Ovarian tumors and tumor-like lesions in the first three decades

Sex Cord-Stromal Tumors of the Ovary: An Update and Review. Part I - Pure Ovarian Stromal Tumors

In two separate reviews, we review the time-honored but still frequently challenging features of ovarian sex cord-stromal tumors, and also emphasize new developments including unusual morphologic appearances that, despite the relative rarity of many of the tumors, result in a disproportionate number of differential diagnostic problems, variant immunohistochemical profiles, and specific molecular and syndromic associations. These neoplasms are also of historical interest as current knowledge is still based in significant part on the contributions of 2 giants of gynecologic pathology, Dr Robert Meyer and Dr Robert E. Scully. In part I, we present the major clinical, pathologic, and genomic features of the pure ovarian stromal tumors including comments on differential diagnosis and briefly note significant historical contributions. In part II we will discuss pure sex cord and sex cord-stromal tumors.

A comprehensive population-based study of malignant ovarian tumors, including histologic and immunohistochemical review, in children and adolescents 0-19 years old in Sweden between 1970 and 2014

OBJECTIVES

Ovarian tumors in the pediatric population are rare. The incidence and frequency of subtypes differ between children and adults. Although not all tumors are aggressive, they may still lead to morbidity. The goal of this study was a comprehensive review of malignant ovarian tumors in children and adolescents diagnosed and registered in Sweden.

METHODS

Individuals were identified through a search in the National Cancer Register, limited for ages 0-19, years 1970-2014. Stored tumor diagnostic material from regional biobanks was retrieved and reviewed.

RESULTS

The study includes 345 individuals with ovarian tumors and 70.7% of them were between 15 and 19 years at time of diagnosis. No differences in incidence over time or geographic location were identified. The average follow-up time was 21.2 years and 5-year survival was 88.4%. Survival was similar in the different time periods, except for 1970-1979. Review was possible for 260 cases, resulting in 85 epithelial tumors, 121 GCTs, 47 SCSTs and 7 others. For age 0-4 years SCSTs dominated (85.7%), for 5-9- and 10-14-years GCTs dominated (70,8% and 75.0% respectively), and for age 15-19 years epithelial tumors dominated (43.8%). There was a strong agreement between review diagnosis and original diagnosis (Cohen's κ 0.944). Differentiating between entities within the sex cord-stromal group posed the biggest diagnostic challenge.

CONCLUSIONS

Ovarian tumors in children and adolescents are rare and distinct from their adult counterparts regarding incidence and frequency. There was a strong concurrence between original and review diagnoses. The greatest diagnostic difficulty was subtyping of epithelial tumors and differentiating between tumors within the SCST group.

