Villous Invasion Research Articles

Placenta percreta: placental villous invasion or a form of adhesive disease?

Introduction. According to the International Federation of Gynecology and Obstetrics (FIGO) classification placenta percreta is the most severe form of placenta accreta spectrum (PAS) which is characterized by placental invasion through the entire myometrium and possible involvement of extrauterine tissues. The disease is associated with prior cesarean sections and placenta previa. This paper presents a clinical case of placenta percreta. The diagnosis was made based on ultrasound and MRI and confirmed intraoperatively. Histological examination revealed thinning of the uterine segment, fibrosis of the posterior wall of the bladder, and adhesions between the uterus and the bladder. We aimed to compare clinical, instrumental, and histological data and intraoperative imaging. Materials and methods. Histological study was performed on paraffin sections (H&E and Mallory staining). We studied immunohistochemistry of cytotrophoblasts and syncytiotrophoblasts with antibodies to cytokeratin-8. Results. MRI and ultrasound examination showed placental invasion extending beyond the serous lining of the uterus and involving the posterior wall of the bladder. At 37 weeks, elective cesarean section and surgical excision of the uterine wall with invaded villi were performed. Histological study revealed invasive cytotrophoblasts in the uterine wall and fibrous bladder wall. Involvement of the bladder wall was due to adhesions and the development of fibrosis. Conclusion. Trophoblast and villous invasion did not extend beyond the uterus. Placenta percreta can be supposed to be one of the forms of pelvic adhesive diseases. Keywords: cesarean section, uterine scar, healing of the uterine wall, placenta accreta spectrum, placenta percreta, invasion

Морфофункциональные, молекулярные и иммунологические изменения в плаценте и периферической крови при патологическом прикреплении плаценты

Introduction. Placenta accreta spectrum is an abnormal invasion of villous trophoblast into the myometrium and one of the most severe complications of pregnancy. We aimed to study morphofunctional, molecular, and immunological changes in the placenta and peripheral blood in various types of placenta accreta spectrum.Materials and methods. The study involved 45 pregnant women who underwent ultrasound examination at weeks 35–38. According to the ultrasound data, 15 women had placenta accreta and 15 women developed placenta increta. The comparison group included 15 pregnant women without placenta accreta spectrum with a uterine scar after cesarean section. Histological and immunohistochemical studies were performed on paraffin sections of the placentas. We used mouse antibodies to insulin-like growth factor-binding protein-1, pregnancy-specific β-1 glycoprotein, and human placental lactogen, proteinase 3 and measured them using ELISA. We also studied tumor necrosis factor. Immunophenotyping of peripheral blood lymphocytes was performed using flow cytometry. Results. Рlacenta accreta spectrum is accompanied by increased intensity of IHC staining of placental villi for all the studied markers, in contrast to those in the comparison group. The maximum intensity of insulin-like growth factor-binding protein-1 staining was found in placenta increta. Increased serum concentration of proteinase 3 and placental lactogen (placenta increta) and decreased level of insulin-like growth factor-binding protein-1 were found in placenta accreta spectrum.Conclusion. In placenta accreta spectrum, there is a functional redundancy of placental proteins and an increased pro-inflammatory status. An imbalance between aggressive factors are likely to contribute to pathological villous invasion. Keywords: placenta accreta spectrum, immune status, placental proteins, proteinase 3

The “rail sign”: an ultrasound finding in placenta accreta spectrum indicating deep villous invasion and adverse outcomes

