Yolk Sac Tumor in Postmenopausal Patients: Pure or Associated With Adenocarcinoma, a Rare Phenomenon

Molecular Evidence for Epithelial Origin of Mixed Ovarian Epithelial-Germ Cell Neoplasms: Report of 2 Cases and Review of Literature

Ovarian germ cell tumors (GCT) account for 2% to 3% of malignant ovarian neoplasms in Western countries and typically occur within the first 2 decades. When presenting later in life, GCTs may be associated with epithelial malignancies. In these circumstances, it has been theorized that these tumors may originate from a somatic, rather than germ cell origin, especially in the postmenopausal setting; however, the true derivation is not fully understood. Our database was searched for primary ovarian GCTs associated with a malignant epithelial component in patients above 35 yr of age, from 2006 to 2021. Two cases were identified and in each case, slides were reviewed and targeted next-generation sequencing was utilized to identify and compare gene mutation variants in morphologically distinct components. Patient A is a 58-yr-old, with choriocarcinoma and minor component of mucinous adenocarcinoma, and patient B is a 43-yr-old, with yolk sac tumor and minor component of endometrioid adenocarcinoma. The morphologically distinct areas in each case showed disparate staining patterns; however, next-generation sequencing demonstrated identical mutation variants within both the germ cell and epithelial components. Variants in CDKN2A , PIK3CA , PIK3R1 , and TP53 were present in patient A's tumor, while patient B's tumor showed CTNNB1 , PIK3R1 , and 2 PTEN variants. These mutational patterns are similar to those seen in pure epithelial counterparts, suggesting somatic derivation of the germ cell component. These rare tumors portend a poor prognosis and understanding their origin has clinical and therapeutic implications.

Endometrial, Ovarian, and Peritoneal Involvement by Endometrioid Carcinoma, Yolk Sac Tumor, and Endometriosis: Molecular Evidence for a Shared Precursor

Recent studies have provided molecular confirmation that a subset of yolk sac tumors is somatically derived. Somatically derived yolk sac tumors are typically diagnosed in older women and are often seen adjacent to epithelial proliferations (such as endometriosis or endometrioid carcinoma) with which they share mutations. Here, we present a case of a postmenopausal woman with a yolk sac tumor and endometriosis in the right ovary, endometriosis with glandular crowding and reactive changes in the left ovary, endometrial endometrioid carcinoma, and yolk sac tumor involving the serosa of the colon. Targeted next-generation sequencing of these five tumor components demonstrated identical mutations in PTEN (p.R130G), PIK3CA (p.G1049S), FGFR2 (p.S252W), and FBXW7 (p.R689Q), suggesting that all components arose from a common precursor. The endometrial endometrioid carcinoma harbored additional exclusive mutations involving PIK3CA (p.H1048R) and CTNNB1 (p.S37F).

Somatic yolk sac differentiation in tumors of the gynecologic tract: A report of two cases and review of the literature

•Somatic yolk sac tumor differentiation associated with malignant neoplasms is uncommon and associated with poor outcome.•In the gynecologic tract, somatic yolk sac differentiation most often arises in postmenopausal patients.•Somatic yolk sac differentiation shares driver mutations with and likely differentiates from the corresponding carcinoma.•This is the first report of somatic yolk sac differentiation in the gynecologic tract from a non-epithelial malignancy.

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.

Yolk sac tumor presenting as a colonic mass in a post-menopausal woman: A case report

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Yolk sac tumors are quite rare in post-menopausal women.

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Yolk sac tumors with endometrial primary origin also may present with abnormal uterine bleeding.

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Patients with unclear abdominal symptoms, mass on imaging, and positive tumor markers raises suspicion of yolk sac tumor.

Uncommon and Difficult High-Grade Endometrial Carcinomas

This article presents features of uncommon high-grade endometrial carcinomas that often pose a significant diagnostic challenge. An update on undifferentiated and dedifferentiated endometrial carcinoma is first provided, followed by discussions on more recently defined entities such as mesonephric-like carcinoma of the endometrium and gastric-type endometrial carcinomas. Finally, endometrial carcinoma with germ cell or trophoblastic-like components is discussed.

