Intraplacental smooth muscle tumor: A case report

We present the second reported case of a smooth muscle neoplasm involving t he placental parenchyma. On gross examination, the tumor easily separated f rom the uterus and had a whorled cut surface with finger-like extensions in to the villous parenchyma, very similar to the previously described case. T he differential diagnosis included a primary smooth muscle tumor of the pla centa (placental leiomyoma), a primary uterine neoplasm incorporated into t he placenta, and a metastatic sarcoma. In this case, the infant was male, a nd the polymerase chain reaction technique demonstrated the presence of Y c hromosome gene in the placental parenchyma and its absence in the placental neoplasm. Thus, this neoplasm, despite its gross appearance of a primary p lacental tumor, actually represented an incorporated benign uterine leiomyo ma.