Gonadal Stromal Tumors Research Articles

Fluorescence in-situ hybridization assessment of spindle cell-rich testicular sex cord stromal tumors demonstrates multiple chromosomal gains across histologic subtypes

Spindle cell-rich testicular sex cord-stromal tumors (TSCSTs) comprise a group that includes mostly (but not exclusively): myoid gonadal stromal tumor (MGST), adult granulosa cell tumor (AGCT), and unclassified TSCST. These entities demonstrate histopathologic overlap, and prior genomic studies have failed to identify specific oncogenic drivers. Results of DNA sequencing suggest that different types of spindle cell-rich TSCSTs harbor a recurrent pattern of chromosomal gains. However, these results have not been validated by alternative methods and the extent of these changes within individual tumors remains unknown. We used a combination of commercially available fluorescence in-situ hybridization (FISH) probes (3q11.2, 6p24.3, 6q11.1, 6q23, 7q11.21-q11.22, 9p21.3, 11q13.3, 17p11.2) to enumerate a subset of chromosomes identified as altered (gained) in prior studies. We analyzed 10 cases (3 MGST, 4 unclassified TSCST, 3 AGCT), including 7 that had been previously sequenced. FISH demonstrated gains of chromosomes 3, 6, 7, 9, and 11 above the pre-established threshold (25%) in 50%, 80%, 70%, 20%, and 40% of cases, respectively, with gains of chromosome 17 being present in only 1 unclassified TSCST. The proportion of cells with chromosomal gains ranged from 26% to 60%. Tumors with available copy number data from prior genomic analyses showed a partial discordance between FISH and sequencing results. This study demonstrates that spindle-cell rich TSCSTs harbor a recurrent pattern of chromosomal gains, which are present in variable subsets of neoplastic cells. Further studies are needed to determine if these chromosomal changes represent a mechanism relevant for oncogenesis or a secondary event.

Myoid gonadal stromal tumor of the testis—the novel subtype of testicular gonadal stromal tumors: a case report and review of the literature

BackgroundSex cord gonadal stromal tumors compose less than 10% of all testicular neoplasms and consist of a variety of histological subtypes. In 2016, the World Health Organization introduced a novel subtype, the myoid gonadal stromal tumor, that consists of spindle-shaped cells with immunohistologic features of muscle cells. Only few cases have been reported to date. Due to its rarity and owing to its only recent introduction, the current knowledge about myoid gonadal stromal tumor is limited, and particularly, appropriate clinical management is still ill-defined.Case presentationA 47-year-old man of Caucasian descent presented with nonspecific scrotal discomfort. A roundish and well demarcated hypoechoic mass of 8.5 mm in diameter was detected in the cranial region of the left testis. Serum tumor marker levels were within normal ranges. Testis-sparing surgery revealed a 9-mm whitish, hard mass with sharp surgical margin. Histologically, the neoplasm consisted of microfibrillar tissue with spindle-shaped cells harboring elongated nuclei. Immunohistochemical work-up disclosed expression of desmin, small muscle actin, and S100 protein giving evidence for the myogenic nature of the neoplastic cells. There was no indication of malignancy, neither histologically nor clinically. Follow-up of 1 year was uneventful.ConclusionA literature survey revealed 22 previous cases of myoid gonadal stromal tumor. The median age was 37 years, the median size of the neoplasm was 20 mm, and there was no side-preponderance. Myoid gonadal stromal tumor is not much different from other subtypes of gonadal stromal tumors nor from testicular gem cell tumors regarding age and laterality; however, tumor size is smaller in myoid gonadal stromal tumors than in germ cell tumors. Although rarely performed so far, testis-sparing surgery probably constitutes an appropriate treatment of this neoplasm. Myoid gonadal stromal tumor represents an emerging novel entity of benign testicular new growths that caregivers of patients with testicular tumors should be aware of.

Spermatogonial fate in mice with increased activin A bioactivity and testicular somatic cell tumours.