Extrauterine Mesonephric-like Neoplasms: Expanding the Morphologic Spectrum

Mesonephric-like adenocarcinomas (MLA) are rare neoplasms arising in the uterine corpus and ovary which have been added to the recent 2020 World Health Organization Classification of Female Genital Tumors. They have similar morphology and immunophenotype and exhibit molecular aberrations similar to cervical mesonephric adenocarcinomas. It is debated as to whether they are of mesonephric or Mullerian origin. We describe the clinical, pathologic, immunohistochemical, and molecular features of 5 cases of extrauterine mesonephric-like proliferations (4 ovary, 1 extraovarian), all with novel and hitherto unreported features. These include an origin of MLA in extraovarian endometriosis, an association of ovarian MLA with high-grade serous carcinoma, mixed germ cell tumor and mature teratoma, and a borderline ovarian endometrioid tumor exhibiting mesonephric differentiation. Four of the cases exhibited a KRAS variant and 3 also a PIK3CA variant. In reporting these cases, we expand on the published tumor types associated with MLA and report for the first time a borderline tumor exhibiting mesonephric differentiation. We show the value of molecular testing in helping to confirm a mesonephric-like lesion and in determining the relationship between the different neoplastic components. We provide further evidence for a Mullerian origin, rather than a true mesonephric origin, in some of these cases. We also speculate that in the 2 cases associated with germ cell neoplasms, the MLA arose out of the germ cell tumor.

Molecular characterization of uterine and ovarian tumors with mixed epithelial and germ cell features confirms frequent somatic derivation

Ovarian germ cell tumors, including yolk sac tumors, are most commonly diagnosed in children and young women. Most so-called yolk sac tumors reported in women >35 years old have been associated with an epithelial proliferation (endometriosis or carcinoma). Here, we describe eight cases clinically diagnosed as uterine or ovarian germ cell tumors in women >35 years old. In addition to routine morphologic examination and immunohistochemical evaluation, we present data from targeted next-generation sequencing (NGS) and isochromosome (12p) fluorescence in situ hybridization (FISH). We identified two groups of tumors with mixed germ cell and epithelial features: (1) tumors with background endometriosis and endometrioid carcinoma-like mutations (PTEN, PIK3CA, FGFR2, and CTNNB1), and (2) high-grade morphology, presumptive presence of isochromosome (12p) by FISH, and TP53 or PIK3CA mutations. These findings support the notion that the "germ cell tumor" component of these tumors is often somatically derived. Two tumors in our cohort were from premenopausal women; one showed no detectable mutations by NGS (suggestive of germ cell derivation), whereas the other showed PIK3CA, PTEN, and CTNNB1 mutations (suggestive of somatic derivation). Accurate classification of these tumors is likely important for selection of appropriate chemotherapy.

Malignant tumours of the uterus and ovaries with Mullerian and germ cell or trophoblastic components have a somatic origin and are characterised by genomic instability. Histopathology 2020;77:788-797. [PMID: 32558949 DOI: 10.1111/his.14188]

AIMS

Tumours of the female genital tract with a combination of malignant Mullerian and germ cell or trophoblastic tumour (MMGC/T) components are usually diagnosed in postmenopausal women, and pursue an aggressive clinical course characterised by poor response to therapy and early relapses. These clinical features suggest that MMGC/T are somatic in origin, but objective molecular data to support this interpretation are lacking. This study evaluates the molecular features of nine MMGC/T, including seven tumours containing yolk sac tumour (YST), one tumour containing choriocarcinoma and one tumour containing epithelioid trophoblastic tumour. The objectives were to: (i) investigate whether MMGC/T show a distinct genetic profile and (ii) explore the relationship between the different histological components.

METHODS AND RESULTS

Next-generation sequencing of paired samples demonstrated that the mutational profile of the Mullerian and non-Mullerian components of the tumour were almost identical in all cases. Moreover, the driver mutations identified were those expected in the specific subtype of Mullerian component present in each case. In contrast, variants expected in postpubertal germ cell tumours and gestational trophoblastic tumours were not identified, and FISH for i(12p) was negative in all cases tested. In this study, mismatch repair-proficient MMGC/T (eight of nine) were characterised by a complex copy-number variant profile, including numerous focal, regional, arm-level and chromosome-level events.

