"Placental polyp": light microscopic and immunohistochemical observations

Placenta Increta Presenting as Retained Placenta: A Report of 3 Cases

OBJECTIVES

Morbid adherence is a risk factor for retained placenta (RP). We encountered three cases of placenta increta presenting clinically as delayed postpartum hemorrhage.

METHODS

This was a retrospective study of three cases of placenta increta presenting as RP.

RESULTS

One "routine" term placenta had heavy bleeding 2 weeks later; one missed abortion at 16 weeks with fetal and placental tissue submitted, had heavy bleeding 6 weeks later; and one elective abortion (no tissue submitted), had delayed postpartum bleeding leading to a curettage with blood only, then 6 weeks later a hysterectomy for menorrhagia. All 3 pathology specimens showed necrotic villi. However, all three also showed myometrium with keratin-positive interstitial trophoblasts in a zone of damaged myometrium, consistent with increta. All three cases had basal plate myofibers (BPMF) in the placenta, with BPMF recurrence in the two cases with another pregnancy.

CONCLUSION

RP may be a presenting clinical manifestation of placenta increta.

Placental polyp: a rare cause of iron deficiency anemia

Placental polyps are defined as pedunculated or polypoid fragments of placenta or ovular membranes retained for an indefinite period of time into the uterus after abortion or child birth. An important cause of retention is placental accretism, an abnormal adherence of the placenta into the uterine wall. Chronic cases are rarely reported in the literature. In these cases, the placental retention in the immediate postpartum is not followed by heavy bleeding what makes the diagnosis challenging. We report a rare case of iron-deficiency anemia in a multiparous 29-year-old female patient two years after the last delivery. She sought medical care with clinical symptoms of anemia and recent menses alterations. There was no history of abortion. On gynecological examination, there was a twofold enlarged uterus, and the pelvic ultrasound revealed an image compatible with an endometrial polyp. She underwent open hysterectomy because of uncontrollable bleeding followed by hypotension after curettage. The histolopathologic examination revealed a partially hyalinized and necrotic placental polyp.

The placental site nodule: an immunohistochemical study

The placental site nodule and plaque (PSN-P) is a recently described, benign proliferation of intermediate trophoblast cells (ITs) in the endometrium or endocervix occurring after an intrauterine gestation. We performed an extensive immunohistochemical study of 11 cases of PSN-P. Cytokeratins (AE1/AE3 and MAK 6) were strongly positive in all cases stained. Epithelial membrane antigen (EMA) was positive in all cases, in 5% to 75% of lesional cells. Expression of human placental lactogen (hPL) was weak and focal, and a minority of cases were positive for human chorionic gonadotropin (hCG). More helpful in identifying the trophoblastic nature of the lesion was pregnancy-specific beta-1 glycoprotein (SP1), which was present in 100% of cases, and placental alkaline phosphatase (PLAP), present at least focally in 90% of cases stained. Vimentin was strongly positive in all cases stained. The presence of vimentin, SP1 and PLAP in PSN-P has not been documented previously. In our opinion cytokeratin, vimentin, and SP-1 are the most important monoclonal antibodies to aid in the differential diagnosis of PSN-P.