Primitive Embryonic-Type Neuroectodermal/Glandular Complexes in Testicular Germ Cell Tumors: A Mimic of Embryonic-Type Neuroectodermal Tumor.

Embryonic-type neuroectodermal elements are often intimately mixed with primitive endodermal-type glands, like those of yolk sac tumors, in germ cell neoplasia in situ (GCNIS)-derived germ cell tumors of the testis. Because the primitive glands mimic tubules or rosettes of embryonic-type neuroectodermal elements, these embryonic-type neuroectodermal/glandular complexes may be misinterpreted as pure lesions of embryonic-type neuroectodermal elements, which, if of sufficient size, may lead to a diagnosis of embryonic-type neuroectodermal tumor, despite that the criteria of the World Health Organization for a "somatic-type malignancy" are not met. A diagnosis of embryonic-type neuroectodermal tumor in the testis may lead to retroperitoneal lymphadenectomy even in clinical stage I patients, and in postchemotherapy resections indicates a poor prognosis. The distinction of the neuroectodermal and glandular elements is not always straightforward based on morphology alone. We, therefore, studied 34 testis-derived germ cell tumors with embryonic-type neuroectodermal/glandular complexes and 2 purely glandular yolk sac tumors to characterize the immunophenotypes and determine an efficient immunohistochemical panel to aid in this differential. We found that GFAP, synaptophysin, and paired-like homeobox 2B (PHOX2B) expression was specific to embryonic-type neuroectodermal elements, although PHOX2B had poor sensitivity. In contrast, positive reactions with antibodies directed against AFP, villin, and CDX2 were specific for the glandular elements, although CDX2 had poor sensitivity. Other markers, including AE1/AE3 cytokeratin, SALL4, glypican 3, SOX2, SOX11, CD56, INSM1, and neurofilament, proved less helpful because of their nonspecificity and/or poor sensitivity. We conclude that the optimal immunohistochemical panel for distinguishing the components of embryonic-type neuroectodermal/glandular complexes includes stains for synaptophysin, GFAP, villin, and AFP.

Yolk Sac Differentiation in Endometrial Carcinoma: Incidence and Clinicopathologic Features of Somatically Derived Yolk Sac Tumors Versus Carcinomas With Nonspecific Immunoexpression of Yolk Sac Markers.

Endometrial somatically derived yolk sac tumors are characterized by yolk sac morphology with AFP, SALL-4, and/or Glypican-3 immunoexpression. Yolk sac marker expression, however, is not limited to tumors with overt yolk sac histology. Three hundred consecutive endometrial malignancies were assessed for immunomarkers of yolk sac differentiation. Of these, 9% expressed ≥1 yolk sac marker, including 29% of high-grade tumors. Only 3 (1%) met morphologic criteria for yolk sac differentiation; these were originally diagnosed as serous, high-grade NOS, and dedifferentiated carcinoma. Two were MMR-intact and comprised exclusively of yolk sac elements, while the dedifferentiated case was MMR deficient and had a background low-grade endometrioid carcinoma; this case also showed BRG1 loss. All 3 were INI1 intact. Nonspecific yolk sac marker expression was seen in 14 carcinosarcomas, 4 endometrioid, 2 serous, 1 clear cell, 1 dedifferentiated, 1 mixed serous/clear cell, and 1 mesonephric-like carcinoma. INI1 was intact in all cases; one showed BRG1 loss. Twenty were MMR-intact, and 4 were MMR deficient. All MMR-deficient cases with yolk sac marker expression, both with and without true yolk sac morphology, had no evidence of residual disease on follow-up, whereas 82% of MMR-intact cases developed recurrent/metastatic disease. In summary, endometrial somatically derived yolk sac tumors were rare but under-recognized. While AFP immunostaining was specific for this diagnosis, Glypican-3 and SALL-4 expression was seen in a variety of other high-grade carcinomas. INI1 loss was not associated with yolk sac morphology or immunomarker expression in the endometrium, and BRG1 loss was rare. All patients with MMR-deficient carcinomas with yolk sac immunoexpression +/- morphology were disease-free on follow-up, whereas the majority of MMR-intact cancers showed aggressive disease.