Yolk Sac Tumor of the Ovary: A Report of 150 Cases and Review of the Literature

One hundred fifty yolk sac tumors (YSTs) of the ovary in patients from 1 to 61 (mean: 21.5) years of age are described; 75% of the patients were in the second and third decades and only 1 was above 50 years of age. The clinical manifestations were typically related to a fast-growing adnexal mass; endocrine manifestations (hirsutism) were present in only 2 cases. The tumors were all unilateral and 70% were ≥15 cm; an associated dermoid cyst was present in 20 cases. The tumors were solid and cystic in 57% of the cases, 25% were multicystic, and 18% uniformly solid. The solid tissue was typically tan to pink or yellow and often friable with hemorrhage and necrosis; smaller solid neoplasms were sometime uniformly yellow. The most common histologic pattern was reticular composed of an irregular meshwork of spaces that was conspicuous in 68% of the neoplasms but present to at least a minor degree in all of them. That appearance almost always merged with small to large cysts that were prominent in about 40% of tumors. In 25% of the tumors, cysts sometimes associated with a cellular stroma (the polyvesicular pattern), were present but conspicuous in only half these cases. One third of the tumors had a labyrinthine pattern, 22% glands, and 6% a festoon pattern. Papillae with a central blood vessel (Schiller-Duval bodies) were seen in one-third of the tumors but were numerous in only 5% of them. Nonspecific appearing papillae were seen in 10% of the tumors. A solid growth of cells with pale cytoplasm was seen in one-third of the tumors but was conspicuous in only half of that subset. The solid appearance was typically reminiscent of that of dysgerminoma, but lacked the septa and lymphocytic infiltrate of that neoplasm. Nine tumors had a component of cells with scant cytoplasm resulting in a blastema-like appearance and 3 had cells with abundant clear cytoplasm. Cords and clusters of cells were common but did not dominate the microscopic appearance. The stroma typically had a nonspecific collagenous to edematous appearance. Stromal luteinization was seen in 12 tumors; in 5 this was likely due to the patient being pregnant. Two tumors had minor foci of cells that resembled hepatocytes. Hyaline bodies were seen in most of the tumors and were often conspicuous. The neoplastic cells typically had modest amounts of lightly staining cytoplasm and only mild nuclear pleomorphism. Cells lining cysts were often flattened sometimes resulting in a deceptively innocuous appearance. Many of the tumors (mostly consultation cases), caused diagnostic difficulty; tumors in the differential diagnosis included clear cell carcinoma, embryonal carcinoma, Sertoli-Leydig cell tumor, and juvenile granulosa cell tumor. The patient age and marked elevation of the serum alpha-fetoprotein level (if measured) is helpful in many of these considerations. The overtly malignant gross appearance of most YSTs contrasts with certain other tumors in the differential and the association of some YSTs with dermoid cyst and many clear cell carcinomas with endometriosis may be helpful. The vast majority of ovarian YSTs are dominated microscopically by merging of reticular and cystic patterns which, although focally mimicked by other neoplasms, are in general characteristic, and distinctive features of other neoplasms are absent. Immunohistochemistry, particularly for alpha-fetoprotein and glypican 3, and lack of staining for various markers of other neoplasms is helpful but overlap exists and these results must be considered in the context of the overall clinical, gross, and microscopic features. YSTs dominated by hepatoid and glandular features are rare and their categorization as YSTs should be done cautiously if thoroughly sampled tumors show no evidence of classic features of YST emphasized herein and first elaborated by the Danish investigator Gunnar Teilum whose seminal observations have stood the test of time.

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.

Malignant Mixed Germ Cell Tumors of the Ovary: An Analysis of 100 Cases Emphasizing the Frequency and Interrelationships of Their Tumor Types

One hundred malignant mixed germ cell tumors of the ovary that occurred in patients 3 to 55 years (mean: 20 y) of age are described. The clinical presentation was usually that of any highly malignant tumor of the ovary (abdominal pain and distension), but rarely (3 cases) endocrine manifestations were present. The tumors were usually unilateral (96%), ranged from 4 to 38 cm (mean: 16 cm), and were uniformly solid or, more often, solid and cystic; occasionally the typical appearance of dysgerminoma could be appreciated. The most common tumor type was yolk sac tumor (91%), followed by dysgerminoma (61%), immature teratoma (58%), embryonal carcinoma (38%), and choriocarcinoma (11%). A variety of admixtures were encountered; dysgerminoma and yolk sac tumor was the most common combination (25% of the tumors) with the 2 components often being sharply demarcated. Immature teratoma and yolk sac tumor was the next most common pairing (20%) followed by yolk sac tumor and embryonal carcinoma, with or without immature teratoma (16%). Tumors with a choriocarcinoma component had the most varied combinations of tumor types. Embryoid bodies were seen in 21% of the tumors, most often as fragmented forms arranged in a nodular manner with yolk sac tumor and/or embryonal carcinoma; uncommonly they occurred singly or in clusters. Numerous confluent well-formed embryoid bodies (polyembryoma) were prominent in 2 tumors. Three tumors had a focal diffuse embryoma pattern. The specific tumor types showed the known diverse spectrum of microscopic appearances, but the frequent haphazard arrangement of 2 or more subtypes often resulted in complex morphology. Overgrowth of another neoplastic component, most often primitive neuroectodermal tumor, occurred in 10% of the tumors further complicating the histologic picture. This is the largest series of ovarian malignant mixed germ cell tumors reported and details their characteristics including associations of their subtypes and the frequent apparent role of embryoid bodies in giving rise to yolk sac tumor and embryonal carcinoma components.

