Erythrasma of the Vulva: An Invisible Dermatosis.

Erythrasma is a prevalent superficial bacterial infection typically caused by Corynebacteria species and preferentially affecting intertriginous sites including axillary, interdigital, and inguinal skin folds. However, erythrasma of the vulva is uncommon, with only 2 cases previously reported. Although erythrasma can be diagnosed clinically using Woods lamp examination, it may not always be considered in the differential diagnosis for patients presenting with persistent vulvar pruritus. We report 12 cases of vulvar erythrasma identified by histopathology, with a review of clinical and histologic features. The mean patient age was 60.1 yr and the mean patient BMI was 30.5. Five of 12 patients presented with pruritic rash. The time from symptom onset to diagnosis was 9 mo in 1 case, >18 mo in 4 cases, and unknown in the remaining cases. The characteristic histologic features were compact orthokeratosis and mild perivascular chronic inflammation. In all 12 cases, Periodic Acid-Schiff-diastase (PAS-D) staining highlighted intracorneal filamentous rods which were not readily appreciable on H&E. After the diagnosis of erythrasma, 4 patients were treated with topical lincomycin, of whom 3 had clinical improvement in symptoms. One patient was treated with topical macrolide antibiotic and also reported improvement in symptoms. Consideration of erythrasma on the differential for patients presenting with vulvar rash and pruritus may shorten the time to diagnosis and treatment, minimize patient discomfort, and reduce the scope and cost of diagnostic testing.

BAP1 and Claudin-4, But Not MTAP, Reliably Distinguish Borderline and Low-grade Serous Ovarian Tumors From Peritoneal Mesothelioma.

Peritoneal mesothelioma (PM) and serous neoplasms can be difficult to differentiate, particularly in small biopsies. BRCA1-associated protein 1 (BAP1) is expressed in benign tissues, but over 50% of PMs demonstrate complete loss of nuclear expression. Claudin-4, a tight junction protein, is expressed in most epithelial tumors but not in mesotheliomas. Methylthioadenosine phosphorylase (MTAP) is frequently co-deleted with cyclin-dependent kinase inhibitor 2a in mesotheliomas. These markers have proven useful in separating mesothelioma from its mimics, particularly when tumors are pleural based. In the peritoneum, BAP1 loss has been rarely reported in high-grade serous carcinomas, but overall, these markers have been minimally evaluated in ovarian serous borderline tumors and low-grade serous carcinomas. Thus, we assessed the utility of BAP1, claudin-4, and MTAP in the differential diagnosis of PM and low-grade serous neoplasms. Eighteen PM (16 epithelioid, 1 biphasic, and 1 sarcomatous), 24 low-grade serous carcinomas, and 25 serous borderline tumors were stained for BAP1, claudin-4, and MTAP. Loss of BAP1 nuclear expression was observed in 12 (67%) PM (11 epithelioid, 1 biphasic) but was retained in all serous tumors. Claudin-4 was positive in all serous tumors and negative in all PM. Complete loss of cytoplasmic MTAP was noted in 3 (17%) PMs and 1 (4%) serous borderline tumor, while all low-grade serous carcinomas showed retained expression. BAP1 loss reliably distinguishes PM from serous tumors, although it lacks sensitivity. Claudin-4 is a reliable marker to exclude PM. MTAP loss may occur in both PM and serous tumors, and thus is not useful in distinguishing these entities.

HPV-independent, p53-wild-type vulvar intraepithelial neoplasia: a review of nomenclature and the journey to characterize verruciform and acanthotic precursor lesions of the vulva.

