Term
| how can infections occur in the placenta? |
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Definition
| ascending through the birth canal or transplacentally through the hematogenous route. *ascending are more common and are usually bacterial in origin - may lead to premature rupture of the membranes and preterm delivery. |
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Term
| how does the placenta appear if infected? |
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Definition
| the *amniotic fluid may be cloudy w/purulent exudate. the *chorion-amnion may have a PMN (neutrophil) infiltrate w/edema and congestion of the vessels. there may also be *inflammation of the umbilical vessels. |
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Term
| what infections are more common to the placenta? |
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Definition
| TORCH infections: toxoplasmosis, rubella, cytomegalovirus, herpes simplex, may have syphilis, tuberculosis, or listeriosis |
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Term
| why is chronic villitis of the placenta important? |
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Definition
| chronic villitis may be associated w/intrauterine growth retardation, still births, and chronic chorioamnionitis. the cause is unknown, but may be linked to unknown organisms/abnormal immune activity. this is found in 1-9% of all placentas. |
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Term
| how can listeria infection affect the placenta? |
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Definition
| this can cause cause necrotizing villitis histologically: hazy inflammation/necrosis. |
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Term
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Definition
| acute inflammation of the umbilical cord, a sign of a fetal inflammatory response. this begins as a discrete multifocal process which coalesces as it progresses. |
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Term
| what is a placental infarct? how does it appear? |
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Definition
| an area of villous necrosis due to local obstruction of the maternal uteroplacental circulation. a fresh infarct will appear grossly as dark red and firmer than the surrounding tissue and histologically - crowding of villi w/congestion of the villous vessels. an older lesion will appear as a hard, white mass of granular appearance and ghost villi. |
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Term
| what causes a placental infarct? what affect does it have on the baby? |
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Definition
| placental infarcts may be due to abruptio placentae and may increase in number/severity in cases of preeclamptic toxemia, HTN, and Rh incompatibility. a high number of placental infarcts are associated w/a high incidence of neonatal asphyxia, low birth wt and intrauterine demise. |
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Term
| what is gestational trophoblastic disease? |
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Definition
| a group of diseases related to normal/abnormal gestation, a common denominator of which is the proliferation of trophoblast. there are common, partial, and invasive moles and choriocarcinoma. |
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Term
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Definition
| a complete mole is caused by abnormal gametogenesis and fertilization, where the nuclei contain only paternal chromosomes and cytoplasmic DNA is maternally derived. most cases have a normal chromosomal number and are 46xx. there is a greater incidence in south-east asia |
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Term
| how does a complete mole present? |
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Definition
| *no identifiable embryo, cord, or amniotic membranes since the embryo dies so early in development. the uterus is *disproportionately large for the stage and villi of the placenta may invade the myometrium. *serum hCG levels continue to rise after the 14th wk. evidence of toxemia/preeclampsia is often found (HTN, edema, albuminuria) and hyperthyroidism can develop from the stimulating effects of the molar tissue. vaginal bleeding may be present, and grossly a complete mole appears like "a bunch of grapes" due to swollen villi. histologically: trophoblastic hyperplasia, vesicular swelling, and hGC and PLAP are present in tissue. |
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Term
| what genetics are associated with complete mole? |
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Definition
| complete moles *lack p57* which is a cell cycle inhibitor seen in partial moles. there is also expression of myc, ras, and sis. |
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Term
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Definition
| this is often associated with the *presence of an embryo and accounts for 15-33% of all moles. volume of the placental tissue is relatively normal w/some vesicular villi. many of the villi have an *irregular scalloped outline w/vessels containing *nucleated fetal RBCs. fibrosis of the villous stroma is common. trophoblastic proliferation is seen, same as a complete mole. serum hCG levels are elevated, but tend to be relatively low and risk of development of choriocarcinoma is low. |
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Term
| what genetics are associated with partial moles? |
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Definition
| partial moles are positive for p57 (which complete moles are negative for) and most are triploid (69xxx or 69xxy) or possibly tetraploid (while complete moles are diploid). |
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Term
| what is an invasive mole? |
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Definition
| a mole, usually a complete mole, where the *villi penetrate deeply into the myometrium and/or its blood vessels - which may lead to significant hemorrhage or uterine perforation. vascular invasion may cause trophoblastic nodules to travel outside the uterus to the lungs, brain, or spinal cord hematogenously and can cause hemorrhage. it is differentiated from a usual mole is that it invades the myometrium and differentiated from a choriocarcinoma in that it contains villi. |
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Term
| what is a choriocarcinoma? |
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Definition
| the most aggressive form of gestational trophoblastic disease, usually occurring w/a *complete mole. a soft red, hemorrhagic, nodular tumor mass with clusters of cytotrophoblast separated by masses of syncytiotrophoblast resulting in a *dimorphous pattern (2 distinct cell types). *villi are absent, and cells are positive for hCG and sometimes keratin. hemorrhage and necrosis are present in varying degrees. if untreated it can be very aggressive and metastasizes via the hematogenous route to the bowel, lung, brain, liver and kidney - but w/appropriate therapy the cure rate is high (early recognition/aggressive chemotherapy). |
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Term
| what is a placental site trophoblastic tumor (PSTT)? |
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Definition
| this rare form of trophoblastic disease presents as a myometrial mass which may be well or ill defined (invades the myometrium and blood vessels). PSTTs contain *large trophoblastic cells w/abundant eosinophilic cytoplasm and nuclear polymorphism*. uterine penetration is deep and perforation can occur. 75% follow a normal pregnancy and 5% have had a previous molar pregnancy. |
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