Dysgerminoma of the Ovary: An Analysis of 140 Cases Emphasizing Unusual Microscopic Findings and Resultant Diagnostic Problems

One-hundred fourty pure dysgerminomas were evaluated with particular focus on the microscopic features as seen in 125 cases with available slides. The patients ranged from 8 to 59 years of age (mean, 24.1 y). The tumors, bilateral in 4% of the cases and with a mean tumor diameter of 13 cm, were typically soft, lobulated, homogeneous, and creamy white to tan to yellow but necrosis was found in 13%, hemorrhage in 20%, and focal cystic change in 15%. On microscopic examination, the patterns and other notable features encountered, including their frequency, were as follows: an alveolar pattern resulting from delicate fibrovascular septa (51%), diffuse (33%), macronodular (14%), insular (26%), cords (28%), solid tubular (17%), microspaces (sometimes simulating glands) (12%), follicle-like spaces (5%), prominent fibrous bands (65%), stromal edema (56%), stromal luteinization (9%), granulomatous infiltrate (46%), lymphocytic infiltrate (100%), Langhans cell type giant cells (35%), syncytiotrophoblast giant cells (6%), prominent population of cells with pale to clear cytoplasm (73%), cells with amphophilic to eosinophilic cytoplasm (53%) and vacuolated occasionally signet ring-like cells (7%). Various constellations of the above findings often resulted in an appearance different from that usually portrayed in the literature and certain tumors of very different nature being in the differential such as undifferentiated carcinoma not otherwise specified, small cell carcinoma of hypercalcemic type, and malignant lymphoma. The correct diagnosis can be arrived at by considering the usual relative youth of the patient, often rather characteristic gross features, and most crucially careful attention to the microscopic features and awareness of variant morphologic findings. Those that are particularly problematic based on this study are diffuse growth with inconspicuous fibrovascular septa, macronodules, cords, solid tubular formations, spaces ranging from small to large, and mimicking glands or follicles, prominent fibrous to edematous stroma, and cells with amphophilic to eosinophilic cytoplasm. According to the degree of difficulty and confidence of the interpreter, well-known immunohistochemical features of dysgerminoma, which largely differ from those of other neoplasms in the differential, will aid if felt indicated.

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.

SWI/SNF-deficient malignancies of the female genital tract

Mutations and other molecular events involving subunits of the SWI/SNF chromatin remodelling complex are common in a wide variety of malignancies, including those arising at various sites in the female genital tract. Endometrioid and clear cell carcinomas in the uterine corpus and ovary not uncommonly contain mutations in ARID1A and these also occur in other endometriosis-associated ovarian neoplasms such as seromucinous tumours. In these organs, mutations in SMARCA4, SMARCB1, ARID1A and ARID1B (with subsequent loss of corresponding protein expression as a reliable surrogate) are relatively common in undifferentiated carcinomas, including the undifferentiated component of dedifferentiated carcinoma. SMARCA4 mutations are extremely common (almost ubiquitous) in small cell carcinoma of the ovary of hypercalcaemic type (SCCOHT), occurring in about 98% of these neoplasms, often in association with epigenetic SMARCA2 loss. SMARCB1-deficient vulval neoplasms include epithelioid sarcoma and myoepithelial carcinoma, as well as related malignancies which defy easy classification. Recently the spectrum of SWI/SNF deficient female genital malignancies has been expanded to include SMARCA4-deficient undifferentiated uterine sarcoma and mural nodules of anaplastic carcinoma in ovarian mucinous neoplasms.

An unusual appearance of a serous ovarian cyst coexisting with endometriosis: A case report

INTRODUCTION

Endometriosis is an estrogen-dependent disease that can provoke fibrosis through the elevated concentration of TGF-β. Endometriosis-related fibrosis often manifests as pelvic adhesions, and it is almost always observed microscopically when examining the endometriotic lesions. Here we are reporting, for the first time in literature, an unusual gross appearance of a serous ovarian cyst that coexisted with endometriosis.

PRESENTATION OF CASE

A 32-year-old G1P2 woman presented to our hospital complaining of the inability to conceive. She was scheduled to have an exploratory laparoscopy. Upon reaching the abdominal cavity, several islands of endometriosis and a left ovarian mass were spotted. The ovarian mass was resected by an excisional biopsy and the pathologic examination showed a benign ovarian cyst with extreme fibrosis in its wall.

DISCUSSION

Endometriosis often induces a chronic pelvic inflammation, mediated mainly by the over-activated macrophages. These cells secrete many cytokines and growth factors that alter the normal pelvic milieu. TGF-β levels are often elevated within the peritoneal fluid, which stimulate fibroblasts and provoke tissue fibrosis. One study suggested that ovarian stromal fibrosis can induce infertility by impairing folliculogenesis. LH-inhibiting regimens can reverse the stromal fibrosis, and improve the fertility outcomes.