Vulvar squamous cell carcinomas and their precursors are currently classified by the World Health Organization based on their association with high-risk human papillomavirus (HPV). HPV independent lesions often harbor driver alterations in TP53, usually seen in the setting of chronic vulvar inflammation. However, a group of pre-invasive vulvar squamous lesions is independent from both HPV and mutant TP53. The lesions described within this category feature marked acanthosis, verruciform growth and altered squamous maturation, and over the last two decades several studies have added to their characterization. They have a documented association with verrucous carcinoma and conventional squamous cell carcinoma of the vulva, suggesting a precursor role. They also harbor recurrent genomic alterations in several oncogenes, mainly PIK3CA and HRAS, indicating a neoplastic nature. In this review, we provide a historical perspective and a comprehensive description of these lesions. We also offer an appraisal of the terminology used over the years, going from Vulvar Acanthosis with Altered Differentiation and Verruciform Lichen Simplex Chronicus to Differentiated Exophytic Vulvar Intraepithelial Lesion and Vulvar Aberrant Maturation, the latter term having been recently proposed by the International Society for the Study of Vulvovaginal Diseases. In line with the recognition of these lesions by the 2020 World Health Organization Classification of Tumours as a neoplastic precursor, we herein propose the term HPV-independent, p53-wild-type verruciform acanthotic Vulvar Intraepithelial Neoplasia (HPVi(p53wt) vaVIN), which better conveys not only the pathology but also the neoplastic nature and the biologic risk inherent to these uncommon and challenging lesions. We outline strict morphologic and immunohistochemical criteria for its diagnosis and distinction from mimickers. Immunohistochemistry for p16 and p53 should be performed routinely in the diagnostic work-up of these lesions, and the morphologic alternative term vaVIN should be reserved for instances in which p16/HPV/p53 status is unknown. We also discuss management considerations and the need to further explore precursors within and beyond the spectrum of verruciform acanthotic vulvar intraepithelial neoplasia.

Sclerosing stromal tumour: a clinicopathological study of 100 cases of a distinctive benign ovarian stromal tumour typically occurring in the young.

AIMS: Since the sclerosing stromal tumour (SST) of the ovary was first described in 1973, few studies have expanded upon its histological features or overlap with other tumours. We thus investigate these aspects based on our experience with 100 cases. METHODS AND RESULTS: The patients, 14 of whom were pregnant, ranged from 12 to 63 years (median = 26 years). Ten patients had hormonal manifestations (seven oestrogenic, three androgenic). Bilateral ovarian involvement was present in two cases. Size ranged from 1 to 23 cm (mean = 8.4 cm). Most tumours were solid and white with focal yellow areas; oedema with cystic degeneration (seen in 25 cases) resulted in eight being predominantly cystic. On microscopic examination, alternating cellular and paucicellular areas (pseudolobulation) were prominent in 94 cases but seen to a limited degree in the remaining neoplasms. Admixed spindled and luteinised cells were present in all tumours, but 13 demonstrated mainly spindled cells and 19 demonstrated mainly lutein cells; 14 of the latter were from pregnant patients. The stroma was typically oedematous or collagenous, but in 14 cases was prominently hyalinised and, in four, myxoid. Prominent vascularity was present in most cases. The mitotic rate ranged from 0 to 8/10 high-power fields (HPF), but most demonstrated <1/10 HPF. CONCLUSIONS: The differential diagnosis of SST is broad, including fibromas, thecomas, solitary fibrous tumours, pregnancy luteomas, myxomas, other ovarian sex cord-stromal tumours with sclerosis and, rarely, Krukenberg tumours. Strict adherence to the requirement of pseudolobulation, prominent (usually ectatic) vessels, and lutein cells and fibroblasts admixed in a jumbled manner, will distinguish the neoplasm from others in the differential.

Vulvar angiomyofibroblastoma is molecularly defined by recurrent MTG1-CYP2E1 fusions.

Angiomyofibroblastoma (AMF), a rare benign vulvovaginal mesenchymal tumour, poses a diagnostic challenge due to histologic and immunohistochemical overlap with other vulvar mesenchymal tumours. Recently, MTG1-CYP2E1 fusion transcripts were reported in 5/5 AMFs; no other genetic alterations have been described to date. Herein, we sought to investigate the frequency of the MTG1-CYP2E1 fusion and the presence of other potential genetic alterations in a cohort of AMFs (n = 7, patient age range: 28-49 years). Tumours demonstrated classic morphologic features including alternating hypo/hypercellular areas, capillary channels surrounded by epithelioid/spindled tumour cells, and variable amounts of mature adipose tissue. reverse transcription-polymerase chain reaction (RT-PCR) for MTG1-CYP2E1 fusion, performed in all seven cases, showed the fusion transcript in five of six cases (one case with technical failure). Two tumours, including the one lacking the fusion, were subjected to targeted next-generation sequencing (104 genes) and a sarcoma fusion assay (28 genes); the fusion negative AMF also underwent RNA sequencing. No additional mutations, copy number alterations, or fusion genes were identified with the assays employed. We conclude that the majority of AMFs harbour recurrent MTG1-CYP2E1 fusion transcripts and identification of this fusion may aid in the diagnosis.