Ultrasound has demonstrated a high accuracy in the prenatal diagnosis of placenta accreta spectrum. However, it is not known whether ultrasound findings can pinpoint the depths of villous invasion, recommend surgical strategies, and predict clinical outcomes. We described an ultrasound descriptor for the placenta accreta spectrum and investigated whether it can predict the severity of villous invasion and clinical outcomes. The patients with placenta accreta spectrum in this retrospective cross-sectional study were diagnosed and managed in our hospital from 2002 to 2017. The placenta, with overlying myometrium and bladder, was mapped with color Doppler sonography while the patient's bladder was full. A "rail sign" was defined as 2 parallel neovascularizations depicted by color Doppler sonography over the uterovesical junction and bladder mucosa, with interconnecting bridging vessels perpendicular to both. The patients received serial ultrasound examinations and surgery at our hospital. An unpaired t test and Pearson chi-square test compared the pathology subtypes, surgical strategies, and clinical outcomes in patients with or without a rail sign. We enrolled 133 consecutive cases of placenta accreta spectrum confirmed either by surgical inspection or pathology examination. Patients with a rail sign had a significantly higher risk of an abnormally invasive placenta (placenta increta or placenta percreta) than those patients without a rail sign (83.3% [60 of 72] vs 27.9% [17 of 61]; odds ratio, 12.94; P<.001). In addition, patients with a rail sign had a higher probability of perioperative approaches, including preoperative vascular control (58.3% [42 of 72] vs 21.3% [13 of 61]; odds ratio, 5.17; P<.001) and uterine artery embolization (34.7% [25 of 72] vs 11.5% [7 of 61]; odds ratio, 4.1; P=.0002]. Furthermore, patients with a rail sign carried a higher risk of adverse clinical outcomes than patients without a rail sign, such as blood transfusion (80.6% [58 of 72] vs 36.1% [22 of 61]; odds ratio, 7.34; P<.001], admission to the intensive care unit (33.3% [24 of 72] vs 16.4% [10 of 61]; odds ratio, 2.55; P=.026), hysterectomy (75% [54 of 72] vs 24.6% [15 of 61]; odds ratio, 9.2; P<.001), and bladder invasion (16.7% [12 of 72] vs 4.9% [3 of 61]; odds ratio, 3.86; P=.033). Notably, the negative predictive value of bladder invasion was 95.1%, indicating a high confidence to reject bladder invasion while the rail sign was negative. When the rail sign was used as a screening test, the positive likelihood ratio of predicting deep villous invasion was 3.64 and correlated with an increased probability of 20% to 25%. Patients with a rail sign also had a greater blood loss (2944±2748 mL vs 1530±1895 mL; P<.001) and a longer hospital stay (11.9±10.9 days vs 8.6±7.1 days; P=.036) than patients without a rail sign. A "rail sign" depicted by color Doppler sonography correlates with deeper villous invasion, additional perioperative approaches, and more adverse outcomes.

Ultrasound-histopathologic features of the utero-placental interface in placenta accreta spectrum

IntroductionThe objective of this study was to evaluate the relationship between utero-placental vascular changes on ultrasound imaging and histopathologic findings according to the grade of villous invasion in placenta accreta spectrum (PAS). MethodsThe ultrasound features of 31 patients with singleton pregnancies diagnosed prenatally with low-lying/placenta previa accreta were compared with histopathology findings following caesarean hysterectomy (n = 25) or partial myometrial resection (n = 6). The number and degree of transformation of arteries within the superficial layer of myometrium were recorded. Cytokeratin 7 (CK7) immunohistochemistry was used to complement H&E analysis. ResultsAll 31 patients presented with loss of clear zone, myometrial thinning and placenta lacunae. Subplacental hypervascularity and lacunae feeder vessels were found in 25 and nine cases, respectively. Large recent intervillous thromboses were found in one case with adherent villi and 12 cases with invasive villi, and showed a significantly different distribution according to lacunae scores. Thick basal plate fibrinoid deposits were found in all the areas of abnormally adherent and invasive villous tissue There was no significant difference in the mean count of partially remodeled vessels or vessels completely lacking remodeling according to the lacunae score and grade of placental invasiveness. EVT cells were arranged in superficial confluent sheets or superficial irregular clusters, or were scattered deep below the basal plate. ConclusionPlacental ultrasound and histopathologic features associated with PAS are more pronounced in invasive cases suggesting that they are secondary to the haemodynamic effects of abnormally deep placentation and transformation of the radial and arcuate arteries.

