Primary Endometrial Yolk Sac Tumor With Endodermal-Intestinal Differentiation Masquerading as Metastatic Colorectal Adenocarcinoma

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.

Cracking the case: The diagnosis and treatment of a complex high-grade endometrial carcinoma with hepatoid, endometrioid, serous features and somatically derived yolk sac tumor component in a 50 year old female

•Alpha-fetoprotein secreting tumors in gynecologic cancers have a broad differential.•Surgical pathology may provide a more comprehensive picture of tumor heterogeneity than initial biopsy.•Yolk Sac Tumor components intermixed with carcinoma points towards a somatic derivative rather than a collision tumor.•Alpha-fetoprotein can be trended over time to gauge response to treatment of cancers that produce the protein.

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.

Yolk sac tumor of the uterus in a 2-year-old girl: A case report and literature review

BACKGROUND

Extragonadal yolk sac tumors (YSTs) occurring in the uterus are extremely rare. To report a uterine YST case in a prepubertal girl and review literature on uterine YST to outline clinical management in diagnosis and treatment.

CASE

We present a case of a 2-year-old girl who presented with vaginal bleeding and a pelvic mass. The diagnosis of YST was confirmed via biopsy. After four cycles of neoadjuvant chemotherapy combined with cisplatin, etoposide, and bleomycin (PEB), vaginoscopic examination and laparoscopy revealed a uterine YST without metastasis. The patient was treated with laparoscopic hysterectomy and two cycles of PEB postoperatively. During the 18 months of follow-up, the patient remained disease-free.

SUMMARY AND CONCLUSION

Primary uterine YST is extremely rare and no treatment guidelines have been established to date. Surgery combined with PEB chemotherapy is considered effective for uterine YST.

Yolk Sac Tumor in a Recurrence of Colonic Adenocarcinoma With Shared Mutations in APC and TP53 Genes: A Case Report

Only four cases of colorectal adenocarcinoma with a yolk sac tumor (YST) component have been reported in the English literature. No genetic investigation has been performed in these cases. We report a case of colorectal adenocarcinoma in which the recurrent tumor had a YST component. A 49-year-old woman presented with a pelvic tumor three years after endoscopic mucosal resection of sigmoid colon adenocarcinoma. The pelvic tumor consisted of an undifferentiated carcinoma component and a YST component. The serum alpha-fetoprotein level was elevated to 42 ng/mL. Treatment as conventional colorectal carcinoma produced some anticancer effects, but the patient died 14 months after the recurrence and 49 months after the EMR. With the help of the next-generation sequencing results of the recurrent tumor, APC c.835 - 8A > G and TP53 c.524G > A (p.R175H) mutations were identified by direct sequencing in both the primary and the recurrent tumors, confirming the relationship between the two metachronous tumors.

α-Fetoprotein-Producing Endometrial Carcinoma Is Associated With Fetal Gut-Like and/or Hepatoid Morphology, Lymphovascular Infiltration, TP53 Abnormalities, and Poor Prognosis: Five Cases and Literature Review

The clinicopathological, immunohistochemical, and molecular characteristics of α-fetoprotein (AFP)-producing endometrial carcinoma (AFP+ EC) are poorly understood. From 284 cases of endometrial carcinoma in our pathology archive, we identified five cases (1.8%) of AFP+ EC with fetal gut–like (4/5) and/or hepatoid (2/5) morphology. All cases exhibited lymphovascular infiltration. In addition, 24 cases of endometrial carcinoma with elevated serum AFP levels were retrieved from the literature. The patient age ranged from 44 to 86 years (median: 63). Of 26 cases whose FIGO (International Federation of Gynecology and Obstetrics) stage and follow-up information was available (mean follow-up 24 months), 15 were stage I or II and 11 were stage III or IV. Even in stage I or II disease, death or relapse occurred in more than half of the patients (8/15). Detailed analysis of our five cases revealed that, on immunohistochemistry, AFP+ EC was positive for SALL4 (4/5), AFP (3/5), and HNF1β (4/5) in >50% of neoplastic cells and negative for estrogen and progesterone receptors (5/5), PAX8 (4/5), and napsin A (5/5). Four cases exhibited aberrant p53 immunohistochemistry and were confirmed to harbor TP53 mutations by direct sequencing. No mutation was found in POLE, CTNNB1, or KRAS. In conclusion, AFP+ EC merits recognition as a distinct subtype of endometrial carcinoma, which occurs in 1.8% of endometrial carcinoma cases, are associated with TP53 abnormalities, exhibit lymphovascular infiltration, and can show distant metastasis even when treated in early stage.