Müllerian Mucinous Cystadenomas of the Ovary: A Report of 25 Cases of an Unheralded Benign Ovarian Neoplasm Often Associated With Endometriosis and a Brief Consideration of Neoplasms Arising From the Latter.

A subset of ovarian mucinous tumors demonstrates müllerian-type epithelium, with such lesions variably designated "endocervical-like" and seromucinous since their popularization based on a report of borderline examples in 1989. While müllerian mucinous borderline tumors and carcinomas have been highlighted in the literature, there has been minimal attention given to benign müllerian mucinous tumors, particularly müllerian mucinous cystadenomas. Given the paucity of literature describing the features of müllerian mucinous cystadenomas/cystadenofibromas, diagnostic difficulties may arise when papillary features are present and in cases that show a subtle transition from endometriosis. We thus reviewed 25 cases of müllerian mucinous cystadenoma/cystadenofibroma to highlight the notable characteristics of this entity, including gross, cytologic, and architectural features that aid in the distinction from müllerian mucinous borderline tumors as well as, rarely, metastatic tumors. The patients ranged in age from 26 to 85 yr old. Bilateral ovarian involvement was frequent (40%). The ovaries ranged from 2.3 to 26 cm in greatest dimension. Most were multicystic (18 cases) and contained tenacious mucoid material (14 cases). All cases demonstrated predominantly columnar mucinous epithelium with abundant pale-pink cytoplasm. A minor component of ciliated and endometrioid epithelium was seen in 15 and 2 cases, respectively. Broad papillary formations were frequently encountered (9 cases) as was epithelial papillary tufting comprising <10% of the tumor (6 cases). Endometriosis was present in 9 cases, with a transition from endometriosis to mucinous epithelium noted in 8 cases. This series highlights the morphologic features of a relatively uncommon, benign, endometriosis-associated ovarian tumor that may be confused with a müllerian mucinous borderline tumor or bland metastatic mucinous tumors. It also provides an argument for the terminology "müllerian mucinous cystadenoma" or "cystadenofibroma" rather than "seromucinous cystadenoma" due to the frequent association with endometriosis as well as the dominant mucinous epithelium.

Hyperreactio Luteinalis (Multiple Luteinized Follicle Cysts): A Report of 10 Cases.

Hyperreactio luteinalis is a rare entity arising in pregnancy and in the setting of gestational trophoblastic diseases (ie choriocarcinoma, molar pregnancy) that presents with, typically, bilateral ovarian enlargement due to numerous follicle cysts. While the phenomenon is benign and spontaneously regresses following delivery or treatment, a specimen may be seen in pathology when oophorectomy or cystectomy is performed to exclude malignancy or to manage acute complications such as torsion. Such resections may exhibit overlapping microscopic features with cystic granulosa cell tumors. We thus reviewed 10 cases of hyperreactio luteinalis in the setting of pregnancy, the largest pathologic cohort to date, to highlight notable features of this disorder. Patients ranged from 22 to 30 yr old. Most patients (n=6) presented at time of cesarean section with incidentally discovered ovarian masses. Three patients presented in the postpartum period, and 1 underwent surgery at 28 wk gestation due to the finding of a unilateral ovarian mass. The ovaries ranged from 8.5 to 29 cm and were multicystic and bilateral in 8 of the cases. Histologic examination demonstrated multiple, variably sized cystic follicles lined by a granulosa cell layer of varying thickness and theca cells with marked eosinophilic cytoplasm. Stromal edema was often prominent, with theca cells occasionally noted in nests, cords, and as single cells in foci of edema. Mitoses were generally seen more often in the granulosa cell layer (mean=2.6 per high power fields) compared with the theca cell layer (mean=1 per 10 high power fields). This series documents the key features of hyperreactio luteinalis that differentiate it from the other benign mass forming lesions encountered in pregnancy, most notably large solitary follicle cyst of pregnancy and puerperium, as well as cystic granulosa cell tumors, especially the juvenile variant, which may also present during pregnancy. Of particular use in differentiating them from juvenile granulosa cell tumor is the absence of pale or vacuolated cytoplasm and solid growth of granulosa cells in cases of hyperreactio luteinalis.