CONCLUSIONS

Comparison of paired samples supports that the YST and trophoblastic tumour components of MMGC/T have a somatic origin and often show numerous copy-number variants, suggestive of underlying genomic instability.

A Comprehensive Review of Biomarker Use in the Gynecologic Tract Including Differential Diagnoses and Diagnostic Pitfalls

Morphologic (ie, hematoxylin and eosin) evaluation of the Mullerian tract remains the gold standard for diagnostic evaluation; nevertheless, ancillary/biomarker studies are increasingly utilized in daily practice to assist in the subclassification of gynecologic lesions and tumors. The most frequently utilized "biomarker" technique is immunohistochemistry; however, in situ hybridization (chromogenic and fluorescence), chromosomal evaluation, and molecular analysis can also be utilized to aid in diagnosis. This review focuses on the use of immunohistochemistry in the Mullerian tract, and discusses common antibody panels, sensitivity and specificity of specific antibodies, and points out potential diagnostic pitfalls when using such antibodies.

Ovarian yolk sac tumor in postmenopausal females: A case series and a literature review

RATIONALE

Ovarian yolk sac tumors (YSTs) are the second most common histologic type of ovarian germ cell tumors. Most patients are adolescent and young women, while cases in postmenopausal women were rarely reported. Due to its rarity, we know little about the treatment and prognosis of postmenopausal patients with ovarian YSTs. We reported 3 cases of mixed ovarian YST in postmenopausal females reviewed the related current English literature.

PATIENT CONCERNS

The ages of the three patients were 61, 58 and 77 respectively. The three patients came to the hospital because of the abdominal discomfort or tenderness, and the third patient also has vaginal bleeding.

DIAGNOSES

Imaging examination revealed pelvic mass with cystic and solid components. The elevated serum AFP level and pathologcial examination confirmed mixed ovarian YST.

INTERVENTIONS

All patients received surgery and chemotherapy. Two patients received PEB (cisplatin, etoposide, and bleomycin) chemotherapy initially and one patient received TC (paclitaxel carboplatin) chemotherapy.

OUTCOMES

One patient relapsed 8 months after diagnosis and underwent re-cytoreductive surgery. The three patients all survived at last follow-up.

LESSONS

The diagnosis of postmenopausal ovarian YST is relatively difficult and it can coexist with other germ cell or epithelial tumors. Postmenopausal ovarian YSTs are aggressive, and may have a worse prognosis compared with those in young patients. More aggressive treatment is needed. When YST mixed with epithelial cancer components, adjuvant chemotherapy regimen should include platinum-based chemotherapy aiming at both epithelial ovarian cancer and germ cell tumors.

Yolk Sac Tumor in Extragonadal Pelvic Sites: Still a Diagnostic Challenge

We present the clinicopathologic features of 15 cases of extragonadal yolk sac tumor (EGYST) detected in female patients and reviewed at our institution from 1988 to 2016. We recorded: patient age, clinical presentation, tumor location, FIGO stage (where applicable), histologic patterns including presence/absence of Schiller-Duval bodies, other germ cell or somatic components, immunoperoxidase results, treatment, and outcome. Patients' ages ranged from 17 to 87 (median, 62) years and presentation included: abnormal uterine bleeding, 12; hematuria, 1; labial mass, 1; abdominal pain, 1. Primary sites were as follows: uterus (11), vagina (1), vulva (1), bladder (1), and peritoneum (1). Seven patients presented at FIGO stage III or IV. The following histologic patterns were observed: microcystic/reticular (7), glandular (8), solid (8), papillary (5), and hepatoid (1). An admixture of histologic patterns was present in 10 cases. Schiller-Duval bodies were seen in only 3 (23%) cases. Eight cases (46%), all uterine primaries, had associated somatic components, and 2 (15%) had a second germ cell component. In 13/14 (93%) cases, the yolk sac tumor component was either missed or misclassified as adenocarcinoma. Immunoperoxidase studies facilitated the diagnosis in all cases as follows: SALL4, 12/12; CDX2, 10/12; α fetoprotein, 7/14; glypican-3, 9/10; cytokeratin 20, 5/9 (rare cells); cytokeratin 7, 3/12 (nondiffuse); PAX8, 2/9 (variable expression). All patients received chemotherapy and all except 1 underwent surgical resection. Follow-up from 5 to 86 months was available for 13 patients: 5 died of disease, 6 are alive with disease, and 2 have no evidence of disease. EGYST arising in the female pelvis of peri/postmenopausal patients may be associated with a somatic component and represent either somatically derived YST or YST differentiation within a somatic carcinoma. EGYST in younger patients is likely a true germ cell neoplasm, and may respond to germ cell appropriate chemotherapy. The benefit of germ cell appropriate chemotherapy in somatically derived EGYST is less clear. Awareness that the presence of glandular or microcystic patterns may lead to under-recognition or misdiagnosis of EGYST in combination with immunomarkers for germ cell and yolk sac differentiation will facilitate the diagnosis.

