Histologic changes in the adrenal gland reflect fetal distress in hydrops fetalis

Trisomy 13 with unusual histological features typically described in Beckwith-Wiedemann Spectrum

Trisomy 13, known as Patau syndrome, is a common aneuploidy with a well-known clinical phenotype. This case report describes a trisomy 13 patient with unusual autopsy findings, including features resembling the Beckwith-Wiedemann Spectrum. Due to abnormalities of gestational ultrasounds, a prenatal karyotype of amniotic fluid cells was performed, which resulted in 47, XY+13. Autopsy microscopy studies identified leptomeningeal glioneuronal heterotopia, which was not described as belonging to Patau syndrome. Other atypical findings were diffuse hyperplasia of pancreatic islets of Langerhans and adrenals enlargement with marked adrenocortical cytomegaly, characteristically seen in the Beckwith-Wiedemann Spectrum. Molecular genetic tests were not performed for the Beckwith-Wiedemann Spectrum. Still, due to the rarity of both disorders, this report may support the evidence that trisomy 13 can affect tissue organization and lead to unusual histopathologic features resembling classic overgrowth disorders.

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.

Do Increased Intra-alveolar Squamous Cells at Autopsy Correlate With Acute Fetal Asphyxia?

It is a generally held concept that finding increased aspirated amniotic fluid squames at autopsy supports a diagnosis of acute fetal asphyxia, the massive aspiration of squames being an indicator of terminal gasping. To evaluate this concept, we identified autopsies on 15 third-trimester stillborns with clinical acute placental abruption (acute asphyxia); 13 also had thymic petechiae and none had severe acute thymic involution, findings also supporting acute asphyxia. Thirty third-trimester stillborns with findings supporting a subacute or chronic mode of death, including severe thymic involution and absence of thymic petechiae, comprised the comparison group. Intra-alveolar squames were scored as 0, no squames; 1+, scattered squames singly or in small groups; and 2+, squames in many alveoli, at least focally in compacted clusters. In all cases, the squames were patchily distributed, and none received a score of 0. In the abruption group, the intra-alveolar squames were scored as 1+ in 12 (80%) and as 2+ in 3 (20%) cases, while in the comparison group, the squames were scored as 1+ in 20 (67%) and 2+ in 10 (33%) cases (P = NS). There was also no difference in the quantification of intra-alveolar squames in term compared to preterm stillborns. In conclusion, quantification of intra-alveolar squames did not aid in separating an acute mode of death (acute asphyxia) from subacute or chronic modes of death.

Pulmonary Neuroendocrine Cell Hyperplasia in Hemoglobin Bart-induced Hydrops Fetalis: A model for Chronic Intrauterine Hypoxia

The pulmonary neuroendocrine system includes pulmonary neuroendocrine cells (PNECs) and neuroepithelial bodies (NEBs) that are distributed throughout respiratory epithelium and regulate lung growth and maturation antenatally. Abnormalities in this system have been linked to many hypoxia-associated pediatric pulmonary disorders. Hemoglobin (Hb) Bart disease is a severe form of α-thalassemia resulting in marked intrauterine hypoxia with hydrops fetalis (HF) and usually death in utero. Affected fetuses can serve as a naturally occurring human model for the effects of intrauterine hypoxia, and we postulated that these effects should include changes in the pulmonary neuroendocrine system. Bombesin immunostaining was used to assess PNECs and NEBs in stillborn fetuses with Hb Bart HF ( n = 16) and with HF from other causes ( n = 14) in comparison to non-HF controls. Hb Bart HF showed a significant increase in the proportion of PNECs in respiratory epithelium ( P = .002), mean number of NEB nuclei ( P = .03), and mean size of NEBs ( P = .002), compared to normal non-HF controls. Significant differences were not observed between HF due to other causes and non-HF controls with normal lungs. Non-HF controls with pulmonary hypoplasia showed significant increases in PNECs compared to HF cases not due to Hb Bart HF, implying HF alone does not cause such increases. In contrast, no significant differences were noted between non-HF controls with pulmonary hypoplasia and Hb Bart cases. Hb Bart HF may provide a useful model for studying the pulmonary neuroendocrine system under chronic intrauterine hypoxia.

Adrenal Histologic Stress-related Changes in Third Trimester Stillbirth

Adrenal histologic changes, including compact cell change (CCC), cystic change (CYC), and adrenal hemorrhage (AH), and their clinical correlations have only infrequently been investigated in stillbirth. We evaluated 75 third trimester singleton stillborns with complete autopsies (30 term and 45 preterm). A total of 58 had unexplained stillbirth and 17 had clinical placental abruption. The mothers were predominantly African-American (89%). CCC and CYC were diagnosed as cytoplasmic eosinophilia and cystic cavities in the definitive cortex, respectively. Adrenal changes were correlated with acute thymic involution (ATI), thymic petechiae, and clinical features, including abruption. CCC, CYC, and AH were present in 58 (77%), 51 (68%), and 15 (20%) of the 75 stillborns, respectively. CCC and CYC were frequently seen together ( P < .001). CCC and CYC were associated with higher ATI grade ( P < .001 and P = .010, respectively). The presence of CCC, but not CYC, was associated with absence of thymic petechiae ( P = .013) and was more frequent with unexplained stillbirth compared to abruption ( P = .017). AH was associated with lower ATI grade ( P = .002), with thymic petechiae ( P < .001), and with abruption ( P = .004). CYC was associated with diabetes ( P = .015). Overall, CCC and CYC were frequent findings and correlated with higher ATI grade, suggesting similar causes and time frames. CCC, but not CYC, correlated with unexplained stillbirth compared to abruption, but its high frequency in both groups limits its usefulness in their separation. AH was more frequent in the abruption group and correlated with lower ATI grade and thymic petechiae, supporting an association with sudden asphyxial death.

Fatty infiltration of the thymus in response to illness in the pediatric population

Under physiologic stress, glucocorticoids contribute to thymic involution. While steroids enhance fatty infiltration, this change has not been well studied in the pediatric thymus during illness. Evaluation of 130 thymuses from fetuses, infants and children determined the frequency of thymic fatty infiltration to be low (25%), particularly in fetal thymus (4%). In most cases, fatty infiltration was focal. There was a significant correlation with duration of illness, but not with patient age, gestational age, or underlying disease. There was significantly less fatty infiltration in fetal thymus compared to post-natal thymus, for the same degree of thymic involution. Only seven cases showed diffuse thymic fatty infiltration; all were post-natal associated with an infectious etiology. In contrast, fetal cases of chorioamnionitis seldom showed fatty infiltration and only focally, implying the stress response of fetal thymus differs post-natal, possibly related to the timing of adipose tissue development and fetal glucocorticoid response to stress.