Follicle Cysts of the Ovary: A Report of 30 Cases of a Common Benign Lesion Emphasizing its Unusual Clinical and Pathologic Aspects.

The common ovarian follicle cyst is typically straightforward from both clinical and pathologic perspectives, but may have a variety of unusual features from both aspects at various stages of life. Lack of familiarity with these may lead to diagnostic quandaries, the most common of which is distinguishing between a follicle cyst and cystic granulosa cell tumor of either adult or juvenile type. We reviewed 30 cases of follicle cysts, all sent in consultation, to highlight unusual aspects of a common lesion. Patients ranged from 3 d to 47 yr old. Clinical presentations included precocious puberty, pelvic pain, or an incidentally discovered pelvic mass, including those occurring in neonates and in 2 adults with pituitary adenomas, one of which was diagnosed 3 yr after presentation with the ovarian cyst. Size ranged from 0.5 cm (deflated) to 18.5 cm, with 7 exceeding 8 cm in greatest dimension. Twelve cases demonstrated small satellite cystic follicles in the wall of the dominant cyst. The granulosa cell layer varied in thickness and mitotic activity (which ranged from 1 to 36 per 10 HPF), but uniformly displayed round nuclei that lacked nuclear grooves. Luteinization of the granulosa cell layer, theca layer, or both was seen across all clinical scenarios, with unluteinized cysts being most common in precocious puberty patients. This series documents that although typically smaller, a subset of follicle cysts are the same size as cystic granulosa cell tumors and the 2 entities may be grossly indistinguishable. Helpful clues to the diagnosis of follicle cyst are the lack of nuclear grooves (vs. adult granulosa cell tumor) and lack of invagination of granulosa cells into the cyst wall (vs. both forms of granulosa cell tumor). Mitoses in the granulosa cells are of no aid in the differential with either form of granulosa cell tumor as follicle cysts may exhibit brisk mitotic activity. Our series highlights some of the unusual clinical aspects, one relatively well known-an association with isosexual precocity, but 2 not as widely known, those occurring in neonates and those due to a pituitary adenoma, the latter sometimes not being discovered until a few years after presentation with a follicle cyst.

Nuclear Beta-Catenin Expression in Endometrioid Intraepithelial Neoplasia (Atypical Hyperplasia) Does Not Predict Carcinoma on Subsequent Hysterectomy.

Beta-catenin (BC) mutations are associated with a high risk of recurrence in otherwise low-grade, early-stage uterine endometrioid adenocarcinomas. Recent literature suggests nuclear BC expression by immunohistochemistry is highly sensitive and specific for BC mutations. The significance of BC expression in endometrioid intraepithelial neoplasia (EIN/atypical hyperplasia) and its relationship to altered differentiation patterns in EIN has yet to be fully explored. Cases meeting current diagnostic criteria for EIN based on H&E examination were obtained from 2 institutions (years 1999-2014). Patterns of altered differentiation (eg, tubal, squamous morular metaplasia, mucinous, secretory) were noted. Representative blocks were stained for BC, and expression patterns recorded. Follow-up and demographic data was obtained from the electronic medical record. Ninety-six cases were included (84 biopsies, 12 hysterectomies). BC nuclear expression was identified in 41 cases (42.7%), with 33 of 41 demonstrating foci of nonmorular BC staining. BC staining in any component of EIN was not significantly associated with the presence of carcinoma on subsequent hysterectomy (P=0.79). When restricting to nonmorular BC, the results were the same (P=0.56). Cases with tubal differentiation were significantly less likely to demonstrate nonmorular BC than cases with no specific pattern of differentiation (P<0.01). EIN frequently demonstrates BC nuclear positivity, especially in cases without tubal differentiation. BC nuclear expression in EIN does not appear to be associated with an increased likelihood of carcinoma on subsequent hysterectomy. Our results do not support routine use of BC immunohistochemistry as a prognostic biomarker in cases of EIN.

A Clinical and Pathologic Exploration of Suspected Peritoneal Endometriotic Lesions.