Adult male fertility depends on spermatogonial stem cells (SSCs) which undergo either self-renewal or differentiation in response to microenvironmental signals. Activin A acts on Sertoli and Leydig cells to regulate key aspects of testis development and function throughout life, including steroid production. Recognising that activin A levels are elevated in many pathophysiological conditions, this study investigates effects of this growth factor on the niche that determines spermatogonial fate. Although activin A can promote differentiation of isolated spermatogonia in vitro, its impacts on SSC and spermatogonial function in vivo are unknown. To assess this, we examined testes of Inha KO mice, which feature elevated activin A levels and bioactivity, and develop gonadal stromal cell tumours as adults. The GFRA1+ SSC-enriched population was more abundant and proliferative in Inha KO compared to wildtype controls, suggesting that chronic elevation of activin A promotes a niche which supports SSC self-renewal. Intriguingly, clusters of GFRA1+/EOMES+/LIN28A- cells, resembling a primitive SSC subset, were frequently observed in tubules adjacent to tumour regions. Transcriptional analyses of Inha KO tumours, tubules adjacent to tumours, and tubules distant from tumour regions revealed disrupted gene expression in each KO group increased in parallel with tumour proximity. Modest transcriptional changes were documented in Inha KO tubules with complete spermatogenesis. Importantly, tumours displaying upregulation of activin responsive genes were also enriched for factors that promote SSC self-renewal, including Gdnf, Igf1, and Fgf2, indicating the tumours generate a supportive microenvironment for SSCs. Tumour cells featured some characteristics of adult Sertoli cells but lacked consistent SOX9 expression and exhibited an enhanced steroidogenic phenotype, which could arise from maintenance or acquisition of a fetal cell identity or acquisition of another somatic phenotype. Tumour regions were also heavily infiltrated with endothelial, peritubular myoid and immune cells, which may contribute to adjacent SSC support. Our data show for the first time that chronically elevated activin A affects SSC fate in vivo. The discovery that testis stromal tumours in the Inha KO mouse create a microenvironment that supports SSC self-renewal but not differentiation offers a strategy for identifying pathways that improve spermatogonial propagation in vitro.

Rare tumors: Opportunities and challenges from the Children’s Oncology Group perspective

While all childhood cancers are rare, tumors that are particularly infrequent or underrepresented within pediatrics are studied under the umbrella of the Children’s Oncology Group Rare Tumor committee, divided into the Retinoblastoma and Infrequent Tumor subcommittees. The Infrequent Tumor subcommittee has traditionally included an emphasis on globally rare tumors such as adrenocortical carcinoma, nasopharyngeal carcinoma, or those tumors that are rare in young children, despite being common in adolescents and young adults, such as colorectal carcinoma, thyroid carcinoma, and melanoma. Pleuropulmonary blastoma, gonadal stromal tumors, pancreatic tumors including pancreatoblastoma, gastrointestinal stromal tumor, nonmelanoma skin cancers, neuroendocrine tumors, and desmoplastic small round cell tumors, as well as other carcinomas are also included under the heading of the Children’s Oncology Group Rare Tumor committee. While substantial challenges exist in rare cancers, inclusion and global collaboration remain key priorities to ensure high quality research to advance care.

Ovarian Fibrothecoma: A Case Report

Introduction: Fibrothecal group tumours are part of the gonadal stromal and sex cord tumours (GSST) and represent 1-4.7% of all organic ovarian tumours and are usually benign. We felt it important to report a case in order to share our experience in the management of fibrothecal tumours of the ovary. Observation: This was a 51-year-old postmenopausal patient who was referred to the hospital for abdominal pain in the context of an abdominal mass. A clinical examination and abdominal ultrasound concluded that the left ovarian tumour was benign. A left annecxectomy was performed and the histological examination concluded that the tumour was benign. No tumour marker was measured and no CT scan was performed. The postoperative course was simple and the patient was followed for 3 months.

Myoid Gonadal Stromal Tumor: A new Case Report with a Review of the Literature.