CONCLUSION

The mural fibrosis seen in the cystic wall reflects unrecognized ovarian stromal fibrosis induced by the fibrogenic effects of endometriosis. This process may play a potential role in provoking infertility in patients with endometriosis, and could be reversed by administrating the LH-inhibiting regimens.

Imaging in pediatric ovarian tumors

The spectrum of ovarian tumors in the pediatric population differs significantly from that in adults. Germ cell tumors are the predominant class of ovarian tumors in children, whereas epithelial tumors are the most common in adults. Ultrasonography is the modality of choice for the initial evaluation of pediatric ovarian tumors. Determining the diagnosis based on imaging may prove difficult, and combining the imaging findings with the clinical scenario is very helpful in reaching a differential diagnosis during clinical practice. We will discuss the spectrum of ovarian neoplasms in the pediatric population and describe their clinical, pathologic, and imaging characteristics. A few unique entities related to ovarian tumors, such as growing teratoma syndrome, anti-N-methyl-D-aspartate receptor encephalitis, and hereditary ovarian tumor syndromes, are also discussed. In addition, we will review several entities that may mimic ovarian neoplasms as well as their distinct imaging features.

Identification of recurrent FHL2-GLI2 oncogenic fusion in sclerosing stromal tumors of the ovary

Sclerosing stromal tumor (SST) of the ovary is a rare type of sex cord-stromal tumor (SCST), whose genetic underpinning is currently unknown. Here, using whole-exome, targeted capture and RNA-sequencing, we report recurrent FHL2-GLI2 fusion genes in 65% (17/26) of SSTs and other GLI2 rearrangements in additional 15% (4/26) SSTs, none of which are detected in other types of SCSTs (n = 48) or common cancer types (n = 9,950). The FHL2-GLI2 fusions result in transcriptomic activation of the Sonic Hedgehog (SHH) pathway in SSTs. Expression of the FHL2-GLI2 fusion in vitro leads to the acquisition of phenotypic characteristics of SSTs, increased proliferation, migration and colony formation, and SHH pathway activation. Targeted inhibition of the SHH pathway results in reversal of these oncogenic properties, indicating its role in the pathogenesis of SSTs. Our results demonstrate that the FHL2-GLI2 fusion is likely the oncogenic driver of SSTs, defining a genotypic–phenotypic correlation in ovarian neoplasms.

Little is known about the genetics of sclerosing stromal tumor of the ovary, a rare type of sex cord-stromal tumor. Here, the authors use sequencing strategies to show that in a cohort of 26 tumor samples 65% carry a FHL2-GLI2 fusion gene and demonstrate in vitro that the fusion gene has oncogenic properties.

Ovarian tumors: a survey of selected advances of note during the life of this journal

The author reviews highlights of advances in knowledge concerning ovarian tumor pathology since the time of an essay in the first issue of this Journal written by Dr Robert E. Scully, who, both before and for several decades after the Journal was instituted, made many original contributions to the field and was the major architect of the 1973 World Health Organization classification of ovarian tumors which was much more clear and logical than prior ones. The current review considers the neoplasms in essentially the same order as was done in the first issue of this journal and presents a personal look at the highlights of new information concerning various well-known categories, surface epithelial, germ cell, sex cord-stromal, metastatic neoplasms and briefly, benign so-called tumor-like lesions. Some of the most notable developments are as follows: (1) an orderly approach to the classification of implants of serous borderline tumors into noninvasive and invasive categories; (2) recognition of distinctive micropapillary patterns seen in some borderline tumors and low-grade carcinomas; (3) a remarkable propensity for some endometrioid carcinomas to mimic sex cord- stromal tumors; (4) appreciation of the differences between primary mucinous tumors of intestinal and müllerian types; (5) the importance of distinguishing within primary mucinous carcinomas between expansile and destructive stromal invasion; (6) emphasis on the diagnosis of immature teratoma being based on the presence of primitive-embryonic-appearing tissues; (7) appreciation of variant morphology of cases of struma ovarii which may lead to significant diagnostic problems; (8) subdivision of granulosa cell tumors into adult and juvenile types because of the differing features of the two groups including in the second category the propensity for more malignant neoplasms to be mimicked; (9) recognition of a distinctive form of Sertoli-Leydig cell tumor, the retiform variant, with a propensity to occur in the young; (10) appreciation of a unique highly malignant neoplasm that typically afflicts the young and may be associated with hypercalcemia, so-called small cell carcinoma of hypercalcemic type; (11) greater awareness than was hitherto the case of the propensity for metastatic intestinal adenocarcinoma to mimic primary endometrioid carcinoma and similarly for metastatic mucinous carcinomas to simulate primary mucinous cystic tumors; (12) recognition of the distinctive features of low-grade appendiceal mucinous neoplasms that spread to the ovary and are typically associated with pseudomyxoma peritonei; and (13) appreciation that the histologic spectrum seen in cases of Krukenberg tumor is broader than often previously thought.

