Placental site trophoblastic tumor is a form of gestational trophoblastic disease, which is thought to arise from intermediate trophoblast.The tumor may secrete human placental lactogen, and result in a false-positive pregnancy test.A placental site trophoblastic tumor is a monophasic neoplasm of the implantation site intermediate trophoblast, and usually a benign lesion, which comprises less than 2% of all gestational trophoblastic proliferations. Preceding conditions include molar pregnancy (5%). Compared to choriocarcinoma or invasive mole, hemorrhage is less conspicuous and serum β-HCG level is low, making early diagnosis difficult. Immunohistochemistry: Often stains with hPL, keratin, Mel-CAM, EGFR. Treatment
Because chemotherapy is ineffective; the patient should undergo hysterectomy. Prognosis
10–20% of cases metastasize leading to death. References


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Dipygus is a severe congenital deformity where the body axis forks left and right partway along the torso with the posterior end (pelvis and legs) duplicated. Myrtle Corbin was a dipygus; she married and had five children. In human cases, the inner two of the four hindquarters develop much smaller than normal. This is a type of "teras catadidymum" ("monster twinned below"). Another sort of deformity with extra legs can happen from a degenerated conjoined twin, as may have happened with Frank Lentini with his third leg. Signs
Dipygus manifests as duplicated lower limbs and could include additional organs or bodily structures. Causes
Dipygus is caused by genetic, environmental, or teratogenic factors. It occurs early in intrauterine life. == References ==