The myoid gonadal stromal tumor is a very rare testicular spindle cell tumor. Few cases have been reported in the literature from 1977 to 2022. It was an emerging entity in the fourth edition of the WHO Classification of Tumors of the Urinary System and Male Genital Organs and has been instated as a full benign entity in the new edition of 2022. We report herein an additional case of a myoid gonadal stromal tumor. It was a 27-year-old man who presented with an asymptomatic mass in his left testicle for 2 months. The mass was confirmed by ultrasound as a 3 cm solid well-circumscribed lesion for which orchiectomy has been performed. The histological analysis of the specimen and the immunohistochemistry staining was consistent with a myoid gonadal stromal tumor. The characteristics of this tumor are summarized in well-circumscribed, nonencapsulated masses of uniform spindle cells, and immunohistochemically, tumor cells coexpress SMA and S-100 protein. The benign behavior of this tumor is demonstrated by our results and those presented in the previous cases reported in the literature.

News in the classification of WHO 2022 testicular tumours.

The novelties in WHO 5th edition classification of genitourinary tumours are: a) nomenclature changes, including the replacement of the term "primitive neuroectodermal tumour" with "embryonic-type neuroectodermal tumour" and of "carcinoid" with "neuroendocrine tumour". Also, seminoma is now placed in a "germinoma" family of tumours, while sertoliform cystoadenoma was moved from adnexal tumours to Sertoli cell tumours; b) new entities, specifically signet ring stromal tumour, myoid gonadal stromal tumour and well-differentiated papillary mesothelial tumour.

New 2022 WHO classification of testicular tumours

The 5th edition of the WHO Classification of Tumours: Urinary and Male Genital Tumours includes some important revisions of the testicular tumour classifications, which are summarized in this article. They concern, for example, the definition of tumours of neuroectodermal and neuroendocrine origin. Furthermore, signet-ring stromal tumours and myoid gonadal stromal tumours are listed as separate entities in the section about sex-cord stromal tumours. Moreover, lymphatic neoplasia as well as soft tissue tumours of the urinary and male genital tract are each combined in acommon section.

Sex cord stromal tumors and tumors of the paratestis: new and old entities in a landscape of rare tumors.

The 5th edition of WHO classification incorporates the most relevant new data available in the literature regarding tumors of the male genitourinary tract. In this review, the authors summarize and critically discuss the most relevant new information regarding tumors occurring in the stromal testis and in the paratestis that will be reported in the new edition of WHO classification of tumors of the male genitourinary tract. Signet-ring stromal tumors (SRST) and myoid gonadal stromal tumors (MGST) are two new entities brought in the 5th WHO classification of testicular tumors. All cases of SRST and MGST reported so far have behaved in a benign fashion after resection and whenever possible a conservative surgery is recommended. A future perspective is to aim at creating large multiinstitutional case series to link different morphologic patterns and molecular bases to the biologic behavior of these neoplasms. Another innovation in WHO consists in the inclusion in the group of Sertoli cell tumors of the sertoliform cystadenoma. The sertoliform cystadenoma is localized in the rete testis and it is of unknown origin. It was included in the group of gonadal stromal tumors because of a high morphological and immunohistochemical similarity to the Sertoli cell tumor. Although further studies with long-term follow-up are needed to estimate the main oncologic outcomes in patients with rare gonadal stromal tumors, we highlight the importance of an accurate characterization by molecular and immunohistochemical assays of these entities.

An introduction to the WHO 5th edition 2022 classification of testicular tumours.