Extensive surgical resections for rare pleural neoplasms: a single-center experience with a yolk sac tumor and synovial sarcoma.

BACKGROUND: Pleural neoplasms are rare and can be subdivided into pleural metastasis and primary pleural neoplasms. Non-mesothelioma primary pleural neoplasms are a diverse group of extremely rare pathologies. CASE PRESENTATION: In this case series, we describe the presentation and management of two rare primary pleural neoplasms. A first case describes a primary pleural yolk sac tumor treated with neoadjuvant chemotherapy, extended pleurectomy decortication, and hyperthermic intrathoracic chemotherapy. In a second case we describe the management of a primary pleural synovial sarcoma by neoadjuvant chemotherapy and extrapleural pneumonectomy. A complete resection was obtained in both cases and the post-operative course was uncomplicated. No signs of tumor recurrence were noted during follow-up in the first patient. In the second patient a local recurrence was diagnosed 6 months after surgery. CONCLUSION: Neo-adjuvant chemotherapy followed by extensive thoracic surgery, including hyperthermic intrathoracic chemotherapy, is a feasible treatment strategy for non-mesothelioma primary pleural neoplasms, but careful follow-up is required.

[Clinical analysis of 12 cases of ovarian yolk sac tumor].

Objective: To investigate the diagnosis, treatment and prognosis of ovarian yolk sac tumor (OYST). Methods: The clinicopathological data and follow-up data of 12 patients with OYST admitted to the Affiliated Hospital of Qingdao University from January 2013 to December 2020 were retrospectively analyzed, and the diagnosis, treatment and prognosis of OYST patients were summarized. Results: (1) The age of 12 patients with OYST ranged from 11 to 37 years, with a median age of 20 years. At the first visit, all 12 patients had pelvic masses. Reasons for seeing a doctor: 6 cases of abdominal distension and abdominal pain, 4 cases of mass in the lower abdomen, 1 case of vaginal bleeding, and 1 case of appendicitis. International Federation of Obstetrics and Gynecology (FIGO) 2014 staging: 4 cases in stage Ⅰa, 2 cases in stage Ⅰc, 1 case in stage Ⅱc, 4 cases in stage Ⅲc, and 1 case in stage Ⅳb. (2) All 12 patients were examined by color Doppler ultrasound before operation, among which 10 cases showed unilateral adnexal masses and 2 cases bilateral adnexal masses. The median maximum diameter of tumor was 16.5 cm (range: 6.0-28.0 cm). The preoperative levels of alpha fetoprotein (AFP) in 12 patients (all >1 210 µg/L) were significantly higher than normal (<25 µg/L). Among the 11 patients with cancer antigen 125 (CA125) detection results, 9 patients showed elevated serum CA125 levels. (3) Among the 12 patients, 8 young infertile patients who needed to preserve their reproductive function underwent appendectomy, 3 infertile patients underwent staged surgery for ovarian malignant germ cell tumor, and only one bilateral lesion and infertile patient underwent unsatisfactory staged surgery for ovarian malignant germ cell tumor. Of the 12 patients, 11 patients were given combined chemotherapy regimen of bleomycin, cisplatin, and etoposide (BEP) after operation. One patient without chemotherapy developed metastasis 3 months after operation, and was given BEP chemotherapy, and her condition was controlled. (4) The deadline for follow-up was December 31st, 2022, and the median follow-up time was 60 months (range: 25-115 months). All the 12 patients survived without tumor during the follow-up period, and the median disease-free survival time was 84.5 months (range: 25-115 months). Conclusions: OYST mostly occurs in children and young women. Color Doppler ultrasound examination and serum AFP and CA125 detection have diagnostic value for OYST. Surgical treatment after diagnosis of OYST includes surgery to preserve reproductive function and timely and standardized chemotherapy after operation. The prognosis of patients is good regardless of stage.

Survival difference among adult and pediatric mediastinal yolk sac tumors cases: A meta-analysis of case reports.

