Thora S. Steffensen

PLACENTAL PATHOLOGY IN TRAP SEQUENCE: CLINICAL AND PATHOGENETIC IMPLICATIONS

Twin reversed arterial perfusion sequence (TRAP) resulting in an acardiac twin is a rare occurrence. Acardia requires the presence of arterial-arterial anastomosis, with retrograde perfusion of poorly oxygenated blood from the normal twin to the acardiac twin, venous-venous anastomosis carrying blood back from the acardiac to the normal twin, and circulatory failure of the acardiac twin. Although vascular anastomoses in cases of TRAP have been well described, there is little published literature on the microscopic changes in the placenta in TRAP sequence. We report a case of monochorionic monozygotic twins with an acardiac twin, large arterial-arterial anastomosis, and direct continuity of the umbilical cord veins. The placenta showed villous immaturity, striking villous calcifications, and extensive fetal thrombotic vasculopathy of the umbilical vein of the donor twin and the chorionic plate vessels. Thrombi in the umbilical vessels of the acardiac twin have been reported, and trombi in donor twin organs have been seen after fetal demise in utero. But to our knowledge there is no previously reported thrombi in the donor twin umbilical vessels or the chorionic plate veins. This may have implications not only as a possible factor in the etiology of TRAP, but also and more important as a possible risk factor for thrombotic events in the donor twin. Further studies with clinico-pathological correlation are needed to explore this issue.

MIDGUT VOLVULUS CAUSING FETAL DEMISE IN UTERO

Intestinal malrotation has an incidence of 1 per 6000 live births. The most serious consequence of malrotation is volvulus. Midgut volvulus is a rare condition in which the small bowel and proximal colon twist around the superior mesenteric artery, leading to a high-grade proximal bowel obstruction and vascular compromise of the intestine, thereby leading to infarction of the involved intestine. Midgut volvulus rarely occcurs antenatally and is usually not lethal in utero. There are only 7 cases of intrauterine fetal demise caused by midgut volvulus reported in the literature. We report a case of intrauterine fetal demise at 38 weeks of gestation, due to cardiovascular failure and shock from midgut volvulus. Non-specific abnormalities, including ascites and dilated bowel, had been seen on the antenatal ultrasound from the 15th week of gestation. In addition to the volvulus, the fetus had intestinal atresia and arthrogryphosis.

Massive pericardial effusion treated with in utero pericardioamniotic shunt in a fetus with intrapericardial teratoma.

Teratoma is the leading neoplasm diagnosed in neonates and infants. Although over 99% of teratomas found in the fetus and newborn are histologically benign, those tumors may cause death if vital structures are involved or if the airway is compromised. We review the literature on antenatal intrapericardial teratomas and report a case of intrapericardial teratoma, with massive pericardial effusion and fetal hydrops, diagnosed on antenatal ultrasound at 21 weeks of gestation. Pericardioamniotic shunt was placed at 22 weeks and 6 days gestational age. In spite of successful drainage of the pericardial effusion, fetal demise was documented 8 days later, likely due to tumor compression of the heart.

The perforated appendiceal carcinoid in children: a surgical dilemma

The decision for aggressive reoperation after discovery of an appendiceal carcinoid is generally based upon criteria such as size, grade, degree of involvement of the mesoappendix or the appendiceal base, lymphovascular invasion, and the presence of goblet cell or adenocarcinoid features. No guidelines currently exist for the management of perforated appendiceal carcinoids. We present a case of perforated appendiceal carcinoid that was subsequently treated with right hemicolectomy, and we review the pertinent literature.

TWIN-TWIN TRANSFUSION SYNDROME IN A DICHORIONIC-MONOZYGOTIC TWIN PREGNANCY: The End of a Paradigm?