The 5th edition of the World Health Organisation Blue Book was published recently and includes a comprehensive update on testicular tumours. This builds upon the work of the 4th edition, retaining its structure and main nomenclature, including the use of the term ‘germ cell neoplasia in situ’ (GCNIS) for the pre‐invasive lesion of most germ cell tumours and division from those not derived from GCNIS. While there have been important developments in understanding the molecular underpinnings of testicular cancer, this updated classification paradigm and approach remains rooted in morphology. Nomenclature changes include replacement of the term ‘primitive neuroectodermal tumour’ by ‘embryonic neuroectodermal tumour’ based on the non‐specificity of the former term and to separate these tumours clearly from Ewing sarcoma. Seminoma is placed in a germinoma family of tumours emphasising relation to those tumours at other sites. Criteria for the diagnosis of ‘teratoma with somatic transformation’ have been modified to not include variable field size assessments. The word ‘carcinoid’ has been changed to ‘neuroendocrine tumour’, with most examples in the testis now classified as ‘prepubertal type testicular neuroendocrine tumour’. For sex cord‐stromal tumours, the use of mitotic counts per high‐power field has been changed to per mm2 for malignancy assessments, and the new entities, ‘signet ring stromal tumour’ and ‘myoid gonadal stromal tumour’, are defined. Well‐differentiated papillary mesothelial tumour has now been defined as tumour type with a favourable prognosis. Sertoliform cystadenoma has been removed as an entity from testicular adnexal tumours and placed with Sertoli cell tumours.

Myoid gonadal stromal tumor, a case report with review of the literature.

The diagnosis of myoid gonadal stromal tumor (MSGT) can represent a difficult challenge, both for the extreme rarity of this neoplasm and for the clinical-radiological characteristics similar to other neoplasms of the testicle. The case management we present suggests how a complete differential diagnosis can be obtained by integrating ultrasonographic and pathological data.

Role of Ovarian Fertility Sparing Surgery (FSS) in Cases of Early Stage 1 Ovarian Cancer in Patients in Reproductive Age Group

Objective: To assess the role of FSS in women with early stage 1 ovarian cancer. Methods: This was a retrospective analytic study of the results of treatment of 24 patients all under 40 years of age who underwent a full conservative staging laparotomy procedure in oncology center of El Shatby Maternity hospital, Alexandria University in the period of one year from October 2019 to September 2020. All patients were followed up for a six month period following surgery by the pre-operatively elevated tumor marker and by a CT abdomen and pelvis to detect any tumor recurrence. Results: The mean age at diagnosis was 24.29 Years. 6/24 (25%) of surface epithelial tumor were G1, 8/24 (33.3%) were G2, 4/24 (16.7%) were G3. 20/24 (83.3%) of patients were stage FIGO 1a, 4/25 (16.7%) were stage 1b, and none of them was stage 1c. 20/24 (83.3%) of patients were stage FIGO 1a, 4/25 (16.7%) were stage 1b, and none of them was stage 1c. Recurrence was reported in 3/24 of cases (12.5%), such 3 cases underwent unilateral SO plus a FCSLP. No recurrence was reported in cases of bilateral tumors that underwent unilateral SO and a contralateral cystectomy. 100% of recurrence was in epithelial tumors. 1/24 (4.1%) was clear cell, 1/24 (4.1%) was serous and 1/24 (4.1%) was mucinous. None of the endometroid tumors did recur. Also none of the non-epithelial tumors showed any recurrence. Tumors of G1 showed no recurrence, G2 tumors showed 33.3% recurrence and G3 tumors showed the highest recurrence rate (66.6%). Conclusion: ovarian FSS is a safe surgical option for nearly all OC patients with low risk of recurrence, with apparently early stage OC, after being confirmed by a FCSLP to exclude any occult metastasis (occult advanced stage OC), including those cases of early epithelial OC, germ cell and gonadal stromal tumors and it should be considered for patients who have a strong desire to keep their fertility.

Unclassified sex cord / gonadal stromal testis tumour with a pure spindle cell component

Incompletely differentiated sex cord / gonadal stromal tumours of the testis (SCST) of pure spindle cell morphology are extremely rare with only four reported cases in the literature.1 We report a case of a 73-year-old man who presented with acute on chronic renal failure and noted to have an enlarged tender left testicle. Ultrasound examination revealed an enlarged testis (40 cc) with diffuse heterogeneity of the testicular parenchyma. A radical orchiectomy procedure was performed. The histological examination revealed a well circumscribed tumour (55 mm in maximum diameter) comprised purely of fascicles of spindle cells with elongated to ovoid nuclei. Immunohistochemical stains demonstrated positive staining for Vimentin, S100, SMA, Inhibin, Calretinin and CD99. EMA, Cam 5.2, AE1&3, Desmin, CD34, Melan-A, HMB-45, Sox10, CD117 and PLAP stains were negative. The overall features were consistent with the diagnosis of unclassified SCSTs of pure spindle cells morphology. Due to the rarity, SCST of spindle cell morphology are under studied. They are of unknown clinical behaviour. However, they should be considered in the differential diagnosis of spindle cell lesions of the testis.