Endometriosis is generally histopathologically defined as the presence of at least 2 of the following: endometrial stroma, Müllerian epithelium, and/or hemosiderin-laden macrophages (HLM). Despite clinically evident endometriotic lesions, biopsies are frequently nondiagnostic. In this study, we conducted a large-scale review of biopsies of lesions clinically thought to represent endometriosis and correlate the histologic findings with clinical appearance to expand sensitivity of the pathologic definition of endometriosis, particularly in patients on hormonal therapy. In all, 112 biopsies from 78 patients (mean age=25, range 18-39 yr) were reviewed for histopathologic features suggestive of or diagnostic for endometriosis including the presence of endometrial stroma, Müllerian epithelium, dystrophic calcifications, HLM, chronic inflammation, adhesions, and vascular proliferation. Endometriosis was confirmed by pathologic criteria in 37 of 78 patients (47%). Biopsies from patients on hormonal therapy (n=62, 80%) were significantly less likely to meet pathologic criteria for endometriosis (P=0.01). Nondiagnostic biopsies (70/112; 63%) frequently displayed HLM (20%), chronic inflammation (29%), dystrophic calcifications (26%), vascular proliferation (20%), or adhesions (20%) and were significantly more likely to have a vascular clinical appearance (P=0.01). Diagnostic biopsies (42/112; 38%) were more likely to have a blue/black clinical appearance (P=0.03), demonstrate HLM (P=0.004), and display pseudodecidualization (P=0.05). Patients with a high clinical suspicion of endometriosis have a range of histologic findings, with less than half meeting the current histopathologic criteria for diagnosing endometriosis. Given the heterogeneous histopathologic appearance, revision of the histologic criteria may be warranted with further exploration, particularly for lesions with predominantly vascular features.

Low-grade Appendiceal Mucinous Neoplasm and Endometriosis: Incidental Coincident Pathologies at Cesarean Section.

Incidental pathologic findings at the time of Cesarean section are exceedingly uncommon. Similarly, occult low-grade appendiceal mucinous neoplasms and other noninflammatory, non-neoplastic appendiceal pathologies are rare, although appendiceal neoplasia, most commonly well-differentiated neuroendocrine tumors, may be found during evaluation of acute appendicitis. Here we report the first case of incidental coincident low-grade appendiceal mucinous tumor and endometriosis involving the appendix at the time of Cesarean section. We highlight pitfalls in the histopathologic evaluation of these processes, particularly given the setting of decidualization of ectopic endometrial stroma, as well as the prognostic implications of low-grade appendiceal mucinous tumors to emphasize the importance of clinicopathologic correlation and careful intraoperative examination of the appendix and other visible structures during Cesarean section.

Ectopic Fetal Hepatic Tissue in the Placenta.

When an unusual intraplacental lesion is identified during pathologic examination, it becomes of substantial import to determine whether it represents a normal structure, metastasis from the mother, or a primary benign tumor, including those secondary to abnormal embryologic development versus a primary malignant placental tumor. In this case report, we identified an incidental nest of intraplacental cells with nondiagnostic morphology and negative initial Glypican-3 stain in a healthy 35-wk gestation. This negative result prompted a broadening of the differential before ultimately determining this lesion was indeed ectopic liver with positive Arginase-1 and HepPar-1 staining. This may represent the mature hepatocyte phenotype within the lesional cells of this near-term birth, a dichotomy not previously discussed in the literature, which focuses on the fetal hepatocyte phenotype, also rarely seen. In this report, we summarize the previous literature regarding intraplacental ectopic liver, and we propose a sensitive approach to suspected ectopic liver of the placenta that may be sufficient to capture both the fetal and mature hepatocyte immunophenotypes. This approach may extend to other related pathologies including assessment of suspected intraumbilical hepatocytes.

Classic Vulvar Intraepithelial Neoplasia With Superimposed Lichen Simplex Chronicus: A Unique Variant Mimicking Differentiated Vulvar Intraepithelial Neoplasia.