A new methodologic approach for clinico-pathologic correlations in invasive placenta previa accreta

The development of new management strategies for women presenting with placenta accreta spectrum requires quality epidemiology data, which have so far been limited by the high variability in clinical and histopathologic data confirming the diagnosis at birth. To evaluate the role of a new methodologic approach for the correlation of clinical and pathological data for women with a history of prior cesarean delivery diagnosed prenatally with placenta previa accreta. A modified pathologic technique for gross examination of hysterectomy specimens with placenta in situ consisting of intraoperative examination, immediate postoperative examination, and guided histologic sampling was used prospectively in a cohort of 24 patients with singleton pregnancies complicated by placenta low-lying/placenta previa accreta. Maternal characteristics, detailed ultrasound findings, surgical outcomes, and histopathologic examination were compared with those of a group of 24 patients with similar clinical characteristics and in whom a standard pathologic examination method was used. The median reporting time for obtaining the complete histopathology results including the microscopic examination was significantly shorter (7 versus 15 days; P < .001) and the median number of samples taken for histologic examination significantly lower (4 versus 14 samples; P < .001) in the study group than in the controls. The number of histologic slides showing villous invasion was significantly higher (2 versus 1 slide; P= .002), and the ratio of the number of samples taken to the numbers of slides confirming villous invasion was significantly lower (2 versus 9; P < .001) in the study group than in the controls. In all cases in the study group, intraoperative examination identified a dense tangled bed of vessels or multiple vessels running laterally and cranio-caudally in the uterine serosa above the placental insertion that were no longer visible during immediate gross postoperative examination of the hysterectomy specimens. Immediate postoperative dissection enables the differential diagnosis between focal and large increta areas, and between abnormally adherent placenta and invasive placenta accreta. Valuable clinical information on the serosal vascularity, uterine dehiscence, and extension of the accreta area is added with the description of the macroscopic examination during the surgical procedure and immediate dissection of the specimen. This methodological approach is cost-effective and increases the quality of the histologic sampling. It thus provides more accurate correlations with the clinical data and more accurate epidemiologic data collection. Perinatal pathologists should be part of multidisciplinary teams involved the management placenta accreta spectrum disorders.

A Rare Case of Placental Metastasis in Gastric Cancer

Introduction Gastric Cancer during Pregnancy is a very uncommon event. Of all the cancers to be described during pregnancy, Gastric cancer accounts for 0.1 %. To have metastasis to the placenta, is extremely rare. We describe a case of Gastric cancer diagnosed as a result of complications from pregnancy that had further metastasized to the placenta. Case description A 31 year old lady presented to the hospital for evaluation of low back pain at 33 weeks in pregnancy. She was noted to have HELLP syndrome at that time. Immediate delivery was planned and she underwent a C-section. Post partum course was complicated with post partum hemorrhage requiring intraunterine packing. A placental analysis was subsequently performed which showed presence of tumor cells in between the villi. Adenocarcinoma wa confirmed with a gastric origin based on immunohistochemistry. Upper endoscopy confirmed the presence of the tumor. Further assessment showed distant metastasis. Infant did not show any metastasis on 6 month follow up. Discussion The treatment is complicated and based on the staging of the tumor and gestational age. Diagnosis is often delayed due to First trimester GI symptoms being common. Villous invasion of the tumor is associated with fetal metastasis and can be seen in 20 - 30 % of cases. Previous studies have recommended that a close follow-up of the healthy infant should be performed, including a physical examination, chest X-ray and liver function tests every six-months for the first two years of life. A prior case has suggested termination of the pregnancy if the gestational age is < 22 followed by therapy of the cancer. Conclusion It is extremely rare to have metastatic gastric tumor to be diagnosed during pregnancy. Amongst them, metastasis to placenta is rare. Current treatment is largely anecdotal2670_A Figure 1 No Caption available.2670_B Figure 2 No Caption available.2670_C Figure 3 No Caption available.

