, the paired concordance between pathologists in cell type diagnosis ranged from 85.0% to 97.5% (average 92.3%), and the κ values were 0.80 to 0.97 (average 0.89). Inclusion of immunostaining results did not significantly improve reproducibility (P=0.69). For the validation set, the concordance between original diagnosis and local review was 84% and between local review and central review was 94%. The κ values were 0.73 and 0.89, respectively. With a brief training exercise and the use of defined criteria for ovarian carcinoma subtyping, there is excellent interobserver reproducibility in diagnosis of cell type. This has implications for clinical trials of subtype-specific ovarian carcinoma treatments.

Ovarian stromal tumors containing lutein or Leydig cells (luteinized thecomas and stromal Leydig cell tumors)--a clinicopathological analysis of fifty cases.

Fifty ovarian stromal tumors that had a predominant pattern of fibroma or thecoma but also contained cells typical of steroid hormonesecreting cells are reported. Forty-six tumors were classified as luteinized thecomas because the steroid cells resembled lutein cells and lacked crystalloids of Reinke. Four were classified as stromal Leydig cell tumors because crystalloids were identified in the steroid cells. The luteinized thecomas occurred at an average age of 46 years and were associated with estrogenic manifestations in 50% and androgenic changes in 11% of the cases. In the remaining cases there was no clinical or pathological evidence of steroid hormone production at the time of diagnosis. Six patients, two of whom were virilized, were pregnant. Four tumors appeared malignant on histologic examination. One of these tumors was rapidly fatal, the outcome is unknown in a second case, the third patient is alive and well at 5 years, and the fourth tumor was diagnosed too recently for evaluation of its behavior. The stromal Leydig cell tumors occurred at an average age of 61 years and were associated with virilization in one case, endometrial hyperplasia in another case, and endometrial hyperplasia with carcinoma in a third case. The fourth tumor was unassociated with endocrine manifestations. Luteinized thecomas and stromal Leydig cell tumors are indistinguishable except for the presence of crystalloids of Reinke in the latter. In view of the prolonged search that is necessary to find these structures in some stromal Leydig cell tumors and their well-known absence in the majority of testicular Leydig cell tumors, it is reasonable to assume that an unknown proportion of tumors in the luteinized thecoma category are unrecognized stromal Leydig cell tumors.

Loop electrosurgical excision procedure for squamous intraepithelial lesions of the cervix: advantages and potential pitfalls

Objective To evaluate the advantages and pitfalls of the loop electrosurgical excision procedure as applied to the diagnosis and treatment of cervical cancer precursors. Methods Loop electrosurgical excision procedure using local anesthesia and colposcopic guidance was performed in an outpatient clinical setting in 1189 consecutive patients referred for colposcopy for an abnormal Papanicolaou smear during a period of 4 years. Results Of the 1189 patients, 915 (77%) were managed in one sitting with the “see and treat” approach, and in 274 patients endocervical curettage and cervical biopsies preceded loop electrosurgical excision procedure. One hundred nineteen (10%) patients were lost to follow-up. Twenty-one patients had either adenocarcinoma in situ (15) or microinvasive squamous cell carcinoma (six) in the loop electrosurgical excision procedure specimen, whereas the electroexcised specimens contained no lesional tissue in 166 (14%) patients. Cure (ie, disease-free at 6 months or longer) was observed in 92% of the 883 evaluable patients after a single treatment and 95% after a repeat loop electrosurgical excision procedure. High-grade squamous intraepithelial lesion was successfully treated with loop electrosurgical excision procedure in 287 (93%) of 309 patients. Complications, mainly intra-and postoperative bleeding, occurred in 7% of the patients. In most loop electrosurgical excision procedure-negative cases, the referral cytologic diagnosis or colposcopy and/or histology were false-positive on review, or the biopsies performed before loop electrosurgical excision procedure removed smaller areas of abnormal tissue. Conclusions Loop electrosurgical excision procedure using the see and treat approach should be limited to cytologically and colposcopically unequivocal intraepithelial lesions, and depth of excision should be controlled by colposcopy using loop electrodes of appropriate size. In doubtful cases, particularly in the young patient, disease should be ascertained by expert histology and colposcopy before definite therapy. Loop electroexcision represents an attractive means of diagnosing and treating cervical cancer precursors.

Reproducibility of histological cell type in high-grade endometrial carcinoma

Subclassification of endometrial carcinoma according to histological type shows variable interobserver agreement. The aim of this study was to assess specifically the interobserver agreement of histological type in high-grade endometrial carcinomas, recorded by gynecological pathologists from five academic centers across Canada. In a secondary aim, the agreement of consensus diagnosis with immunohistochemical marker combinations was assessed including six routine (TP53, CDKN2A (p16), ER, PGR, Ki67, and VIM) and six experimental immunohistochemical markers (PTEN, ARID1A, CTNNB1, IGF2BP3, HNF1B, and TFF3). The paired interobserver agreement ranged from κ 0.50 to 0.63 (median 0.58) and the intraobserver agreement from κ 0.49 to 0.67 (median 0.61). Consensus about histological type based on morphological assessment was reached in 72% of high-grade endometrial carcinomas. A seven-marker immunohistochemical panel differentiated FIGO grade 3 endometrioid from serous carcinoma with a 100% concordance rate compared with the consensus diagnosis. More practically, a three-marker panel including TP53, ER, and CDKN2A (p16) can aid in the differential diagnosis of FIGO grade 3 endometrioid from endometrial serous carcinoma. Our study demonstrates that the inter- and intraobserver reproducibility of histological type based on morphology alone are mostly moderate. Ancillary techniques such as immunohistochemical marker panels are likely needed to improve diagnostic reproducibility of histological types within high-grade endometrial carcinomas.