High-grade vulvar intraepithelial neoplasia, a precursor lesion to vulvar squamous cell carcinoma, is subdivided into 2 types, classic or usual vulvar intraepithelial neoplasia (CVIN) and differentiated vulvar intraepithelial neoplasia (DVIN). CVIN, which is a human papilloma virus (HPV)-dependent lesion, is typically distinguished from DVIN, a p53 mutation-dependent process, by its distinct histomorphologic and immunohistochemical characteristics. However, distinguishing between the 2 entities becomes challenging in cases of CVIN with superimposed inflammatory changes, especially lichen simplex chronicus (LSC). Twelve cases of DVIN, 9 cases of LSC, and 9 cases of CVIN with superimposed LSC were assessed for a number of morphologic features, including hyperkeratosis, hypergranulosis, acanthosis, hypercellularity, abnormal maturation (i.e. abnormal keratinization close to the base and/or dyskeratosis), hyperchromasia, and basal atypia. Immunohistochemistry for p53, p16, and MIB-1 was performed for all cases. When sufficient tissue was available, HPV genotyping was performed for cases of CVIN with superimposed LSC. DVIN uniformly demonstrated abnormal maturation, and atypia involving the basal cell layer; they were all p16 negative and demonstrated p53 positivity of moderate to strong intensity in a basal and parabasal distribution. CVIN with superimposed LSC frequently displayed hyperchromasia involving the basal 3 to 4 cell layers, basal to full-thickness atypia, and apoptosis. CVIN with superimposed LSC demonstrated intense p16 positivity extending from the basal cells to the mid-epithelium and a reduction or loss of staining in maturing keratinocytes. P53 staining revealed a unique pattern of parabasal and mid-epithelial weak to moderate staining with sparing of the basal layer. Cases of LSC demonstrated heterogenous p53 positivity and were negative for p16. MIB-1 staining showed a similar range of positivity for all diagnoses. HPV genotyping revealed HPV 16 in all 5 cases of CVIN with LSC that underwent testing. We conclude that, although CVIN with superimposed LSC can closely resemble DVIN, morphologic features such as nuclear hyperchromasia uniformly involving the basal 3 to 4 cell layers, apoptosis, and absent or less pronounced cytoplasmic maturation are more suggestive of CVIN with superimposed LSC. In cases where the morphology remains ambiguous, immunohistochemistry for both p16 and p53 can be helpful. In particular, p53 parabasal and mid-epithelial staining without involvement of the basal layer appears to be a characteristic finding in CVIN with superimposed LSC. MIB-1 staining is of little utility in distinguishing between these entities and should not be routinely performed.

Extramammary Paget Disease of the Vulva: A Case Series Examining Treatment, Recurrence, and Malignant Transformation.

OBJECTIVES: Extramammary Paget disease (EMPD) of the vulva is a rare lesion with a high recurrence rate ranging from 12% to 61%. The rate of underlying adenocarcinoma varies, but in the largest series was reported at 4%. Given the rarity of the disease there is a paucity of data to optimize treatment. This study aims to describe the management and recurrence patterns in a tertiary care setting and to offer suggestions for management in a modern-day setting. METHODS: Patients with pathologically confirmed EMPD treated from 2000 to 2015 were retrospectively identified using an IRB approved database. Clinical data were abstracted from the electronic medical record. Pathology underwent central review. RESULTS: Forty-four patients met criteria and underwent central pathology review. Forty-two patients were treated with surgical excision. Alternative treatment modalities included Mohs surgery in 3 patients and medical therapy in 20 patients. The median number of surgical procedures was 1 and the number of procedures ranged from 1 to 16. Twenty-five patients (56.8%) had recurrent disease with a median of 2 (1-6) recurrences per patient. The median disease-free interval was 28.7 months with a median follow up of 45.8 months (1.2-178.9 months). Three patients (7%) had invasive cancer and 7 patients (16%) were diagnosed with a separate malignancy at or following diagnosis of EMPD. Despite radical resection, the majority of patients had positive margins and there was no significant difference in disease recurrence between simple and radical resection (P = 0.69). CONCLUSIONS: Patients with EMPD in this series have a high rate of recurrence. Many undergo multi-modal therapy often with multiple providers. However, patients experience relatively long disease-free intervals with a low rate of associated malignancy. We propose an algorithm for management that focuses on symptom control and minimizing morbidity of treatment intervention once invasive disease has been excluded.

Differentiated exophytic vulvar intraepithelial lesions are genetically distinct from keratinizing squamous cell carcinomas and contain mutations in PIK3CA.