A bioinformatics transcriptome meta-analysis highlights the importance of trophoblast differentiation in the pathology of hydatidiform moles

IntroductionHydatidiform mole (HM) is an aberrant human pregnancy with abnormal trophoblastic development, migration/invasion of the extravillous trophoblast in the decidua. These abnormalities are established in a hypoxic environment during the first trimester of gestation. MethodsUsing text mining, we identified 72 unique genes that are linked to HM (HM-linked genes) that we studied by bioinformatic analysis in publicly available transcriptomes of primary chorionic villous cells (cytotrophoblast, syncytiotrophoblast, extravillous trophoblast, and arterial and venous endothelial) isolated from normal placentas or established trophoblastic cell lines cultured under different oxygen concentrations. ResultsWe show that the majority of HM-linked genes (75%) are involved in normal trophoblastic differentiation, arranged in clusters, and some of them are implicated in chorionic villous invasion or regulated by oxygen concentrations. DiscussionOur analysis integrates the various aspects of the pathophysiology of HM and highlights the importance of trophoblastic differentiation in this pathology.

Multidisciplinary treatment of total placenta previa in a blood-refusal parturient for a religious reason.

Women with a history of previous cesarean delivery, presenting with a placenta previa, have become the largest group with the highest risk for placenta previa accreta.The objective of the study was to evaluate the accuracy of ultrasound imaging in the prenatal diagnosis of placenta accreta and the impact of the depth of villous invasion on management in women presenting with placenta previa or low-lying placenta and with 1 or more prior cesarean deliveries.We searched PubMed, Google Scholar, clinicalTrials.gov, and MEDLINE for studies published between 1982 and November 2016.Criteria for the study were cohort studies that provided data on previous mode of delivery, placenta previa, or low-lying placenta on prenatal ultrasound imaging and pregnancy outcome. The initial search identified 171 records, of which 5 retrospective and 9 prospective cohort studies were eligible for inclusion in the quantitative analysis.The studies were scored on methodological quality using the Quality Assessment of Diagnostic Accuracy Studies tool.The 14 cohort studies included 3889 pregnancies presenting with placenta previa or low-lying placenta and 1 or more prior cesarean deliveries screened for placenta accreta. There were 328 cases of placenta previa accreta (8.4%), of which 298 (90.9%) were diagnosed prenatally by ultrasound. The incidence of placenta previa accreta was 4.1% in women with 1 prior cesarean and 13.3% in women with ≥2 previous cesarean deliveries. The pooled performance of ultrasound for the antenatal detection of placenta previa accreta was higher in prospective than retrospective studies, with a diagnostic odds ratios of 228.5 (95% confidence interval, 67.2–776.9) and 80.8 (95% confidence interval, 13.0–501.4), respectively. Only 2 studies provided detailed data on the relationship between the depth of villous invasion and the number of previous cesarean deliveries, independently of the depth of the villous invasion. A cesarean hysterectomy was performed in 208 of 232 cases (89.7%) for which detailed data on management were available. Positive correlations were found in the largest prospective studies between the cumulative rates of the more invasive forms of accreta placentation and the sensitivity and specificity of ultrasound imaging but not with diagnostic odds ratio values. We found no data on the ultrasound screening of placenta accreta at the routine midtrimester ultrasound examination from the nonexpert ultrasound units.Planning individual management for delivery is possible only with accurate evaluation of prenatal risk of accreta placentation in women presenting with a low-lying placenta/previa and a history of prior cesarean delivery. Ultrasound is highly sensitive and specific in the prenatal diagnosis of accreta placentation when performed by skilled operators. Developing a prenatal screening protocol is now essential to further improve the outcome of this increasingly more common major obstetric complication.

Maternal Gastric Adenocarcinoma with Placental Metastases: What is the Fetal Risk?

