Placental Yolk Sac Tumor With Divergent Endodermal Differentiation

Heterotopic Hepatic Tissue in the Placenta: A Case Report

Heterotopic hepatic tissue in placenta or umbilical cord is rare. The exact mechanism by which this heterotopia occurs has not been fully understood but is thought to be related to yolk sac primordia. To date, a handful of such cases have been reported. We present a case of heterotopic liver tissue within a chorionic stem villus of a 37 week-growth restricted neonate and describe the tissue morphology and its immunohistochemistry workup.

Hepatic and Adrenocortical Choristomas in the Placenta

Background Hepatic and adrenocortical choristomas are unusual findings in the placenta. This meta-analysis includes our own case report and 23 previously reported cases. We searched for patterns of associated placental, fetal and maternal aberrations in order to determine whether these choristomas are clinically relevant. Case report: In our case, abortion was induced due to fetal central nervous system and renal malformations. In the placenta a hepatic choristoma (<0.1 cm), thrombangiitis obliterans and a single umbilical artery were found. Results: In the literature, the majority of lesions were ≤1.0 cm (n = 21/24, 87.5%) and two hepatic choristomas manifested within chorangiomas. In a subfraction of cases, we found an association with twin/triple pregnancies (n = 6/24, 25%) and heterogeneous non-hepatic/non-adrenal malformations in fetuses (n = 4/24, 17%). Conclusion: Hepatic and adrenocortical choristomas are benign, could be based on focal epigenetic changes and might be related to chorangiomas but are not associated with a particular disease pattern or risk profile.

Ectopic Liver Within the Placental Parenchyma of a Stillborn Fetus

Rarely, liver tissue can be seen in the umbilical cord, where it is thought to result from ectopic localization during embryogenesis. The placental parenchyma is also a rare site for this occurrence. The exact pathophysiology of ectopic liver in the placenta is unknown. It has been considered that aberrant migration or displacement of cells from the developing hepatic buds leads to ectopic liver formation, including groups of liver cells that become entrapped in the foregut as the diaphragm closes. Additional hypotheses put forward have included monodermal teratoma and hepatocellular adenoma. While the lesions may not actually be adenomas, this term has been most utilized in the literature. Hepatocellular adenomas of the placenta are extremely rare; only 9 cases have been reported thus far. We report an additional occurrence of ectopic liver in the placenta, which is the only one reported in a stillborn, and review the literature.

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.

Fetal and placental malignancies: prenatal diagnosis and management

Fetal and placental malignancies are rare complications during pregnancy, but when they occur they may present significant challenges for the perinatology team. Owing to their rarity, there is limited information on many of these entities, with much data derived from individual case reports or small case series. Prenatal diagnosis of these entities is rare and inconsistent, usually in the form of isolated case reports. In the majority of fetal tumors, prenatal features are those of a mass lesion, with or without other non-specific features of fetal compromise such as polyhydramnios, fetal hydrops or intrauterine death, the final diagnosis in most cases being based on postnatal pathological examination.Expectant management is almost always indicated antenatally, with serial ultrasound examinations performed to detect rapid enlargement, metastasis or secondary fetal complications, such as non-immune hydrops, which may require intervention. Delivery should be planned in a specialist center in conjunction with pediatric surgeons and oncologists to allow appropriate neonatal management. Placental malignancy is most commonly in the form of gestatational trophoblastic disease, which requires assessment and management in specialist centers.