Human papillomavirus-negative keratinizing vulvar cancers typically harbor TP53 mutations as do their precursors, differentiated vulvar intraepithelial neoplasia. However, atypical verruciform proliferations are also associated with these malignancies and their pathogenesis is poorly understood. This study compared 11 atypical verruciform lesions, including atypical verruciform hyperplasia, vulvar acanthosis with altered differentiation, and verruciform lichen simplex chronicus, with 14 human papillomavirus-negative keratinizing squamous cell carcinomas. Extracted tissue DNA was subjected to targeted massively parallel sequencing of the exonic regions of 300 genes. Eight (73%) and six (55%) of eleven atypical verruciform lesions contained mutations in PIK3CA and ARID2, respectively. No TP53 mutations were identified. Eleven (79%) and five (36%) of fourteen keratinizing squamous cell carcinomas tested contained TP53 and CDKN2A mutations, respectively. Keratinizing squamous cell carcinomas displayed the majority of copy number variations with some variations (7p gain and 8p loss) shared by some cases in both groups. One patient developed atypical verruciform lesions with PIK3CA mutations followed by a keratinizing carcinoma with mutations in both PIK3CA and TP53. This study, for the first time segregates atypical verruciform lesions by virtue of a unique genotype (PIK3CA mutant/TP53 wild type) illustrating an example of progression to a TP53-mutated keratinizing carcinoma. The findings indicate that although PIK3CA mutations are found in <10% of vulvar squamous cell carcinomas, they may be specific for a particular pathway involving atypical verruciform lesions, which could function as either a direct precursor or a risk factor for vulvar squamous cell carcinoma. Given the presence of a molecular signature, we propose the term 'differentiated exophytic vulvar intraepithelial lesion' for this group. Whether they function as direct precursors to a less common form of squamous cell carcinoma will require further study, but carcinomas associated with these lesions might warrant testing for PIK3CA mutations to address this question.

Universal Screening for Mismatch-Repair Deficiency in Endometrial Cancers to Identify Patients With Lynch Syndrome and Lynch-like Syndrome.

Although consensus has yet to be reached on universal mismatch-repair (MMR) protein immunohistochemical (IHC) screening for Lynch syndrome (LS) in endometrial cancer (EC), an increasing number of institutions have adopted universal screening protocols similar to those used for colorectal carcinoma. Here we describe our institution's experience with a prospective universal screening protocol in which all ECs resected over a period of 19 months (n=242) were screened for MLH1, PMS2, MSH2, and MSH6 deficiencies using IHC, followed by MLH1 promoter methylation testing when appropriate. When consent was obtained, tumor samples underwent next-generation sequencing. A total of 11 unmethylated MMR-deficient cases (4.5% of cohort) were identified through IHC screening. Germline testing was performed in 10 cases and confirmed LS in 4 patients (1.7% of cohort). Of our 4 confirmed LS cases, 1 did not meet traditional LS screening criteria (eg, age below 50 y, Revised Bethesda criteria). In addition, universal screening identified 6 germline-negative MMR-deficient nonmethylated cases, 4 of which occurred in women older than 50. Although our next-generation sequencing data suggest somatic mutations in 4 of these cases, it is possible that these cases may represent cases of "Lynch-like syndrome." We conclude that a subset of LS cases could be missed using traditional screening guidelines. The value of screening for Lynch-like syndrome has yet to be determined. Although the cost-effectiveness of universal screening in EC has yet to be elucidated, we conclude that universal IHC screening is currently a reasonable, and arguably superior, approach to screening for LS.

The Role of Endometrial Biopsy in the Preoperative Detection of Uterine Leiomyosarcoma.