The incidence of maternal cancer during pregnancy is low, and metastatic disease involving the placenta is rare. We present a case of rapidly progressive and fatal gastric carcinoma presenting during pregnancy, with spread to the maternal blood space within the placenta but no chorionic villous invasion and no evidence of fetal transmission at the time of delivery or on 12-month follow up. To the best of our knowledge, there have been only 5 previous single case reports of gastric carcinoma metastatic to the placenta. This case highlights the need for clinical vigilance against dismissing gastrointestinal symptoms as pregnancy related and for pathologists to carefully examine the placenta in the setting of maternal malignancy. When placental metastases are present but with no villous invasion, the risk of fetal metastasis may be extremely low, even in the setting of aggressive, terminal malignancy in the mother.

Maternal breast carcinoma metastases to the placenta: a case report and literature review

Pregnancy associated with malignancy and placental metastasis is uncommon. Seventy-three cases of placental metastases have been reported in the English literature. The most common pla-cental metastases are from melanoma, followed by haematologi-cal malignancies. We report a case of maternal breast malignancy with placental micrometastasis despite an unremarkable gross placental appearance in a 42-year-old Chinese lady. She was diagnosed with infiltrating ductal carcinoma grade 3 in 2007 and underwent surgery and chemoradiation. She presented recently with an unplanned pregnancy and opted for termination of pregnancy. The placenta was grossly normal. However, microscopy revealed infiltration of chorionic villi by malignant epithelial cells which were immunopositive for ER and PR; negative for b-hCG, S-100protein and HMB-45. The amniotic membranes, umbilical cord and major fetal organs were unremarkable. This case highlights the importance of examination of the placenta in maternal malignancies, as findings have a bearing on management of the patient and newborn (in the case of term pregnancy). Other than microscopy for the presence of malignant cells in the inter-villous space, one needs to scrutinise for malignant villous invasion which is associated with fetal metastasis. This warrants closer and longer follow-up for the infant to detect systemic involvement by malignancy. Pregnancy associated with malignancy and placental metastasis is uncommon. Seventy-three cases of placental metastases have been reported in the English literature. The most common pla-cental metastases are from melanoma, followed by haematologi-cal malignancies. We report a case of maternal breast malignancy with placental micrometastasis despite an unremarkable gross placental appearance in a 42-year-old Chinese lady. She was diagnosed with infiltrating ductal carcinoma grade 3 in 2007 and underwent surgery and chemoradiation. She presented recently with an unplanned pregnancy and opted for termination of pregnancy. The placenta was grossly normal. However, microscopy revealed infiltration of chorionic villi by malignant epithelial cells which were immunopositive for ER and PR; negative for b-hCG, S-100protein and HMB-45. The amniotic membranes, umbilical cord and major fetal organs were unremarkable. This case highlights the importance of examination of the placenta in maternal malignancies, as findings have a bearing on management of the patient and newborn (in the case of term pregnancy). Other than microscopy for the presence of malignant cells in the inter-villous space, one needs to scrutinise for malignant villous invasion which is associated with fetal metastasis. This warrants closer and longer follow-up for the infant to detect systemic involvement by malignancy.

Maternal breast carcinoma metastases to the placenta: a case report and literature review

Pregnancy associated with malignancy and placental metastasis is uncommon. Seventy-three cases of placental metastases have been reported in the English literature. The most common placental metastases are from melanoma, followed by haematological malignancies. We report a case of maternal breast malignancy with placental micrometastasis despite an unremarkable gross placental appearance in a 42-year-old Chinese lady. She was diagnosed with infiltrating ductal carcinoma grade 3 in 2007 and underwent surgery and chemoradiation. She presented recently with an unplanned pregnancy and opted for termination of pregnancy. The placenta was grossly normal. However, microscopy revealed infiltration of chorionic villi by malignant epithelial cells which were immunopositive for ER and PR; negative for b-hCG, S-100 protein and HMB-45. The amniotic membranes, umbilical cord and major fetal organs were unremarkable. This case highlights the importance of examination of the placenta in maternal malignancies, as findings have a bearing on management of the patient and newborn (in the case of term pregnancy). Other than microscopy for the presence of malignant cells in the intervillous space, one needs to scrutinise for malignant villous invasion which is associated with fetal metastasis. This warrants closer and longer follow-up for the infant to detect systemic involvement by malignancy.