Pediatric testicular cancer: Two decades of Saudi national data.

Pediatric testicular cancer is exceedingly rare. There are no data available touching Saudi children. The aim of the study is to determine the trends and patterns of testicular cancer among Saudi children over a period of 20 years. The national database of the Saudi Cancer Registry (SCR) on pediatric testicular cancer over the last two decades was examined including epidemiological and histological patterns. From 1994 to 2013, 82 cases of testicular cancer among Saudi children aged 1–14 years were accumulated at the SCR. The annual percentage change rate was 3.3%. Of all cases, 62% appeared within the first 2 years of life. Seminomas were seen in 39%, nonseminomas in 40.3%, and paratesticular tumors in 20.7%. No gonadal stromal tumors observed. About 91% of the seminomas accrued in the first decade (1994–2003), while all nonseminomas fell in the last decade (2004–2013). The most common subtypes of the nonseminomas were yolk sac tumors and mixed tumors. More than 80% of the paratesticular tumors were rhabdomyosarcomas and lymphomas. The SEER summary stage of seminomas was localized in 56%, regional in 22%, and distant in 16%, while of nonseminomas was 56%, 16%, and 28%, respectively, and no stage improvement over the studied period was noted. No temporal trend in incidence rate was observed. The most affected age group was the first 2 years of life. Noteworthy was the high incidence of seminoma and the low rate of teratomas and stromal tumors, when compared to Western data. Notable was the dominance of the seminomas in the first decade and of the nonseminomas in the second decade. At the time of diagnosis, nonseminomas were more advanced than seminomas. No stage improvement noted over the studied period.

Flometoquin (Pesticides).

Food Safety Commission of Japan (FSCJ) conducted a risk assessment of flometoquin (CAS No. 875775-74-9), a quinoline insecticide, based on results from various studies. Major adverse effects of flometoquin observed were suppressed body weight and hepatocellular steatosis in rats, and ovarian atrophy with decreased numbers of small follicle in rats and mice. Neither teratogenicity nor genotoxicity relevant to human health was detected. Increased incidences of gonadal stromal tumor in female rats and of small intestine adenocarcinomas in male mice were identified in carcinogenicity studies. Genotoxic mechanisms were, however, unlikely involved in their tumor developments, and these enabled FSCJ to establish a threshold in the assessment. Mechanism and toxicity studies suggested that ovarian atrophy triggered the development of gonadal stromal tumor, through continuous stimulation of gonadotropin to the gonadal stroma, via negative feedback. A reproductive study showed the decreases in numbers of small follicle, implantation and also in litter size. Based on the results from various studies, flometoquin (parent compound only) was the residue definition for dietary risk assessment in agricultural products. The lowest no-observed-adverse-effect level (NOAEL) obtained from all the studies was 0.8 mg/kg bw/day in a developmental toxicity study in rabbits. FSCJ specified an acceptable daily intake (ADI) of 0.008 mg/kg bw/day by applying a safety factor of 100 to the NOAEL. FSCJ recognized that in considering the ambiguity of the underlying mechanism, the adverse effect on small follicle possibly occurred after single oral administration of flometoquin. Thus FSCJ specified an acute reference dose (ARfD) to be 0.044 mg/kg bw by applying a safety factor of 100 to the NOAEL of 4.45 mg/kg bw per day in a two-generation reproductive toxicity study in rats, based on a comprehensive evaluation of NOAEL for ovarian toxicity.

Adult testicular cancer: Two decades of Saudi national data.