STUDY OBJECTIVE: To assess the sensitivity of preoperative endometrial biopsy in detection of uterine leiomyosarcoma (ULMS). STUDY DESIGN: Retrospective analysis of a prospectively collected database (Canadian Task Force III). SETTING: Two academic tertiary referral centers. PATIENTS: All cases of ULMS treated at participating institutions between January 2005 and August 2012 were identified following IRB approval. INTERVENTIONS: Abstracted data included demographics, preoperative evaluation, presenting symptom, surgical management, pathology and clinical outcomes. Chi-square tests were used for statistical analysis. MEASUREMENTS AND MAIN RESULTS: 329 cases were identified, of which 152 cases had complete pathologic data available for review. Sixty-eight (45%) of 152 patients had endometrial sampling prior to surgery. Patients with postmenopausal bleeding were significantly more likely to be biopsied preoperatively (51.6% vs 9.5%, p = <.0001). Of those sampled, 43 (63%) underwent endometrial pipelle biopsies and 25 (37%) had dilation and curettage. Endometrial sampling was significantly more likely to detect a concern for malignancy in patients who presented with postmenopausal bleeding (72.7% vs 32.3%, p = 0.002), however it was less likely to detect malignancy in patients with abnormal premenopausal bleeding (31.8% vs 64.3%, p = .02), compared to other presenting symptoms. Overall, 51.5% of patients with ULMS on final pathology had preoperative endometrial biopsies in which leiomyosarcoma or atypical spindle cell proliferation were diagnosed, whereas 35.5% of the pre-operative biopsies identified ULMS specifically. CONCLUSIONS: The sensitivity of an endometrial biopsy to detect ULMS is low, illustrating the difficulty of diagnosing ULMS preoperatively. As expected, the probability that an endometrial biopsy will detect ULMS or a related worrisome pathological finding is higher for patients with post-menopausal bleeding. Thus, benign endometrial biopsy results, particularly in pre-menopausal patients, should be interpreted with caution if there is suspicion for leiomyosarcoma. However, a positive or suspicious result can play an important role in the subsequent management of patients with ULMS, even if the absolute numbers of affected patients are small.

Uterine Tumors Resembling Ovarian Sex Cord Tumors: A Clinicopathologic Study of 75 Cases Emphasizing Features Predicting Adverse Outcome and Differential Diagnosis.

Uterine tumors resembling ovarian sex cord tumors (UTROSCTs), first characterized by Drs Clement and Scully in 1976, are rare neoplasms showing clinical, morphologic, and immunohistochemical overlap with a number of other uterine tumors, most being mesenchymal. Criteria for aggressive behavior are not clearly established. We report 75 tumors from patients ranging from 21 to 84 (mean=52.4) years. Seventy-one patients were treated by hysterectomy and 4 by conservative total excision. Thirty-eight tumors were intramyometrial, 34 submucosal, and 3 cervical; they ranged from 0.6 to 20 (mean=4.9) cm and were typically tan-yellow. Sixty-eight neoplasms were well-circumscribed and 7 had infiltrative borders (4 only minimally). In 56 tumors, a smooth muscle component was intimately admixed with the neoplastic cells ("pseudoinfiltration"; extensive in 29). Architectural patterns included cords (n=53), diffuse (n=51), hollow tubules (n=48), nests (n=38), trabeculae (n=37), retiform (n=23), solid tubules (n=21), pseudoangiomatoid (n=11), pseudopapillary (n=4), and whorled (n=2); typically, more than 1 pattern was seen. Tumor cells were epithelioid (n=62), epithelioid and spindled (n=12), or spindled (n=1) and/or rhabdoid (n=20; extensive in 2). Cytologic atypia was absent to mild in 57, moderate in 16, and moderate to severe in 2 tumors. Fifty-seven UTROSCTs had ≤2mitoses/10 high power fields (HPF), 12 had 3 to 5/10 HPF, and 6 >5/10 HPF. Necrosis was present in 3 and lymphovascular invasion in 1. Tumor cells showed a polyphenotypic immunohistochemical profile (with positivity for sex cord, smooth muscle, and epithelial markers), most commonly inhibin (17/33+) and calretinin (22/31+) positive. Five of 58 patients with follow-up (22 to 192; mean=73.2 mo) had recurrences/metastases from 30 to 144 months, and 2 died of disease. Malignant tumors showed >3 of the following 5 features compared with benign tumors: size >5 cm, at least moderate cytologic atypia, ≥3 mitoses/10 HPF, infiltrative borders, and necrosis. One of the 5 malignant tumors showed an extensive rhabdoid morphology. UTROSCTs are uncommon, show a wide morphologic spectrum, often pose problems in differential diagnosis, and typically have a benign outcome. Rare tumors are associated with late recurrences and a combination of more than 3 of the 5 features listed above predicted aggressive behavior in this series.