Maternal breast carcinoma metastases to the placenta: a case report and literature review

Pregnancy associated with malignancy and placental metastasis is uncommon. Seventy-three cases of placental metastases have been reported in the English literature. The most common placental metastases are from melanoma, followed by haematological malignancies. We report a case of maternal breast malignancy with placental micrometastasis despite an unremarkable gross placental appearance in a 42-year-old Chinese lady. She was diagnosed with infiltrating ductal carcinoma grade 3 in 2007 and underwent surgery and chemoradiation. She presented recently with an unplanned pregnancy and opted for termination of pregnancy. The placenta was grossly normal. However, microscopy revealed infiltration of chorionic villi by malignant epithelial cells which were immunopositive for ER and PR; negative for b-hCG, S-100 protein and HMB-45. The amniotic membranes, umbilical cord and major fetal organs were unremarkable. This case highlights the importance of examination of the placenta in maternal malignancies, as findings have a bearing on management of the patient and newborn (in the case of term pregnancy). Other than microscopy for the presence of malignant cells in the intervillous space, one needs to scrutinise for malignant villous invasion which is associated with fetal metastasis. This warrants closer and longer follow-up for the infant to detect systemic involvement by malignancy. Pregnancy associated with malignancy and placental metastasis is uncommon. Seventy-three cases of placental metastases have been reported in the English literature. The most common placental metastases are from melanoma, followed by haematological malignancies. We report a case of maternal breast malignancy with placental micrometastasis despite an unremarkable gross placental appearance in a 42-year-old Chinese lady. She was diagnosed with infiltrating ductal carcinoma grade 3 in 2007 and underwent surgery and chemoradiation. She presented recently with an unplanned pregnancy and opted for termination of pregnancy. The placenta was grossly normal. However, microscopy revealed infiltration of chorionic villi by malignant epithelial cells which were immunopositive for ER and PR; negative for b-hCG, S-100 protein and HMB-45. The amniotic membranes, umbilical cord and major fetal organs were unremarkable. This case highlights the importance of examination of the placenta in maternal malignancies, as findings have a bearing on management of the patient and newborn (in the case of term pregnancy). Other than microscopy for the presence of malignant cells in the intervillous space, one needs to scrutinise for malignant villous invasion which is associated with fetal metastasis. This warrants closer and longer follow-up for the infant to detect systemic involvement by malignancy.

Gastric carcinoma with metastasis to the placenta and amniotic fluid: case report and review of the literature

Y.R., a 26-year-old Jewish woman gravida-5 para-4, was admitted in week 26 of singleton gestation due to low abdominal and back pain. Two weeks previously she had begun suffering from diffuse abdominal pain. Physical examination revealed a very sick and suffering patient in agony. On examination the uterus was enlarged for 26 weeks’ gestation, with mild abdominal tenderness without peritoneal signs, and an enlarged cervical lymph node. Laboratory test results: hemoglobin 11.2 g%, WBC 7800, platelets 138,000, AST 17 IU/l, ALT 7 IU/l, GGT 24 IU/l, LDH 1089 IU/l, alkaline phosphatase 87 IU/l, albumin 2.1 g% and total protein 4.5 g%. Abdominal ultrasound revealed a 26-week singleton pregnancy appropriate for gestational age. Ovarian vein thrombosis was suspected and she was started on subcutaneous Clexane 60 mg 2/day. Two days later she developed hypovolemic shock due to severe hematemesis. An emergency gastroendoscopy revealed linitis plastica with hypertrophic rugae and ulceration and a gastric biopsy showed a poorly differentiated gastric adenocarcinoma. A CT scan showed metastatic disease, omental thickening, ascites, hepatic metastasis and enlarged mesenteric and a retroperitoneal lymph node. A fine needle aspirate from the cervical lymph node revealed carcinoma. It was decided to treat the patient palliatively. The patient was treated with total parenteral nutrition, morphine and fentanyl. Corticosteroids were given to promote fetal lung maturity. One month after her admission, at 31 weeks, the woman’s condition deteriorated, and an elective Caesarean section under spinal anesthesia was performed. The operation revealed ascites, peritoneal carcinomatosis, liver and diaphragmatic metastasis. A female infant weighing 1384 g, APGAR score 8/9 was delivered, and the placenta and amniotic fluid were sent for pathology. The mother died 57 h after the delivery. The baby was reported doing well at 9 months after delivery, with no evidence of fetal metastases. Macroscopic examination of the placenta showed no gross metastasis. Microscopic analysis revealed malignant cells within the intervillous space without villous invasion, and also in the amniotic fluid. The umbilical cord and membranes appeared normal.