Preservation of sexual and reproductive function in the treatment of extragonadal yolk sac tumors in the female genital tract

OBJECTIVE

This study aimed to summarize the clinical features, treatment modalities, therapeutic effects, menstruation and fertility outcomes, and prognosis of extragonadal yolk sac tumors (YSTs) of the female genital tract.

METHODS

We reviewed 32 cases of extragonadal YSTs in the genital tract treated between 1983 and 2021. The medical records, including clinical characteristics, histopathology, treatments, chemo-reduced adverse events, and outcomes on long-term follow-up, were collected.

RESULTS

Among the 32 cases, 30 were vaginal YSTs and two were uterine YSTs (endometrial and cervical). Thirty patients (30/32, 93.8%) were <4 years. Abnormal vaginal bleeding (n = 31) and elevated serum alpha-fetoprotein level (n = 32) were the most common presentations. Vaginohysteroscopy and/or pediatric rhinoscopy were used for diagnosis in 17 pediatric patients and evaluation of chemotherapeutic efficacy in 21 pediatric patients. All the patients received combination chemotherapy. Bleomycin/etoposide/cisplatin (BEP) was chosen with prior consideration in 28 cases; 21 patients were treated with BEP alone. Yellow or grayish-yellow tissue with irregular shape was found in 66.7% of the cases during repeat examinations. Five patients underwent surgeries during repeat examinations and follow-ups, and no evidence of malignancy was noted in them. Thirty-one patients achieved complete remission. During a median follow-up of 63 months (2.4-240.3 months), two patients experienced recurrence, three died, and 29 remained disease-free. One patient recovered menstruation and five had undergone menarche.

CONCLUSION

BEP chemotherapy can serve as a preferred treatment modality for vaginal and uterine YSTs. Vaginohysteroscopy and pediatric rhinoscopy can be used for diagnosis and evaluation of chemotherapeutic efficacy in pediatric patients. YSTs possibly appear as yellow or grayish-yellow after chemotherapy.

Use of targeted therapy and immunotherapy for the treatment of yolk sac tumors in extragonadal pelvic sites: two case reports

We present the clinicopathologic features and treatments of two cases of extragonadal yolk sac tumor (EGYST) detected in young females, including one in the myometrium admitted in 2013 and another in the serosal layer of the anterior wall of uterus admitted in 2019. The following details were recorded: patient age, clinical presentation, tumor location, International Federation of Gynecology and Obstetrics (FIGO) stage (where applicable), histologic patterns including Schiller-Duval (SD) bodies, other germ cell or somatic components, immunoperoxidase results, treatment, and outcome. The patients were aged 18 and 32 years old, both displayed the clinical manifestation of pain in the lower abdomen, tumor sizes were 10 and 8 cm, respectively, and alpha-fetoprotein (AFP) was significantly increased (1,210-20,251.0 ng/mL). Both participants underwent surgery and typical SD bodies were observed in postoperative pathology. Immunohistochemistry (IHC) results indicated that they were AFP positive (+) and Sal-like protein 4 (SALL4) (+). Both patients received multi-line chemotherapy after surgery, and participant 2 received targeted therapy and immunotherapy. At 36 months after surgery, one patient died, and the other was still receiving treatment. The benefit of germ cell appropriate chemotherapy in somatically derived EGYST has not been fully elucidated. Our report first showed that it is possible to reduce the recurrence rate and improve the prognosis of patients with EGYST by adding targeted therapy and immunotherapy (bevacizumab + tislelizumab) to traditional chemotherapy regimens.