Tubular Krukenberg tumor A problem in histopathologic diagnosis

A review of a series of 70 Krukenberg tumors seen in consultation disclosed 13 cases with a predominant tubular pattern. Eleven of them had been diagnosed by the referring pathologist as a tumor in the sex cord-stromal category, usually a Sertoli-Leydig cell tumor; no diagnosis was proferred in the other two cases. Three factors contributed to the erroneous diagnoses: a prominent tubular pattern, luteinization of the stroma of the tumor in five cases, and associated virilization in two cases. Each tumor, however, contained typical signet-ring cells that were readily demonstrable with mucicarmine stains. In six cases the tumors were unilateral and in seven, bilateral. Ten patients died of their cancer from 2 to 21 months after the diagnosis had been made. In one case the ovarian tumors were not discovered until autopsy. Two patients are alive 7 and 9 months postoperatively. A primary tumor was found in the stomach in four cases and in the sigmoid colon and appendix in one each. No primary tumor was found in seven cases but an autopsy had been performed in only one of these. The diagnosis of Krukenberg tumor must always be considered in the differential diagnosis of an ovarian tumor with a tubular pattern even though endocrine manifestations are present.

NLRP7 in the spectrum of reproductive wastage: rare non-synonymous variants confer genetic susceptibility to recurrent reproductive wastage

Background NLRP7 mutations are responsible for recurrent molar pregnancies and associated reproductive wastage. To investigate the role of NLRP7 in sporadic moles and other forms of reproductive wastage, the authors sequenced this gene in a cohort of 135 patients with at least one hydatidiform mole or three spontaneous abortions; 115 of these were new patients. Methods/Results All mutations were reviewed and their number, nature and locations correlated with the reproductive outcomes of the patients and histopathology of their products of conception. The presence of NLRP7 mutations was demonstrated in two patients with recurrent spontaneous abortions, and some rare non-synonymous variants (NSVs), present in the general population, were found to be associated with recurrent reproductive wastage. These rare NSVs were shown to be associated with lower secretion of interleukin 1β and tumour necrosis factor and therefore to have functional consequences similar to those seen in cells from patients with NLRP7 mutations. The authors also attempted to elucidate the cause of stillbirths observed in 13% of the patients with NLRP7 mutations by examining available placentas of the stillborn babies and live births from patients with mutations or rare NSVs. A number of severe to mild placental abnormalities were found, all of which are known risk factors for perinatal morbidity. Conclusions The authors recommend close follow-up of patients with NLRP7 mutations and rare NSVs to prevent the death of the rare or reduced number of babies that reach term.

The histomorphology of Lynch syndrome-associated ovarian carcinomas: toward a subtype-specific screening strategy.

Women with Lynch syndrome (LS) are at increased risk for the development of epithelial ovarian cancer (OC). Analogous to previous studies on BRCA1/2 mutation carriers, there is evidence to suggest a histotype-specific association in LS-associated OCs (LS-OC). Whereas the diagnosis of high-grade serous carcinoma is an indication for BRCA1/2 germline testing, in contrast, there are no screening guidelines in place for triaging OC patients for LS testing based on histotype. We performed a centralized pathology review of tumor subtype on 20 germline mutation-confirmed LS-OCs, on the basis of morphologic assessment of hematoxylin and eosin–stained slides, with confirmation by immunohistochemistry when necessary. Results from mismatch-repair immunohistochemistry (MMR-IHC) and microsatellite instability (MSI) phenotype status were documented, and detailed pedigrees were analyzed to determine whether previously proposed clinical criteria would have selected these patients for genetic testing. Review of pathology revealed all LS-OCs to be either pure endometrioid carcinoma (14 cases), mixed carcinoma with an endometrioid component (4 cases), or clear cell carcinoma (2 cases). No high-grade or low-grade serous carcinomas or mucinous carcinomas of intestinal type were identified. Tumor-infiltrating lymphocytes were prominent (≥40 per 10 high-powered fields) in 2 cases only. With the exception of 1 case, all tumors tested for MMR-IHC or MSI had an MMR-deficient phenotype. Within this cohort, 50%, 55%, 65%, and 85% of patients would have been selected for genetic workup by Amsterdam II, revised Bethesda Guidelines, SGO 10% to 25%, and SGO 5% to 10% criteria, respectively, with <60% of index or sentinel cases detected by any of these schemas. To further support a subtype-driven screening strategy, MMR-IHC reflex testing was performed on all consecutive non-serous OCs diagnosed at 1 academic hospital over a 2-year period; MMR deficiency was identified in 10/48 (21%) cases, all with endometrioid or clear cell histology. We conclude that there is a strong association between endometrioid and clear cell ovarian carcinomas and hereditary predisposition due to MMR gene mutation. These findings have implications for the role of tumor subtype in screening patients with OC for further genetic testing and support reflex MMR-IHC and/or MSI testing for newly diagnosed cases of endometrioid or clear cell ovarian carcinoma.