MALIGNANCY METASTATIC TO THE PRODUCTS OF CONCEPTION: A Case Report with Literature Review

Breast cancer is rare in adolescent females. Breast cancer metastatic to the products of conception is equally uncommon. We describe a 15-year-old girl who at 30 weeks of gestation was diagnosed with metastatic adenocarcinoma of probable breast origin. The placenta showed extensive intervillous disease. Metastatic disease within the intervillous space indicates hematogenous dissemination of cancer and a poor prognosis for the mother. The infant is almost always free of maternal disease unless there is villous invasion. Hormonal changes or immunotolerance by the mother may be involved in the pathogenesis. All placentas in which maternal malignancy is known or suspected should be examined grossly and microscopically.

Malignancy Metastatic to the Products of Conception: A Case Report with Literature Review

Breast cancer is rare in adolescent females. Breast cancer metastatic to the products of conception is equally uncommon. We describe a 15-year-old girl who at 30 weeks of gestation was diagnosed with metastatic adenocarcinoma of probable breast origin. The placenta showed extensive intervillous disease. Metastatic disease within the intervillous space indicates hematogenous dissemination of cancer and a poor prognosis for the mother. The infant is almost always free of maternal disease unless there is villous invasion. Hormonal changes or immunotolerance by the mother may be involved in the pathogenesis. All placentas in which maternal malignancy is known or suspected should be examined grossly and microscopically.

Histopathologic findings in ectopic tubal pregnancy.

In 141 consecutive cases of tubal ectopic pregnancy at Hermann Hospital in Houston, Texas, the histologic appearance of 129 surgically removed fallopian tubes containing ectopic pregnancies was reviewed and compared with an age- and race-matched control population. There was a higher incidence of chronic salpingitis (88 versus 2%) and salpingitis isthmica nodosa (SIN) (43 versus 5%). The ectopic pregnancy patients had a higher incidence of pelvic inflammatory disease, gonorrhea, previous abortions, bitubal ligation, intrauterine device use, and previous abdominal surgery. In our population, chronic salpingitis was the most commonly associated finding. The increase in SIN was associated with postinflammatory changes (89%). We also found that ectopic tubal pregnancies may grow either intratubally or extratubally by villous invasion into the wall and blood vessels; therefore, surgical salvage of the fallopian tube by extracting the products of conception will not always be curative.

Placentation in the fallopian tube.

The processes of implantation and placentation have been studied in 105 tubal pregnancies. Successful placentation occurred only with plicomural or mural implantations and in these the early development of the placenta occurred in the tube in exactly the same way as it does in the uterus, although tubal placentation was usually membranaceous in nature, possibly because of an inadequate blood supply. Invasion of the placental bed by interstitial extravillous cytotrophoblast occurred in the tube in the same manner as it does in the uterus whereas extravillous trophoblast invaded tubal vessels in the same fashion as it does the spiral arteries in the uterus. Subsequent development of the placenta in the tube differed from that in the uterus in so far as villous invasion of the tubal tissues, with consequent development of the placenta in the subserosa or on the serosa, was common. The ability of the blastocyst to implant in the tube with subsequent normal placentation indicates that these processes are purely a function of trophoblastic tissue, with maternal tissues playing only a passive role.