Pure primary yolk sac tumor of the endometrium tends to occur at a younger age: A case report and literature analysis

We present a case of primary yolk sac tumor of the endometrium. This rare tumor occurred in a 43-year-old woman with a pure primary yolk sac tumor. The tumor resembled yolk sac tumor morphology of the ovary. Tumor cells expressed SALL4, AFP, GPC-3, and AE1/AE3 and were focal positive for PAX8. EMA, ER, and PR, among others, were negative. We further analyzed 29 reported cases of this rare tumor in the literature. In total, 17 of 30 patients (57%) had pure endometrial yolk sac tumor, and 13 (43%) had a concomitant somatic neoplasm (endometrial adenocarcinoma was the most common). Although the average age was 52 years (range: 24–87 years), patients with pure yolk sac tumor were younger than those with concomitant somatic tumors, with a mean age of 44.41 years (24–68 years) versus 61.92 years (28–87 years), P = 0.008. Patients with endometrial yolk sac tumor combined with somatic tumor tend to have a slightly higher stage and a poor prognosis.

Case Report: Extragonadal Yolk Sac Tumors Originating From the Endometrium and the Broad Ligament: A Case Series and Literature Review

Yolk sac tumors (YSTs) of the endometrium and the broad ligament are very rare, with only 29 cases and one case of each other reported before in the English literature. Due to lack of standard guidelines, the treatment strategies of these diseases are controversial. Here, we share two cases of YSTs originating from the endometrium and the broad ligament respectively and review related literature. A 35-year-old woman was diagnosed with endometrial YST in our center and underwent surgery followed by chemotherapy with BEP (bleomycin, cisplatin and etoposide) regimen for six courses. After follow-up for 21 months, there is still no evidence of relapse. Another 36-year-old woman was admitted to our department with YST of the broad ligament. She was treated with surgery followed by chemotherapy with BEP regimen and was lost to follow-up after completing therapy. The case of endometrial YST we shared was similar to cases reported before, while the case with YST of the broad ligament we shared was the second case reported worldwide. Both of these two cases were treated with surgery combined with chemotherapy with BEP regimen.

Yolk sac tumor of the endometrium in a post-menopausal woman: Case report and review of the literature

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Seven of eighteen postmenopausal female endometrial YST cases were pure YST.

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IHC supports somatic tumor cell retro-differentiation yielding extra-gonadal YST.

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Studying genetic alterations in endometrial YST may elucidate its histiogenesis.

Endometrial Carcinomas with Intestinal-Type Metaplasia/Differentiation: Does Mismatch Repair System Defects Matter? Case Report and Systematic Review of the Literature

BACKGROUND

Intestinal metaplasia/differentiation in primary endometrial carcinomas is an uncommon phenomenon, with only few cases described.

MATERIAL AND METHODS

We performed a systematic review of endometrial carcinomas with intestinal metaplasia/differentiation interrogating the electronic databases Pubmed, Web of Science, and Scopus, and we reported an additional case arising in a 49-year-old woman.

RESULTS

We identified only eight patients diagnosed with endometrial carcinomas exhibiting intestinal metaplasia/differentiation, and additionally our case. Endometrial carcinomas with intestinal-type features can present in pure or mixed forms in association with usual-type endometrioid carcinomas; in mixed forms, the two neoplastic components may derive from a common neoplastic progenitor, as evidenced by the concomitant loss of MSH2 and MSH6 protein expression in our case. Disease recurrences occur in a significant fraction of the cases, including patients diagnosed in low-stage disease.

CONCLUSIONS

Endometrial carcinomas with intestinal metaplasia/differentiation are rare and they may represent a more aggressive tumor variant, thus requiring a proper treatment despite the low-tumor stage. The ProMise classification should be performed also in these unusual tumors, since they can be associated with mismatch repair system defects.

Yolk sac tumor of endometrium: A case report and literature review

OBJECTIVE

To report a rare case of endometrial yolk sac tumor (YST) and review published cases of YST of the endometrium.

CASE REPORT

A 68-year-old female presented with intermittent vaginal spotting for nine months. An endometrial biopsy showed adenocarcinoma. Complete surgical staging operation was performed and the final pathology revealed stage II endometrial yolk sac tumor. The post-operative α-fetoprotein (AFP) level was 133.4 ng/mL. Post-operative adjuvant chemotherapy with bleomycin, etoposide, and cisplatin (BEP) regimen was prescribed for 6 cycles. AFP levels were normal before the fourth cycle of chemotherapy. She is disease free 6 months after completion of therapy.