Ovarian Sex Cord-Stromal Tumors: Reflections on a 40-Year Experience With a Fascinating Group of Tumors, Including Comments on the Seminal Observations of Robert E. Scully, MD

CONTEXT.—

This year being the 60th anniversary of the publication of the excellent book Endocrine Pathology of the Ovary by John McLean Morris, MD, and Robert E. Scully, MD, the writer reflects on that work and in particular the remarkable contributions of its second author to our knowledge in this area.

OBJECTIVE.—

To review ovarian sex cord-stromal tumors.

DATA SOURCES.—

Literature and personal experience.

CONCLUSIONS.—

The essay begins with remarks on the oftentimes straightforward stromal tumors of the ovary because the commonest of them, the fibroma, dominates from the viewpoint of case numbers. Then, the sclerosing stromal tumor and the peculiar so-called luteinized thecomas of the type associated with sclerosing peritonitis are discussed in greater detail and their wide spectrum is illustrated. Brief mention is made of 2 rare neoplasms: the ovarian myxoma and signet-ring stromal tumor. Discussion then turns to the more recently recognized intriguing tumor tentatively designated microcystic stromal tumor and the commonest malignant tumor in this entire family, the so-called adult granulosa cell tumor, which despite its name may occasionally be seen in young individuals. The second variant of granulosa cell tumor-that which usually, but not always, occurs in the young-the so-called juvenile granulosa cell tumor, is then discussed. In the section of Sertoli-Leydig cell tumors, particular attention is focused on unusual tumors with heterologous elements and the remarkable so-called retiform tumors, which have a predilection for the young, often have distinctive gross features, and exhibit slitlike spaces and papillae. The essay concludes with consideration of the sex cord tumor with annular tubules.

[The value of immunohistochemistry using SMARCA4/BRG1 in the diagnosis of small cell ovarian carcinoma hypercalcemic type. A report of two cases]

Small cell carcinoma of ovary-hypercalcemic type is an undifferentiated carcinoma. We describe two cases in women aged 32 and 29. Both presented with large masses and complete surgical extirpation was impossible. Histologically, the images were similar, with diffuse cell proliferation, accompanied by the presence of follicle-like spaces. In both cases it was necessary to make a differential diagnosis with entities such as adult or juvenile granulosa cell tumour, small cell carcinoma of pulmonary type, dysgerminoma and even peripheral neuroectodermal tumour. The absence of SMARCA4/BRG1 immunostaining proved very useful in the diagnosis of hypercalcemic small cell ovarian carcinoma.