High-level expression of divergent endodermal lineage markers in gonadal and extra-gonadal yolk sac tumors

Yolk sac tumors occur at both gonadal and extra-gonadal sites. A recent case of ovarian endometrioid-pattern yolk sac tumor with strong diffuse expression of TTF-1 illustrated the potential for misdiagnosis due to divergent expression of endodermal lineage markers. The aim of this study was to investigate the expression of four divergent endodermal lineage markers, TTF-1, CDX2, Hep Par 1, and Napsin A, in gonadal and extra-gonadal yolk sac tumors of differing age, sex, and location (excluding foci of overt hepatoid differentiation). We identified 26 cases (5 ovarian, 15 testicular, and 6 extra-gonadal) containing yolk sac tumor as identified by typical histology and confirmed by positive immunohistochemical staining for alpha-fetoprotein and glypican-3. Mixed or ambiguous foci were confirmed by immunohistochemistry (SALL4 positive and Oct-4 negative). The relative proportion of three histologic patterns: reticular/cystic, solid/myxoid, and glandular was estimated. Percent positivity for the four divergent endodermal lineage markers was compared within yolk sac tumor areas according to site, age group, and histologic pattern. High-level (>25%) staining for one or more divergent endodermal lineage markers was seen in eleven cases: Hep Par 1 in seven cases, all post-pubertal, TTF-1 in four cases, two ovarian and two extra-gonadal, and CDX2 in three cases, with no age or site predilection. No case highly expressed all three divergent endodermal lineage markers, but four co-expressed high levels of two markers: two ovarian yolk sac tumors with TTF-1 and Hep Par 1, one testicular yolk sac tumor with CDX2 and Hep Par 1, and one extra-gonadal yolk sac tumors with TTF-1 and CDX2. While no absolute correlation of high-level divergent endodermal lineage marker expression with histologic subtype was observed, TTF-1 and CDX2 expression was predominantly seen in reticular/cystic and glandular areas while Hep Par 1 was most frequent in myxoid/solid and glandular areas.

Ovarian Yolk Sac Tumor With High-Grade Serous Carcinoma in a 62-Year-Old Woman

Ovarian yolk sac tumors are germ cell tumors that usually present in children and young women. Rarely, these tumors can arise in older women, usually in conjunction with surface epithelial tumors, suggesting divergent differentiation from the latter. The combination of mixed ovarian yolk sac tumor and high-grade serous carcinoma is rare, with only one case documented in the literature. We present a case of mixed ovarian yolk sac tumor and high-grade serous carcinoma in a postmenopausal woman, including a brief discussion of the immunohistochemical findings and differential diagnosis. Despite the rarity of mixed ovarian yolk sac tumor and surface epithelial tumors, it is important to recognize the biphasic nature of the tumor, which should prompt a thorough immunohistochemical evaluation. The therapeutic and prognostic implications of proper diagnosis cannot be overemphasized.

Post-menopausal presentation of yolk sac germ cell tumour

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Yolk sac germ cell tumours are rare in post-menopausal patients.

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Most involve mixed yolk sac tumours

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Consider diagnosis in patients with a pelvic–abdominal mass and raised AFP