Variable MLH1 promoter methylation patterns in endometrial carcinomas of endometrioid subtype lacking DNA mismatch repair

A lack of DNA mismatch repair (MMR) is observed in approximately 20% of sporadic endometrial tumors, but few of these tumors have mutations in MSH2 or MLH1, the two major MMR genes. Promoter methylation is an important means of silencing transcription, and methylation of the MLH1 promoter has been reported as an important cause of MLH1 inactivation in endometrial cancers. Studies have shown that specific CpG sites within the MLH1 gene promoter are critical for gene expression, but other studies have shown that methylation of both more proximal and more distal sequences are important for MLH1 gene regulation. Here, we used a microsatellite instability assay and MLH1 immunohistochemistry to identify a subset of endometrial carcinomas of the endometrioid subtype lacking MMR. Sequencing of bisulphite-treated DNA from these tumors determined the methylation status of 42 CpG sites across the MLH1 promoter (spanning -204 to -702 bp upstream of the transcriptional start). Unlike the 4 normal endometrial samples that were unmethylated, 17 of 21 MMR-deficient samples showed complete or near-complete methylation and the remaining 4 MMR-deficient samples had a considerable degree of methylation (approximately 50% or greater). Five tumors demonstrated isolated unmethylated CpG sites, despite methylation throughout the rest of the promoter. This underscores the importance of examining the methylation status of at least several CpG sites within the promoter as methylation is not always consistent across DNA. Overall, our findings support the model that density of methylation of CpG sites across the MLH1 promoter is important in determining gene expression.

Invasive squamous cell carcinoma of the vagina during pregnancy

BACKGROUND

Squamous cell carcinoma of the vagina in pregnancy is rare.

CASE

A 28-year-old primigravida with antepartum bleeding at 20 weeks' gestation was diagnosed with squamous cell carcinoma after biopsy of a vaginal mass. The histology revealed an invasive grade 3 squamous cell carcinoma of large-cell, nonkeratinizing type. The patient declined pregnancy termination and immediate radiation treatment. She continued to have episodes of vaginal bleeding and was admitted at 30 weeks' gestation. A decision was made in consultation with the neonatal unit to deliver her at 32 weeks' gestation. After corticosteroid treatment, she was delivered by cesarean delivery. Positive pelvic lymph nodes were noted at surgery. Postoperatively, she received external beam radiation and brachytherapy and concurrent cisplatin chemotherapy. She is disease free 3 years from her original diagnosis.

CONCLUSION

This case emphasizes the importance of a thorough pelvic examination to assess the vaginal walls and cervix at the first prenatal visit and with any antepartum bleeding episode.

Hyperplacentosis: a novel cause of hyperthyroidism

Human chorionic gonadotropin (hCG), which is capable of thyrotropic activity, is believed responsible for the hyperthyroidism of gestational trophoblastic disease and hyperemesis gravidarum. Hyperplacentosis is a condition of heightened trophoblastic activity characterized by increased placental weight and circulating hCG levels higher than those associated with normal pregnancy. We report the first case of hyperthyroidism associated with hyperplacentosis. Correction of the hyperthyroidism occurred after hysterotomy and correlated with declining hCG levels. Hyperplacentosis should be included among the causes of hCG-mediated hyperthyroidism.

Fetus-in-fetu presenting as cystic meconium peritonitis: diagnosis, pathology, and surgical management

Fetus-in-fetu (FIF), a rare congenital anomaly, is a fetus incorporating the well-differentiated tissue of its twin. The authors describe a newborn who presented with massive abdominal distension and severe respiratory distress. Abdominal x-rays showed multiple calcifications. The diagnosis of meconium pseudocyst was made. At emergency laparotomy an irregular fetiform mass was found in the retroperitoneum lying within a fluid-filled amniotic sac. It contained a vertebral column, 10 limblike structures, and cranial and caudal ends, supporting the diagnosis of fetus-in-fetu. This case highlights several important points. FIF often is overlooked in the differential diagnosis of a newborn abdominal mass and, as in this case, may be confused with meconuim pseudocyst. FIF should be differentiated from a teratoma because of the latter's malignant potential. Because this diagnosis is not made until pathological analysis, all parts of the mass should be removed to prevent malignant recurrence.

Effect of passaging on Mer phenotype of human fetal cell cultures

With increasing passage in culture, the human fibroblast cell strain GM11 lost the Mer+ phenotype (the ability to support the growth of adenovirus 5 damaged prior to infection by MNNG). All of 46 embryonic strains prepared either from various organs of 20 fetuses from 6-7 to 13-14 weeks of gestational age or from two hydatidiform moles showed normal repair of MNNG-treated virus. We conclude that human fetal strains are not usually deficient in such repair, and that the behavior of GM11 is atypical.

Serotypes of Ureaplasma urealyticum in spontaneous abortion

Ureaplasma urealyticum was isolated from the tissues of 63 of 264 (24%) spontaneous abortions obtained by unaided vaginal delivery or by suction/sharp curettage and from 22 of 259 (8%) therapeutic abortions obtained by suction curettage. The isolates were serotyped by a modified indirect colony epifluorescence test. No differences in the incidence of specificities in the test and control groups were apparent, although statistical analysis of the data remains to be performed. Nor, based upon preliminary observation of the data, were there general differences in the serovars of these isolates and those obtained from either nongonococcal urethritis or asymptomatic controls.

Salpingitis isthmica nodosa in female infertility and ectopic tubal pregnancy

Salpingitis isthmica nodosa has been studied in relation to female infertility and tubal ectopic pregnancy. The incidence of this lesion in a control Caucasian population was 0.6%, as compared with incidences of 2.86% in an ectopic group and 50% in a small infertility group undergoing tuboplasty. It is suggested that salpingitis isthmica nodosa should be considered as an etiologic factor in these reproductive disorders. Chronic tubal spasm is suggested as the underlying process.