Ovarian sex cord-stromal tumours and their mimics

Sex cord-stromal tumours of the ovary include many of the most morphologically intriguing ovarian neoplasms and albeit many of them are rare, they factor into the differential diagnosis more often than their frequency might suggest. The most common malignant form, the adult granulosa cell tumour, may grossly simulate various surface epithelial neoplasms. Microscopically, confusion with endometrioid carcinoma may occur because the cords and microfollicles of the granulosa cell tumour may be mimicked by endometrioid carcinoma and the latter may have pale nuclei with nuclear grooves. Thorough sampling generally resolves this differential and if not immunohistochemistry aids. Although the adult granulosa cell tumour typically has cells with scant cytoplasm in some cases the tumour cells are luteinised and others have cells with abundant pale cytoplasm. A reticulum stain may be of great aid in indicating whether cells of the type just noted are of granulosa or theca nature. Variations in the morphology of the juvenile variant of granulosa cell tumour that can be diagnostically challenging include those that have a macronodular pattern with scant follicular differentiation, those with marked sclerosis, and those that are unusually pleomorphic. The uncommon but histologically varied Sertoli-Leydig cell tumour is considered, emphasis being placed on the most recently described variant, the retiform pattern, with its potential to mimic surface epithelial neoplasms and even mixed mesodermal tumours. Considering the usual young age of the patient may be paramount in making this tumour come to the mind of the pathologist. The rare pure Sertoli cell tumour is briefly noted as is the sex cord tumour with annular tubules, well known because of its association in some cases with Peutz-Jeghers syndrome. Most do not have that association, however, but have their own interesting features including a greater than average risk, among sex cord stromal tumours, of nodal metastasis and progesterone production, and an occasional development from them of an otherwise typical Sertoli cell tumour. The stromal family includes the common fibroma which is challenging when it is cellular with some mitotic activity and the approach to such neoplasms is reviewed. Emphasis in the consideration of thecoma is placed on its typical cytological features and the overlap with what may be seen in some adult granulosa cell tumours. The review concludes with three fascinating pure stromal tumours all described within the last several decades: the sclerosing stromal tumour, the unusual luteinised thecoma associated with sclerosing peritonitis and the microcystic stromal tumour. The first is sometimes misdiagnosed when pure stromal neoplasms of other types are vascular and may have pseudolobules and it is essential that the pseudolobules of the sclerosing stromal tumour contain a haphazard admixture of fibroblasts and weakly luteinised cells. The remarkable tumours associated with peritonitis exhibit brisk mitotic activity but appear not to have a metastatic potential; they can cause significant problems because of the sclerosing peritonitis. The microcystic stromal tumour may mimic a steroid cell tumour or thecoma but unlike them is inhibin and calretinin negative, and stains for CD10 and β-catenin. It often shows bizarre nuclei atypia but limited mitotic activity and appears to be clinically benign on the basis of still limited experience.

Krukenberg tumors: Seed, route and soil

The aim of this narrative review was to summarize the current evidence on Krukenberg tumors (KTs), addressing what is known on their natural history and their impact on the clinical prognosis and which are the most appropriate management strategies to treat this condition. A literature search was conducted on Pubmed up to December 2016, selecting the most relevant studies on the basis of the scope of the review. KTs are ovarian metastases from primary signet-ring cell carcinomas., characterized by the presence of a sarcoma-like stroma. They have three possible routes of diffusion (lymphatic, peritoneal and hematogenous), but the preferential one is still unclear. Prognosis is dismal. When KTs are encountered in the clinical practice, it is reasonable to offer surgical resection to young, fit patients with limited disease. Palliative surgery should be considered for all patients with symptomatic disease. Further studies should clarify the clinicopathologic characteristics of KTs, their main routes of diffusion, and the possible role of prophylactic oophorectomy, lymphadenectomy and intraperitoneal chemotherapy. Molecular and transitional research should parallel the clinical one to help understanding the natural history of signet-ring cell carcinomas.

Small Cell Carcinoma of the Ovary, Hypercalcemic Type: Clinical and Imaging Review

Small Cell Carcinoma of the Ovary, Hypercalcemic Type (SCCOHT) is a rare, aggressive malignancy with a poor prognosis. Its features are difficult to differentiate from other ovarian malignancies. In this article, we discuss recent advances in our understanding of this rare malignancy including tumor genetics. We also describe demographic, clinical and imaging findings, staging, and treatment options.

Molecular analysis of ovarian mucinous carcinoma reveals different cell of origins

It is believed that a subset of primary ovarian mucinous tumors is derived from mature teratomas [1–5]. To confirm this, we performed microsatellite genotyping using a variety of short tandem repeat makers and analyzed allelotypes of 8 mucinous tumors (4 mucinous carcinomas, 3 atypical proliferative mucinous tumors and 1 mucinous cystadenoma) associated with a teratoma to determine whether they were clonally related. 7 of the 8 mucinous tumors showed complete or a high degree of homozygosity. Among the 6 pairs of tumors with teratoma tissue available for comparison, 5 of 6 showed a high or complete degree of allelotypes matching, which differed from the somatic allelotypes of the normal control tissue. A discrepancy was detected between carcinoma and teratoma in one pair at several loci, with different X-chromosome inactivation patterns revealed by the HUMARA clonality assay. We also investigated the allelotypes of 16 ovarian mucinous carcinomas without a teratoma in young patients (range 13–30) and in 6 older patients (range 40–67) using the same method. None of these tumors showed pure homozygosity. The number of homozygous loci in this cohort was significantly lower than that in the first. Our results suggest first, that most mucinous tumors associated with a teratoma are derived from the teratoma but occasionally they could be collision tumors and second that the majority of pure mucinous tumors in young women in whom a teratoma is not present are not derived from a teratoma.