CONCLUSION

Primary YSTs arising in the endometrium is an extremely rare disease especially in postmenopausal women. Complete surgical staging operation with adjuvant chemotherapy will lead to good outcome in this disease.

Endometrial tumors with yolk sac tumor-like morphologic patterns or immunophenotypes: an expanded appraisal

Uterine yolk sac tumors have gained increased recognition in recent years. The current study is a multi-faceted examination of yolk sac tumor-like phenotypes in endometrial tumors, based on an analysis of 3 groups of uterine tumors: Group 1: 9 endometrial tumors that had been classified as yolk sac tumor, or as having a yolk sac tumor component, were assessed with a 35-marker immunohistochemical panel, with the goal of defining their immunophenotypic spectrum; Group 2, comprised of 70 endometrial carcinomas of various histotypes, were analyzed for their expression of SALL4, Glypican-3, and AFP, to assess the specificity of these markers for yolk sac tumors relative to endometrial carcinomas; Group 3, comprised of 626 archived cases of endometrial carcinoma/carcinosarcoma, reviewed to define the frequency of yolk sac tumor-like morphology therein. Yolk sac tumor areas in the Group 1 cases were consistently immunoreactive for SALL4 and Glypican-3; variably positive for AFP (89%), Villin (89%), PLAP (78%), 34βE12 (67%), CAM 5.2 (62.5%), EMA (56%), CD117 (50%), p16 (50%), CDX2 (44%), p53 (44% aberrant), MOC31 (37.5%), CK7 (33%), GATA3 (33%), CK5 (25%), and PAX8 (11%); and were negative for CD30, Napsin A, OCT4, estrogen, androgen, and progesterone receptors. 29 (41%) of the 70 group-2 cases expressed at least one of the 3 markers, and 96% of the positive cases was a high-grade histotype. Glypican-3, SALL4, and AFP were positive in 30, 20, and 2.8% of group-2 cases respectively; however, co-expression of any 2, or all 3 markers was uncommon (<9 and 1.4% of cases respectively). Potential yolk sac tumor-like morphology was identified in 5 (0.8%) of 626 group-3 cases, and three were ultimately deemed to be true yolk sac tumor phenotypes based on their morphologic and immunophenotypic similarity to the group 1 cases. These findings highlight the broad immunophenotypic spectrum of uterine yolk sac tumors, the potential pitfalls associated with using immunophenotypes alone to define yolk sac tumor differentiation in endometrial carcinoma, and the utility and limitations of morphologic assessment to identify yolk sac tumors at this site.

Primary yolk sac tumor of the endometrium: a case report and review of the literatures

PURPOSE

Yolk sac tumor (YST) is a malignant tumor derived from germ cells and usually occurs in the gonads. Extra-gonadal YST is most commonly seen in the vagina of children, but rarely in the cervix, vulva and endometrium. Primary YST of endometrium was extremely rare, standard treatment was still controversial and no guideline was established so far. The aim of the present study was to provide a comprehensive understanding and systematic thought for the management of primary YST of endometrium.

METHODS

A systematic research of the literature was conducted in Scopus, PubMed database and Cochrane Library, including case reports and case series. We summarized clinical characteristics, treatments and prognosis of all collected cases. We collected data regarding patients, serum AFP level, initial symptoms, surgical information, postoperative chemotherapy and radiotherapy. A new case was also discussed.

RESULTS

We found only 26 cases have been reported previously. We reported a new case of primary endometrial YST in a 27-year-old woman, and in this case, we creatively performed bilaterally ovarian preservation and used DC (docetaxel and carboplatin) regimen of postoperative chemotherapy, we achieved a relatively good prognosis during the follow-up period of 14 months.

CONCLUSION

Primary YST of endometrium, kind of highly malignant germ cell tumors, was extremely rare, of which initial symptom is usually abnormal vaginal bleeding. Standard treatment was still controversial and no guideline was established so far. Surgery combining with postoperative chemotherapy was considered effective for treatment of primary endometrial YST. Decision on whether to preserve ovaries in young patient with early stage needs careful consideration, comprehensive preoperative assessment and full communication. Intraoperative biopsy and strict postoperative follow-up are recommended. However, standard chemotherapy regimen and feasibility of postoperative radiotherapy remains to be discussed.

