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.

[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.

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.

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.

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.

Yolk Sac Tumour Arising in the Glans Penis an Achondroplasic Child: A Case Report with Summary of Prior Published Cases.

BACKGROUND: Yolk sac tumors (YST) are commonly encountered gonadal germ cell tumors in children, especially in the prepubertal age group. In addition to gonadal primary, it can occur in multiple extragonadal sites, of which sacrococcygeal, retroperitoneum, gastric and mediastinum are the commonest. There are 4 previous reports of primary penile YST. CASE REPORT: We describe a primary penile yolk sac tumor in a child with achondroplasia. CONCLUSION: Yolk sac tumor can occur in the penis during the prepubertal period. Penile yolk sac tumor associated with achondroplasia has not been previously reported, but this could be incidental.

FoxA2 is a reliable marker for the diagnosis of yolk sac tumour postpubertal-type.

AIMS: Yolk sac tumour postpubertal-type (YSTpt) shows a wide range of histological patterns and is challenging to diagnose. Recently, forkhead box transcription factor A2 (FoxA2) emerged as a driver of YSTpt formation and a promising marker for diagnosing YSTpt. However, FoxA2 has not been tested in the different patterns of YSTpt. This study aimed to assess the staining pattern of FoxA2 in te different patterns of YSTpt and other germ cell tumours of the testis (GCTT), comparing it with glypican-3 (GPC3) and α-fetoprotein (AFP). METHODS AND RESULTS: FOXA2, GPC3 and AFP immunohistochemistry was performed on 24 YSTpt (24 microcystic/reticular, 10 myxoid, two macrocystic, five glandular/alveolar, two endodermal sinus/perivascular, four solid, two polyembryoma/embryoid body and two polyvesicular vitelline) and 81 other GCTT. The percentage of positive cells (0, 1+, 2+, 3+) and the intensity (0, 1, 2, 3) were evaluated regardless of and within each YSTpt pattern. FoxA2 was positive in all YSTpt (24 of 24) and all but one (23 of 24) exhibited 2+/3+ stain, with higher intensity [median value (mv): 2.6] than AFP (1.8) and GPC3 (2.5). Both FoxA2 and GPC3 were positive in all microcystic/reticular (24 of 24), myxoid (10 of 10), macrocystic (two of two), endodermal sinus/perivascular (four of four) and polyembryoma/embryoid body (two of two) patterns. Nevertheless, only FoxA2 was positive in all glandular/alveolar (five of five), solid (four of four) and polyvesicular vitelline (two of two) patterns. The intensity of FoxA2 was higher than AFP and GPC3 in almost all YST patterns. In the other GCTT, FoxA2 was positive only in teratoma postpubertal-type (Tpt) [13 of 20 (65%)], with staining almost exclusively confined to the mature gastrointestinal/respiratory tract epithelium. CONCLUSIONS: FoxA2 is a highly sensitive and specific biomarker that supports the diagnosis of YSTpt. FoxA2 is superior to GPC3 and AFP, especially in rare and difficult-to-diagnose histological patterns of YSTpt, but mature glands of Tpt could represent a potential diagnostic pitfall.

Pure primary renal yolk sac tumour in an adult: extremely rare clinical finding.

We present a rare case of an extragonadal retroperitoneal yolk sac tumour in an adult male, who presented with severe abdominal pain to his local hospital. Imaging revealed a large retroperitoneal soft tissue mass with no evidence of metastases. Initial biopsy demonstrated poorly differentiated carcinoma, favoured to be renal cell carcinoma. The patient underwent surgical resection following re-presentation with severe abdominal pain and significant interval enlargement of the mass. Laparotomy revealed a renal tumour that had ruptured through the left mesocolon into the peritoneal cavity. Postoperative histopathological examination revealed a yolk sac tumour involving the kidney, perinephric fat, renal sinus fat, renal hilar lymph node and colonic mesentery. Immunohistochemical staining for alpha-fetoprotein and glypican 3 was positive in the tumour cells without evidence of other germ cell elements, confirming the diagnosis of a pure yolk sac tumour. To our knowledge, this is an extremely rare case of a primary pure yolk sac tumour arising from the kidney in an adult.

Encounter with Huge Yolk Sac Ovarian Tumor in a Child: A Case Report.

