Adrenal tissue in the placenta: a heterotopia caused by migration and embolism?

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.

Heterotopic Adipose Tissue in the Placental Parenchyma: Case Report

Objective: Reports of heterotopic tissue in the placenta are few and mainly include liver and adrenal cells. We report on adipose tissue found in the placenta. Case report: We present the case of a microscopic finding in a 25-year-old's placenta who suffered from hypertensive disorder in pregnancy. During routine microscopic study, we observed a heterotopic, benign, circumscribed and intervillous nodule of adipose tissue. Conclusion: To our knowledge, there is no other reported case of adipocytes among chorionic villi. Why foreign tissues show up in the placenta remains unknown; however, several new theories offer explanations.

Fetal Origin of Placental Hepatic Nodule

Intraplacental hepatic nodules are extremely rare and range from incidentally identified microscopic nodules to large mass-forming lesions. We describe the case of an incidentally identified intraparenchymal hepatic nodule in the placenta from a near-term delivery of a male infant at 36 weeks gestation. Lesional cells were positive for HepPar1, focally positive for glypican3, and negative for calretinin and alpha-fetoprotein, supportive of hepatocellular origin. Fluorescence in-situ hybridization and chromosomal microarray both showed a male sex chromosome complement (XY) within the nodule, confirming the fetal origin of this nodule. We provide the first report of the confirmed fetal origin of these rare lesions, lending support to the hypothesis that placental hepatic nodules may represent an embryonal rest or residua of abnormal cell migration.

Heterotopic Nodules in the Placenta, an Immunohistochemical Re-evaluation of the Diagnosis of Adrenocortical Heterotopia

BACKGROUND

Rare nodules of heterotopic adrenocortical and hepatic tissue are reported in the placenta. A mechanism for adrenocortical tissue in the placenta has been perplexing, while hepatic tissue is generally considered related to yolk sac primordia. The clear cell morphology of these nodules is similar to the adrenal cortex of the adult; however, the fetal adrenal gland does not usually display clear cells.

METHODS

We stained 9 placental nodules, histologically identical to "adrenocortical" heterotopia of the placenta, to determine whether adrenocortical differentiation could be confirmed. These cases include 3 archival cases initially diagnosed as "adrenocortical" heterotopia.

RESULTS

Immunohistochemical staining with steroid factor-1 (SF-1), HepPar-1, and Arginase-1 showed that these nodules of clear cells are actually hepatic (SF-1 negative, HepPar-1, and Arginase-1 positive). PAS staining suggests that glycogen accumulation is responsible for the clear cytoplasm. In contrast, a nodule of adrenocortical heterotopia near the testis and the adrenal gland from a 38-week-old neonatal autopsy case confirm SF-1 reactivity as expected.

CONCLUSION

We propose that adrenocortical heterotopia in the placenta is a misnomer, and that these subchorionic nodules of clear cells demonstrate hepatic differentiation.

Ectopic Fetal Hepatic Tissue in the Placenta

When an unusual intraplacental lesion is identified during pathologic examination, it becomes of substantial import to determine whether it represents a normal structure, metastasis from the mother, or a primary benign tumor, including those secondary to abnormal embryologic development versus a primary malignant placental tumor. In this case report, we identified an incidental nest of intraplacental cells with nondiagnostic morphology and negative initial Glypican-3 stain in a healthy 35-wk gestation. This negative result prompted a broadening of the differential before ultimately determining this lesion was indeed ectopic liver with positive Arginase-1 and HepPar-1 staining. This may represent the mature hepatocyte phenotype within the lesional cells of this near-term birth, a dichotomy not previously discussed in the literature, which focuses on the fetal hepatocyte phenotype, also rarely seen. In this report, we summarize the previous literature regarding intraplacental ectopic liver, and we propose a sensitive approach to suspected ectopic liver of the placenta that may be sufficient to capture both the fetal and mature hepatocyte immunophenotypes. This approach may extend to other related pathologies including assessment of suspected intraumbilical hepatocytes.

Growth patterns of placental and paraovarian adrenocortical heterotopias are different

Two cases of adrenocortical heterotopia are reported. One is in a full-term placenta. The other is adjacent to the ovarian hilum of an adult. Both are incidental findings. Despite sharing similar histological and immunological features, they show different growth patterns. The literature is reviewed and adrenocortical heterotopias of different locations are compared. New hypotheses of its histogenesis are discussed.

Placental findings after laser ablation of communicating vessels in twin-to-twin transfusion syndrome

As laser ablation of placental vascular communications gains acceptance as treatment option for severe twin-to-twin transfusion syndrome (TTTS), pathologists are increasingly confronted with the interpretation of laser-treated placentas. We present our preliminary institutional experience with the gross and microscopic analysis of these specimens. Patients underwent selective ablation for severe TTTS (Quintero stages II to V) between 16 and 25 wk gestation and the placentas were examined between < 24 h and 19 wk postoperatively. The placental vasculature was injected with gelatin-dye mixtures. The type and number of vascular anastomoses were recorded, followed by routine histopathological analysis of the placenta. Foci of laser impact were identified in all placentas examined within 1 month after laser coagulation. Located along the recipient side of the dividing membrane, the laser-treated vessels appeared hemorrhagic and showed a characteristic abrupt interruption of dye filling after vascular injection. In placentas examined more than 1 month after intervention, the most frequent gross finding was the absence or relative paucity of intertwin anastomoses, associated with subchorionic fibrin deposition. Microscopically, laser-treated vessels showed varying degrees of necrosis, associated with focal hemorrhage, avascular villi, and fibrin deposition in the underlying parenchyma. In some cases of intrauterine fetal demise or placental disruption, no definite laser scars were identified. As expected, the number of residual anastomoses (all types) was significantly smaller in laser-treated placentas than in control monochorionic placentas (2.4 +/- 2.2 [ n = 10] vs. 6.2 +/- 3.2 [ n = 70], P < 0.01). Velamentous cord insertion was noted in 50% of cases; markedly uneven placental sharing in 60%. Detailed analysis of laser-treated placentas and clinicopathological correlation may lead to a better understanding of the pathophysiology of TTTS and continued refinement of therapeutic approaches for this often lethal condition.