There is a paucity of data regarding testicular cancer among Saudis as well as the nonexistent of published national data. Furthermore, a substantial increase of the incidence of testicular cancer among Saudis was lately noted. The aim of the study is to determine the trends and patterns of testicular cancer among adult Saudis using national data over a period of 20 years. The national database of the Saudi Cancer Registry (SCR) on testicular cancer over the last two decades was studied including epidemiological and histological patterns. The 1004 cases of testicular cancer among adult Saudis reported by the SCR will be the subject of this study. From 1994 to 2013, 1004 cases of testicular cancer among adult Saudis were reported to the SCR, with a steadily significant increase in incidence rate reaching an annual rate of 94 cases in 2013. Age of the patients ranged 15–93 years with a mean of 34.5 years. The most affected age group was 20–34 years, where 51% of all testicular cancer accumulated. Around 85% of testicular cancer is germ cell tumors, while paratesticular and gonadal stromal tumors represent 15%. Of all testicular cancer, seminomas were seen in 40.7%, nonseminomas in 44.6%. Notably, 70.4% of the cases in the first decade were seminomas, while in the second decade 65.9% of the cases were nonseminomas. The subtypes of the nonseminomas were a mixed tumor in 51.6%, embryonal carcinoma in 19.9%, yolk sac tumor in 12.3%, germinomas in 6.7%, teratomas in 6%, and choriocarcinomas in 3.6%. Lymphomas (34.7%) and rhabdomyosarcomas (23.6%) are on the top of the paratesticular tumor group. The Surveillance Epidemiology and End Results summary stage of seminomas was localized in 61.6%, regional in 19.8%, and distant in 12.6%, while of nonseminomas was 48%, 15.5%, and 28.5%, respectively. Localized and distant status of seminomas improved over the studied period by 12% and 4% respectively, while this trend was not seen in nonseminomas. The incidence rate is on rising with doubling observed during the last decade. The most affected age group was 20–34 years. Noteworthy was the dominance of the seminomas in the first decade and of the nonseminomas in the second decade. Paratesticular tumors rate is high, third of which were lymphomas. Compared to data from Western countries, notably, there is a high rate of yolk sac tumors and germinomas and a low incidence of choriocarcinomas and embryonal carcinomas. In general, late presentation of all testicular cancer was noted, although a modest stage improvement over the studied period was observed in seminomas, not in nonseminomas.

The World Health Organization 2016 classification of testicular non-germ cell tumours: a review and update from the International Society of Urological Pathology Testis Consultation Panel.

The World Health Organization (WHO) released a new tumour classification for the genitourinary system in early 2016 after consensus by pathologists with expertise in these organs. It utilized the framework of the 2004 classification, and incorporated the most up-to-date information concerning these tumours. In testicular tumours, the majority of the changes occurred in the nomenclature and classification of germ cell tumours; however, several modifications were also made for non-germ cell tumours. Among sex cord-stromal tumours, sclerosing Sertoli cell tumour (SCT) is no longer recognized as a separate entity but as a morphological variant of SCT not otherwise specified (NOS), as CTNNB1 gene mutations have been noted in both neoplasms but not in the other forms of SCT. Similarly, the lipid cell variant is not separately classified, but is considered to be a morphological variant of SCT NOS. Large-cell calcifying SCT is recognized as a distinct entity that occurs either sporadically or in association with Carney complex, with the latter patients having a distinct germline PRKAR1A gene mutation. Intratubular large-cell hyalinizing Sertoli cell neoplasia is also accepted as a separate entity linked with Peutz-Jeghers syndrome. The subcategories of 'mixed' and 'incompletely differentiated' forms of sex cord/gonadal stromal tumours have been replaced by 'mixed and unclassified sex cord-stromal tumours'. New entities introduced in the latest WHO revision include: myoid gonadal stromal tumour and 'undifferentiated gonadal tissue', a putative precursor lesion of gonadoblastoma, whereas juvenile xanthogranuloma and haemangioma are included in the miscellaneous category of tumours.

A database survey of equine tumours in the United Kingdom.