Yolk sac tumour frequently arises in the gonads as a type of germ cell tumour, though rare is a highly malignant ovarian tumour in children and prompt treatment should be done. We hereby report a case of malignant ovarian tumour presenting with an abdominal lump and increased urinary frequency. Different diagnostic modalities were used such as ultrasonography of the whole abdomen, contrast-enhanced computed tomography abdomen pelvis and tumour markers of beta-human chorionic gonadotropin and alpha-fetoprotein. This revealed an 18.2x14.3x10 cm mass likely a neoplastic germ cell tumour with minimal ascites. A tumour mass was found to arise from the left ovary and complete excision of the tumour along the left fallopian tube was done. Adjuvant chemotherapy started immediately. We hereby present a case of a 9-year-old girl with a huge yolk sac tumour of the left ovary which is rare in our setting and is presented here to differentiate any ovarian mass in this age group. Keywords: children; surgical procedure; yolk sac tumour.

Primary Pediatric Yolk Sac Tumor of Liver With Lung Metastasis: An Unusual Presentation With Diagnosis Aided by LIN28 Immunohistochemistry.

Yolk sac tumor is a malignant germ cell tumor, which typically occurs in the gonads with elevated serum alpha-fetoprotein (AFP). Among extragonadal sites, the liver is an uncommon location for primary pediatric yolk sac tumors. Other common hepatic tumors in this age group presenting with elevated serum AFP like hepatoblastoma and hepatocellular carcinoma must be differentiated from yolk sac tumors for initiating appropriate treatment and accurate prognostication. Lung metastasis with refractoriness to chemotherapy is an extraordinary presentation that has never been documented in the literature. We report our experience with a 2-year-old female child initially misdiagnosed as hepatoblastoma. It was found that LIN28 positivity by immunohistochemistry aided in confirmation of the histopathological diagnosis of primary yolk sac tumor of the liver.

Renal Yolk Sac Tumor Clinically Misdiagnosed as Nephroblastoma: A Case Report.

Background: Yolk sac tumor is a germ cell tumor (GCT) that occurs in infants and adolescents and affects various sites. There is a trend to treat pediatric renal tumors before a tissue diagnosis. We report a renal yolk sac tumor clinically misdiagnosed as Wilms tumor, based on ultrasound (US) and MRI.Case Report: This 21-month-old male infant was discovered to have a space occupying lesion in the right kidney. Because the tumor was large, initial radiotherapy preceded surgical resection. Histologically, the tumor was a yolk sac tumor.Conclusion: Imaging examination of renal yolk sac tumor can easily be misdiagnosed as Wilms tumor. SIOP treatment plan for Wilms tumor requires preoperative chemotherapy, which is different from the treatment regimen for yolk sac tumor. Preoperative alpha-fetoprotein could have been helpful in avoiding this clinical misdiagnosis.

Primary Pure Intrarenal Yolk Sac Tumor in 1.5-Year-Old Boy-A Rare Case Report.

Germ cell tumors primarily arise in gonads and extragonadal germ cell tumors, an uncommon entity, originates usually along the midline. Here, we report the fifth example of intrarenal pure yolk sac tumor in a 1.5-year-old boy who presented with abdominal pain and underwent excision of the mass for suspected Wilms tumor. On histopathology and immunohistochemistry, a diagnosis of a yolk sac tumor was rendered. Postoperative serum alpha-fetoprotein levels were 21 000 ng/dl. The purpose of this report is to emphasize the importance of suspecting a germ cell tumor as one of the differential diagnoses of a suspected case of Wilms tumor and the significance of evaluating serum alpha-fetoprotein levels preoperatively.

Ovarian yolk sac tumor in a premenarchal girl.

Yolk sac tumors are highly malignant and commonly affect the ovaries, with a median age of occurrence of 23 years. We describe the case of an ovarian yolk sac tumor in a 12-year-old premenarchal girl suffering from Hashimoto's thyroiditis and chronic spontaneous urticaria, which presented as a rapidly growing solid cystic formation in the hypogastrium with an extreme increase in alpha fetoprotein (52,778 mg/ml). After ultrasound and MRI imaging, fertility-sparing staging surgery was performed, and the diagnosis of an ovarian yolk sac tumor with positive malignant cells in ascites was confirmed. The specificity of this case is the tumor classification into stage IC3 according to the FIGO and stage III according to the Children's Oncology Group criteria. The postoperative course was complicated by a pelvic abscess and a subcutaneous suture rejection reaction. Our case may incite further research on the relationship between autoimmunity and yolk sac tumors.