The patient was a 30-year-old female, gravida-5, para-4, referred at 25 3/7 weeks’ gestation with the diagnosis of a dichorionic-diamniotic twin gestation with discordant amniotic fluid volumes. The patient had not previously undergone genetic or therapeutic amniocenteses. The pregnancy was conceived spontaneously. Ultrasound examination at our facility confirmed the presence of a twin gestation with an anterior placenta and a “twin-peak” sign (Figure 1). Twin A had grossly normal anatomy and a maximum vertical

ASSESSMENT OF MUSCARINIC AND NICOTINIC ACETYLCHOLINE RECEPTOR EXPRESSION IN PRIMITIVE NEUROECTODERMAL TUMOR/EWING FAMILY OF TUMOR AND DESMOPLASTIC SMALL ROUND CELL TUMOR: AN IMMUNOHISTOCHEMICAL AND WESTERN BLOT STUDY OF TISSUE MICROARRAY AND CELL LINES

The primitive neuroectodermal tumor (PNET)/Ewing family of tumors (EFT) and desmoplastic small round cell tumor (DSRCT) portend a grave prognosis. Ongoing research in similar neurocrest-derived neoplasms has implicated both the muscarinic acetylcholine receptor (mAChR) and nicotinic acetylcholine receptor (nAChR) in the pathogenesis of these neoplasms. Acetylcholine has been reported to impart a modulatory effect on chemotaxis and proliferation, an effect ameliorated by anticholinergic drugs. The aim of our study is to characterize the pattern of expression of mAChR and nAChR in PNET/EFT and DSRCT, in hopes of discovering a potential target for therapeutic improvements. We examined 34 cases of PNET/EFT and 2 DSRCT retrospectively by immunohistochemical studies. We found that AChRs are overexpressed in a significant number of PNET/EFT and DSRCT. The Western blot analysis of 3 human Ewing sarcoma cell lines confirms the presence of AChRs. Future studies are planned to confirm these results as well as to investigate their potential therapeutic implications.

AROMATASE MAY PLAY A CRITICAL ROLE IN THE PATHOGENESIS OF JUVENILE NASOPHARYNGEAL ANGIOFIBROMA

The pathophysiology of juvenile nasopharyngeal angiofibroma (JNA) has yet to be fully elucidated, but the influence of steroid hormones in their growth has been suggested. This neoplasm is known to afflict adolescent males. However, only a minority of the neoplastic cells express androgen receptors. The expression of estrogen receptor beta by the tumor cells recently has been demonstrated. Aromatase (P450) is an enzyme which is responsible for converting androgens to estrogens. However, the rule of aromatase in the pathogenesis of JNA is unknown. In this study we attempt to explain the hormone-induced growth theory by characterizing the aromatase (P450) in JNA. We examined five sinonasal JNA from adolescent males, all of which stained positive for aromatase. We propose that this enzyme is responsible for the local conversion of androgens into estrogens, which subsequently bind to the estrogen receptors leading to the growth of these tumors.

CONGENITAL PERINEAL HERNIA IN A FETUS WITH TRISOMY 18

Perineal hernias are very rare and mostly reported in adults, with only 7 cases reported in children. We report a female fetus, terminated at 18 weeks of gestation due to trisomy 18. In addition to multiple typical findings of trisomy 18, this fetus had perineal hernia with defect of the perineal skin and prolapse of multiple bowel loops. To our knowledge there are no reported cases of perineal hernia presenting antenatally nor are there reported cases of perineal hernia associated with trisomy 18.

Postmortem ultrasonography of the macerated fetus complements autopsy following in utero fetal demise.

Postmortem evaluation following an in utero fetal demise is essential for determining cause of death and counseling regarding future pregnancies. Severe maceration and fetal size along with patient desires may limit the physicians ability to perform a complete autopsy. In the cases presented, we demonstrate the utility of postmortem ultrasonography as an adjunct to traditional autopsy following fetal demise.

Spondyloepiphyseal dysplasia congenita.

We report a case of spondyloepiphyseal dysplasia congenita (SED congenita), diagnosed at autopsy of a term infant. Prenatal ultrasound at 20 weeks of gestation had shown shortening of all the fetal long bones, with bowing of the femora and humeri, clubfeet, and small thoracic cage. We discuss the diagnostic features of SED and the main differential diagnoses.