Small-Cell Carcinoma of the Ovary of Hypercalcemic Type (Malignant Rhabdoid Tumor of the Ovary): A Review with Recent Developments on Pathogenesis

Small-cell carcinoma of the ovary of hypercalcemic type (SCCOHT) is a highly malignant and aggressive tumor and is the most common undifferentiated ovarian malignancy to occur in women younger than 40. SCCOHT is characterized by deleterious germline or somatic mutations in SMARCA4. Given the striking morphologic and molecular similarities between SCCOHT and atypical teratoid/malignant rhabdoid tumor, we propose this should be reflected in a nomenclature change and that SCCOHT be renamed malignant rhabdoid tumor of the ovary. SMARCA4 (BRG1) immunohistochemistry is useful in diagnosis because there is loss of nuclear immunoreactivity in SCCOHT but retention of staining in mimics.

Pseudopapillary Granulosa Cell Tumor: A Case of This Rare Subtype

Background The pseudopapillary pattern of granulosa cell tumor is rare. Case We describe the case of a 35-year-old woman who presented with an initial diagnosis of papillary serous cystadenocarcinoma. Results Evaluation, including immunohistochemistry, led to the diagnosis of pseudopapillary granulosa cell tumor. Conclusion The pseudopapillary pattern of granulosa cell tumor is rare and must be suspected in order to utilize appropriate immunohistochemistry and reach the correct diagnosis. Inhibin positivity is particularly helpful.

A spontaneously occurring malignant ovarian Sertoli cell tumor in a young Sprague Dawley rat

Primary ovarian tumors are generally uncommon in rats used in toxicologic studies. A malignant Sertoli cell tumor was present in the ovary of a 19-week-old female Sprague Dawley rat. Macroscopically, the mass was white and firm, 10 × 13 × 17 mm in size, and located in the right ovary. Histopathologically, the mass was composed of nests of pleomorphic cells, which formed seminiferous-like tubules separated by a thin fibrovascular stroma. The tubules were lined by tumor cells, which had basally located nuclei and abundant eosinophilic and vacuolated cytoplasm. In some areas, the tumor cells were arranged in a retiform growth pattern, mimicking a rete testis/ovarii. Disseminated metastases to the surfaces of the mesentery, spleen and liver were also present. Immunohistochemically, many tumor cells were strongly positive for vimentin, estrogen receptor α and Ki 67. Some tumor cells were positive for pancytokeratin and inhibin α. These findings closely resemble those of an ovarian-derived human malignant Sertoli cell tumor. From our review of the literature, we believe this is the first report of a spontaneous malignant Sertoli cell tumor in the ovary of a young laboratory rat. This case might provide useful historical control information for rat toxicity studies.

CTNNB1 (β-Catenin)-altered Neoplasia: A Review Focusing on Soft Tissue Neoplasms and Parenchymal Lesions of Uncertain Histogenesis

β-catenin (CTNNB1) is a key regulatory molecule of the Wnt signaling pathway, which is important for tissue homeostasis and regulation of cell proliferation, differentiation, and function. Abnormal stabilization and nuclear accumulation of β-catenin as a consequence of missense mutations or alternative molecular mechanisms occurs at a high frequency in a variety of epithelial cancers. In mesenchymal neoplasia, the role of β-catenin has been traditionally considered limited to desmoid-type fibromatosis. However, the spectrum of β-catenin-driven (β-catenin-altered) neoplasia of mesenchymal origin has been steadily widening to include, in addition to desmoid tumors, a variety of benign and intermediate-biology neoplasms of soft tissue (intranodal palisaded myofibroblastoma), head and neck (juvenile nasopharyngeal angiofibroma and sinonasal hemangiopericytoma/glomangiopericytoma), and ovarian (microcystic stromal tumor) origin. In addition, several old and newly reported distinctive site-specific β-catenin-driven parenchymal neoplasms of uncertain histogenesis have been well characterized in recent studies, including solid-pseudopapillary neoplasm of the pancreas and its recently described ovarian counterpart, sclerosing hemangioma of lung and calcifying nested stromal-epithelial tumor of the liver. This review addresses the most relevant pathobiological and differential diagnostic aspects of β-catenin-altered neoplasms with emphasis on site-specific histologic and biological variations. In addition, the morphologic overlap and analogy as well as distinctness between these uncommon tumors will be presented and discussed. Furthermore, a note is made on association of some of these lesions with hereditary tumor syndromes, in particular with the familial adenomatous polyposis coli.