BACKGROUND: Mediastinal Yolk sac tumors (YST) are rare and highly malignant extragonadal germ cell tumors with rapid growth and early metastases. We sought to conduct a meta-analysis of published case reports/case series to compare differences in survival, demographics, and treatment modalities between adult and pediatric patients with YST. METHODS: Ovid Embase, Cochrane, and Ovid Medline databases were searched for primary mediastinal pure YST cases. The primary outcome was overall survival (OS). Log-rank and Cox regression were used. This study is registered on PROSPERO (CRD42022367586). RESULTS: Among 846 studies, 87 met our inclusion criteria including 130 patients (Adults: 90 and Pediatrics: 40). About 41.5% of the patients were from the United States. The median age was 23.0 (Q1-Q3: 17.0-30.0), 88.5% were males, and (32.3%) were Asian. Stage II represented almost 40%. AFP was elevated in 96.9%. Respiratory distress was the presenting symptom in 65.4%. Chemotherapy, radiotherapy, and surgery were utilized in 84.6, 23.1, and 64.7% respectively. Median OS was 24 months (Adults: 23 months, Pediatrics: 25 months, P = 0.89). 3- and 5-year OS were 34.4% and 22.9% in adults and 41.5% and 41.5% in pediatrics, respectively. On multivariate analysis, anterior location of tumors, receipt of chemotherapy, and undergoing surgery were associated with better OS. CONCLUSION: Primary mediastinal YSTs are rare, but lethal neoplasms. Our meta-analysis showed that mediastinal YSTs mimic other non-seminomatous mediastinal GCTs in terms of clinical characteristics and available treatment options. Early diagnosis, neoadjuvant chemotherapy, and surgical resection are the key points for effective management and improved outcomes.

Testicular Mixed Teratoma and Yolk Sac Tumor, Prepubertal Type: A Case Report with Summary of Prior Published Cases.

BACKGROUND: Testicular mixed germ cell tumor is common in the post-pubertal age, less so in prepuberty. There are only 3 reports of prepubertal mixed teratoma and yolk sac tumor. Two of these cases had immature teratoma component and were in the neonatal age group. The third case in a toddler had a mature teratoma component. CASE REPORT: An 18-month-old boy presented with a testicular mass. Serum AFP was elevated (2200 ng/ml). The orchidectomy specimen contained a yolk-sac tumor and a small epidermoid cyst, indicating a mature teratomatous component. CONCLUSION: We report a testicular mixed teratoma and yolk sac tumor, prepubertal type along with summary of prior published cases. There is only one report describing this combination of mature teratoma with yolk sac tumor in the prepubertal testis.

Analysis of GATA3 and FOXA2 expression suggests that downregulation of genes involved in the maintenance of a mature yolk sac tumor phenotype may underlie sarcomatoid transformation.

In the post-chemotherapy setting, germ cell tumors of the testis (GCTT) that resemble non-specific sarcomas and co-express cytokeratins and glypican-3 (GPC3) are diagnosed as "sarcomatoid yolk sac tumor postpubertal-type (YSTpt)". The diagnosis of sarcomatoid YSTpt is clinically relevant but challenging due to its rarity, non-specific histology, and negative α-fetoprotein (AFP) staining. Recently, FOXA2 has emerged as a key-gene in the reprogramming of GCTT (activating the transcription of several genes, among which GATA3), and immunohistochemical studies showed that GATA3 and FOXA2 have a higher sensitivity for non-sarcomatoid YSTpt than GPC3 and AFP. We found that sarcomatoid YSTpt did not express FOXA2 [0: 14/14 (100%)] and showed focal expression of GATA3 [0: 12/14 (85.7%), 1 + : 2/14 (14.3%)], thus suggesting that these markers are not useful in diagnosing this tumor. Furthermore, we proposed a potential mechanism of sarcomatoid transformation in the post-chemotherapy setting of GCTT, mediated by the downregulation of FOXA2 and GATA3.

Liver transplantation for advanced-stage primary hepatic yolk sac tumor: A case report and literature review.