Clear Cell Carcinoma of the Cervix With Choriocarcinomatous Differentiation: Report of an Extremely Rare Phenomenon Associated With Mismatch Repair Protein Abnormality

The presence of trophoblastic differentiation or nongestational choriocarcinoma in a carcinoma is rare but has been described in various organs, including in the female genital tract. We report a cervical clear cell carcinoma admixed with a component of choriocarcinoma in a 52-year-old woman, only the second report of this combination in the literature. Immunohistochemically, the tumor exhibited isolated loss of staining with the mismatch repair protein MSH6. We review the literature on trophoblastic differentiation in cervical carcinoma.

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.

Intestinal differentiated mucinous adenocarcinoma of the endometrium with sporadic MSI high status: a case report

Background

Intestinal differentiation of primary mucinous adenocarcinoma of the uterine corpus is exceedingly rare in comparison to the approximately 25% rate in endocervical and ovarian mucinous carcinoma. Additionally, little is known about the related genetic and epigenetic alterations, even though large-scale molecular characterisation of the different types of endometrial cancer took place in the TCGA project along the entities defined by the recent WHO classification.

Case presentation

We present a 62-year-old patient harbouring a primary mucinous carcinoma of the uterine corpus with a morphological resemblance to mucinous colorectal adenocarcinoma. The intestinal differentiation was substantiated by CDX2 and CK20 positivity in the absence of PAX8, p16, WT1, p53, ER, PgR, AFP, SALL4 and Glypican3. A high MSI status with MLH1 hypermethylation was revealed by molecular testing.

Conclusion

Intestinal differentiation of mucinous adenocarcinoma of the endometrium is a unique observation. Besides morphology, it obviously can share molecular features of sporadic MSI colorectal cancers. It can be speculated that either CDX2 positive morula formation or intestinal metaplasia of the endometrium as rare conditions might be the origin of carcinogenesis for this type II endometrial cancer. Both conditions were not detectable in this case. Of note, categorising endometrial cancers in genetic subgroups like MSI high cancers alone might lead to the integration of likewise morphologically different tumours like the case presented here with intestinal differentiation. Hence, careful genotype-phenotype correlations are warranted for studies of mucinous adenocarcinoma of the endometrium.

Electronic supplementary material

The online version of this article (doi:10.1186/s13000-017-0629-0) contains supplementary material, which is available to authorized users.

Yolk sac tumours of the female genital tract in older adults derive commonly from somatic epithelial neoplasms: somatically derived yolk sac tumours

AIMS

To report 18 yolk sac tumours (YSTs) of the female genital tract (17 ovary, one uterus) in patients aged 40 years or over, most arising from a somatic epithelial neoplasm.

METHODS AND RESULTS

Six patients had pure YST, two were associated with immature teratoma (one with an endometrioid adenocarcinoma) and in 11 there was an epithelial neoplasm comprising high-grade serous carcinoma (HGSC) (n = 5), clear cell carcinoma (n = 1), borderline clear cell adenofibroma (n = 1), endometrioid adenocarcinoma (n = 2), serous tubal intra-epithelial carcinoma (n = 1) and large-cell neuroendocrine carcinoma (n = 1). In one case of pure YST, there was an ipsilateral endometriotic cyst but no other neoplastic component. In two cases, the YST was a hepatoid variant and in most of the others it exhibited predominantly glandular morphology, closely mimicking an epithelial neoplasm.

CONCLUSIONS

Pathologists should be aware of the association between YST and an epithelial neoplasm, the former probably arising from the latter through a process of neometaplasia/retrodifferentiation. Those rare gynaecological pure glandular YSTs in adults may arise secondary to total overgrowth of an epithelial neoplasm. Pathologists need a high index of suspicion to diagnose the YST component, as the morphology is characteristically of a glandular variant with marked morphological overlap with adenocarcinomas. There is also often significant immunophenotypical overlap with epithelial neoplasms, as the YST component may be positive with epithelial membrane antigen (EMA), BerEP4 and cytokeratin 7 (CK7), as well as YST markers. We propose the term 'somatically derived YSTs' for these neoplasms and suggest unification of the terminology between different sites where such neoplasms occur.