Survey data on equine tumours are sparse compared with other species and may have changed over time. To describe the most frequently diagnosed equine tumours recorded by a diagnostic pathology laboratory over 29 years, to identify background factors associated with tumour type, and to identify any changes in the tumours diagnosed or the background of cases submitted during the study period. Observational; cross-sectional analysis of records of a diagnostic pathology laboratory. The records of all neoplastic equine histology submissions to the University of Bristol (January 1982-December 2010) were accessed from a database, and a list of diagnoses compiled. The 6 most commonly diagnosed tumour types were analysed using logistic regression to identify background factors associated with tumour type. The overall population of equine tumour submissions and the relative frequency of diagnosis of the most common tumour types were compared between decades. There were 964 cases included. The most frequently diagnosed tumours were: sarcoid (24% cases), squamous cell carcinoma (SCC) (19%), lymphoma (14%), melanoma (6%), gonadal stromal tumour (6%) and mast cell tumour (MCT) (4%). With sarcoid, Thoroughbred/Thoroughbred cross and gelding as reference categories: increasing age was significantly associated with the odds of each of the other tumour types, mares were at reduced risk of SCC, Arab/Arab cross had a higher risk of MCT, Cob/Cob cross had an increased risk of SCC and MCT, and ponies had an increased risk of melanoma. The mean age of submissions increased in each successive decade and the breed composition became broader. Sarcoids and lymphoma formed a smaller proportion of diagnoses in later decades. The types of tumours submitted to this laboratory have changed over the last 3 decades. Current data inform clinicians and researchers and further studies are warranted to follow trends.

Primary cystic peritoneal masses and mimickers: spectrum of diseases with pathologic correlation.

Cystic lesions within the peritoneum have been classified classically according to their lining on histology into four categories-endothelial, epithelial, mesothelial, and others (germ cell tumors, sex cord gonadal stromal tumors, cystic mesenchymal tumors, fibrous wall tumors, and infectious cystic peritoneal lesions). In this article, we will proceed to classify cystic peritoneal lesions focusing on the degree of radiological complexity into three categories-simple cystic, mildly complex, and cystic with solid component lesions. Many intra-abdominal collections within the peritoneal cavity such as abscess, seroma, biloma, urinoma, or lymphocele may mimic primary peritoneal cystic masses and need to be differentiated. Clinical history and imaging features may help differentiate intra-abdominal collections from primary peritoneal masses. Lymphangiomas are benign multilocular cystic masses that can virtually occur in any location within the abdomen and insinuate between structures. Ultrasound may help differentiate enteric duplication cysts from other mesenteric and omental cysts in the abdomen. Double-layered wall along the mesenteric side of bowel may suggest its diagnosis in the proper clinical setting. Characteristic imaging features of hydatid cysts are internal daughter cysts, floating membranes and matrix, peripheral calcifications, and collagenous pericyst. Non-pancreatic psuedocysts usually have a fibrotic thick wall and chylous content may lead to a fat-fluid level. Pseudomyxoma peritonei appears as loculated fluid collections in the peritoneal cavity, omentum, and mesentery and may scallop visceral surfaces. Many of the primary cystic peritoneal masses have specific imaging features which can help in accurate diagnosis and management of these entities. Knowledge of the imaging spectrum of cystic peritoneal masses is necessary to distinguish from other potential cystic abdominal mimicker masses.

Sex cord gonadal stromal tumors

According to the World Health Organization (WHO) classification from 2004, sex cord gonadal stromal tumors are divided into Leydig cell tumors, Sertoli cell tumors, granulosa cell tumors, tumors of the thecoma-fibroma group, incompletely differentiated sex cord gonadal stromal tumors, mixed forms of sex cord gonadal stromal tumors and tumors containing both germ cell and sex cord gonadal stromal elements. These tumors can appear sporadically or in combination with hereditary syndromes. To diagnose these rare tumors the combination of characteristic morphological aspects and various immunohistochemical markers is useful. Latest investigations demonstrate the potential role of mutation analyses in the diagnosis of this heterogeneous group of tumors.