RATIONALE: Primary hepatic yolk sac tumors (YSTs) are rare in adults. Liver resection is an acknowledged treatment modality for primary hepatic YST. Liver transplantation may offer a possible cure for unresectable cases. PATIENT CONCERNS: We present a case of a 31-year-old woman with an abdominal mass who had abnormally elevated alpha-fetoprotein (AFP) levels (31,132 ng/mL; normal: 0-7 ng/mL). Contrast-enhanced computed tomography (CT) revealed large tumors located in both lobes of the liver, with arterial enhancement and venous washout. Fluorine-18 fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/CT indicated increased 18F-FDG uptake (maximum standardized uptake value, 24.4) in the liver tumors and left middle intra-abdominal nodule. DIAGNOSES: The diagnosis was primary hepatic YST with metastasis to the greater omentum. INTERVENTIONS: The patient underwent orthotopic liver transplantation and intra-abdominal nodule resection after transarterial chemoembolization (TACE) as a bridge. Intraoperatively, an intra-abdominal nodule was confirmed in the greater omentum. Histopathological examination of the liver tumors revealed Schiller-Duval bodies. The tropomyosin receptor kinase (TRK) inhibitor larotrectinib was administered, followed by four cycles of chemotherapy with bleomycin, etoposide, and cisplatin based on the next-generation sequencing results. OUTCOMES: The AFP level decreased to within the normal range. No evidence of tumor collapse was observed during the 34-month follow-up period. LESSONS: This case suggests that multimodal therapy dominated by liver transplantation, including preoperative TACE, postoperative adjuvant chemotherapy, and TRK inhibitors, is an effective treatment modality for unresectable primary hepatic YST.

Retroperitoneal yolk sac tumour encroaching the liver and adrenal gland with tumour thrombus in cavo-atrial region and hepatic veins.

Paediatric germ cell tumours (GCT) are rare tumours and are unique because of varied clinical presentation and locations. Yolk sac tumour is the predominant malignant histology and a serum marker; alpha fetoprotein is used to see treatment response and recurrent disease. It is extremely rare to find a retroperitoneal GCT with tumour thrombus extending up to the cavo-atrial region with involvement of the hepatic veins. We report a case of retroperitoneal yolk sac tumour (RPYST) with extension to the liver and right adrenal gland along with tumour thrombus in the inferior vena cava and in the right and middle hepatic veins. The child was operated after satisfactory response to chemotherapy. Excision of the tumour along with the right adrenal gland and around 5 cm of retro-hepatic caval resection was done. Inferior vena cava resection was tolerated without reconstruction. Currently child is disease-free and symptom-free at 22 months of follow-up with normal serum marker.

Administration of a glypican-3 peptide increases the infiltration and cytotoxicity of CD8+ T cells against testicular yolk sac tumor, associated with enhancing the intratumoral cGAS/STING signaling.

BACKGROUND: Glypican-3 (GPC3) is highly expressed in testicular yolk sac tumor (TYST). GPC3 has been evaluated as a cancer vaccine for some types of tumors, but little is known on the effects of GPC3 peptide-based therapy on TYST. Here, we evaluated the antitumor effect of GPC3144-152 on TYST and its potential mechanisms. METHODS: GPC3144-152 -specific CD8+ T cells were induced by vaccine immunization and examined by ELISPOT. The CD8+ T cells were purified for testing their cytotoxicity in vitro against TYST cells by CCK-8 and TUNEL assays and in vivo against tumor growth. The influence of GPC3144-152 loading and/or cGAS silencing on the tumor growth, apoptosis and cGAS/STING signaling was tested by immunohistochemistry, immunofluorescence, flow cytometry, and Western blot. RESULTS: Vaccination with GPC3144-152 induced tumor-specific CD8+ T cells that secreted high levels of IFN-γ and granzyme B, and had potent cytotoxicity against TYST in a dose-dependent manner. Adoptive transfer of CD8+ T cells and treatment with GPC3144-152 significantly inhibited the growth of TYST tumors, but less effective for cGAS-silenced TYST tumors in vivo. Treatment with GPC3144-152 enhanced the infiltration of CD8+ T cells into the tumor environment and their cytotoxicity against TYST tumors in vivo by up-regulating granzyme B and IFN-ß expression, but down-regulating GPC3 expression in the tumors. Co-culture of CD8+ T cells with TYST in the presence of exogenous GPC3144-152 enhanced peptide-specific CD8+ T-cell cytotoxicity in vitro, accompanied by enhancing cGAS, γH2AX, TBK1, and IRF3 phosphorylation in TYST cells, but less effective in cGAS-silenced TYST cells. CONCLUSIONS: These data indicated that GPC3 peptide-specific CD8+ T cells had potent antitumor activity against TYST tumor, particularly for combined treatment with the peptide, which was partially dependent on the intratumoral cGAS/STNG signaling. GPC3 peptide vaccine may be valuable for the combination treatment of TYST.