Pediatric Primary Yolk Sac Tumour of the Kidney: Recommendations for Pretreatment Diagnosis.

Introduction Although nephroblastomas are frequently treated without prior biopsy, there are the occasional other pediatric renal tumors that require different management. In the literature, there are around 30 primary renal germ cell tumors (GCT), including four cases of Yolk sac tumor (YST). We present another primary renal YST.Case report: A five-year-old boy was diagnosed as Wilms tumor on radiology and needle biopsy. He received chemotherapy, with no response. The post-chemotherapy resection specimen revealed a YST.Conclusion: Renal YST may be indistinguishable from Wilms tumor clinically and radiologically. For pre-biopsy chemotherapy management protocols, serum tumor markers such as AFP may be recommended to identify the occasional GCT, including YST. Pre-chemotherapy needle biopsies may lead to misdiagnosis, and may require confirmation by an experienced pathologist or central review.

Alpha-Fetoprotein-Producing Esophageal Adenocarcinoma With Enteroblastic, Yolk Sac Tumor-Like, and Hepatoid Carcinoma Differentiation: A Rare Case and Literature Review.

We report a case of a 65-year-old man with alpha-fetoprotein (AFP)-producing esophageal adenocarcinoma that microscopically consisted of a polymorphous blend of enteroblastic, yolk sac-like, and hepatoid carcinoma components of variable proportions. No histological evidence of Barrett's esophagus was identified. Two weeks post-endoscopic mucosal mass resection, the serum AFP level was 1434.6 ng/mL. The patient underwent radiation and chemotherapy but developed metastatic lung lesions. At 18 months post-resection, the patient is alive. AFP-producing esophageal adenocarcinoma is a rare entity. We reviewed reported cases for clinicopathological features, treatment strategies, and prognosis.

Ovarian Mucinous Carcinoma with a Yolk sac Tumor-Like Component: A Report of Three Cases with a Literature Review for Prognostic Analysis.

The most common subtype of ovarian carcinoma associated with somatically derived yolk sac tumor (YST) is endometrioid carcinoma. Only two cases of ovarian mucinous carcinomas associated with YST have been reported; herein, we present three additional patients, along with a review of previous literature and our pathology archives to analyze the tumor prognosis. The patients' ages ranged from 38 to 53 years. Two patients had FIGO stage 1 tumors, and one patient had a stage 3 tumor. Two patients died of the disease within a year, and one patient survived with distant metastasis (32 months after surgery). In all three tumors, the YST-like component comprised less than 5% of the total tumor area. Together with the two previously reported mucinous carcinomas with a YST-like component, the prognosis of the five mucinous carcinomas with a YST-like component were compared with that of 19 conventional mucinous carcinomas resected at our hospital. The survival curves were estimated using the Kaplan-Meier method. As a result, the overall survival rate of patients with mucinous carcinomas with a YST-like component was significantly lower than that of patients with conventional mucinous carcinomas (P = .0014). Our study indicates that the presence of a YST-like component in mucinous carcinomas would be a strong prognostic indicator.

Mixed Germ Cell Tumor with a Yolk Sac Tumor Component in the Medulla Oblongata of a 50-year-old Patient: A Case Report and Literature Review.

Yolk sac tumor (YST) is a rare primary brain tumor that occurs almost exclusively in patients under 30 years old. Intracranial germ cell tumors are most frequently located in the pineal and suprasellar region. Medulla oblongata YSTs are particularly rare. Extragonadal YSTs may be difficult to diagnose because of their characteristics, such as the rarity and variety of growth patterns. Furthermore, they are known to have a very poor prognosis. We herein report a case of YST of the medulla oblongata in a 50-year-old woman. She was followed up for 18 months without any tumor recurrence.

[Diagnostic problems in testicular tumours in consultant pathology : A practical guide]. / Diagnostische Probleme bei Hodentumoren in der Konsiliarpathologie : Ein praktischer Leitfaden.

The great variety of pathological patterns in germ cell tumours, especially in yolk sac tumours but also the possibility of somatic-type malignancies, can complicate daily diagnosis. For the correct diagnosis, knowledge of morphological aspects and additional immunohistochemical staining can be helpful. Also, rare entities like sex cord stromal tumours, tumours of testicular adnexa or mesenchymal tumours of the spermatic cord can be diagnostically challenging.