Survival outcomes and establishment of a novel risk stratification system in patients with ovarian yolk sac tumors.

OBJECTIVE: To evaluate the survival outcomes and establish a risk stratification system in patients with ovarian yolk sac tumors (OYST). METHODS: The recurrence-free survival (RFS), disease-specific survival (DSS), and prognostic factors were retrospectively evaluated in 151 OYST patients treated in our hospital between 2006 and 2022. A risk stratification system based on the identified prognostic factors was established. RESULTS: The median follow-up time was 5.1 years, with a 5-year RFS and DSS rate of 75.5% and 91.2%, respectively. FIGO stage III-IV and the interval between treatment and normalization of AFP were two prognostic predictors. Significant differences in RFS and DSS (both P < 0.001) were identified between patients who had normalized AFP ≤ 3 and ≥ 4 cycles of chemotherapy, or among patients who had normalized AFP after ≤2, 3-4, and ≥ 5 cycles of chemotherapy. FIGO stage I - II and stage III-IV were scored as 0 and 2, respectively. AFP normalization ≤2, 3, 4, and ≥ 5 cycles of chemotherapy were scored as 0, 1, 2, and 4, respectively. A total score of 0-1, 2-3, and ≥ 4 were stratified patients into low-risk (96 patients), intermediate-risk (35 patients), and high-risk groups (20 patients), respectively. Patients in three risk stratifications manifested significant differences in both RFS and DSS (P < 0.0001). CONCLUSION: This risk stratification system based on tumor stage and the interval between treatment and normalization of AFP may help to guide clinical management by dividing OYST patients into three risk groups.

Clinical characteristics and prognostic models of gonadal and extra-gonadal yolk sac tumors: a population-based analysis in children and adolescents.

PURPOSE: Yolk sac tumors (YST) are a rare and aggressive germ cell tumor. We aimed to conduct a population-based cohort study and develop a nomogram to predict overall survival (OS) in pediatric patients with YST. METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was used to identify all pediatric patients with YST diagnosed between 2000 and 2018. The log-rank test was used to compare survival curves. To examine the impact of each factor on overall survival, a multivariate Cox proportional hazards model was created. Based on the results of the Cox regression model, a nomogram was constructed. RESULTS: A total of 520 YST patients were identified. Overall survival rates for all patients were 92.2% at 3-year and 90.3% at 5-year, respectively. The outcome of Cox proportional hazard regression revealed that age, gender, primary sites, and treatment regimens were important independent predictors in this model. Based on the Cox regression model, we created a nomogram for predicting OS in pediatric YST patients. The chance of death increased with age in patients. Furthermore, patients with extra-gonadal YST have a lower survival rate than those with gonadal YST. CONCLUSIONS: Our study revealed that age, gender, and primary site were found to be the most important predictors of the overall survival of pediatric YST, providing crucial epidemiological information for clinical management.

Primary orbital yolk sac tumor in an infant: A rare entity.

We report a case of pure orbital yolk sac tumor (YST) in an 11-month-old infant, which is a rare entity. The child presented with progressive painless swelling of the right eye and on examination had proptosis, chemosis, and lid edema. Systemic examination was within normal limits. Magnetic resonance imaging (MRI) orbit revealed a lobulated heterogeneously enhancing right retroocular mass extending up to the orbital apex, displacing the optic nerve and eroding the medial orbital wall. Biopsy of the lesion revealed pure YST histology. Serum alpha-fetoprotein (AFP) was markedly raised at 76900 ng/mL. She was started on infant bleomycin etoposide cisplatin (BEP) chemotherapy protocol. There was a good clinical and radiological response. A high index of malignancy is required in young children presenting with orbital proptosis. A multidisciplinary approach and early intervention are essential to save both vision and life.