Placental mesenchymal dysplasia (PMD), characterized by an enlarged and thickened placenta with multiple hypoechoic cystic spaces, frequently leads to a poor infantile/fetal outcome. Here, we describe a case of PMD involving an infant delivered at term with a good outcome. The fetus was male, and the proportion of the PMD lesion to the entire placenta remained constant: the PMD lesion did not enlarge. Given what is known about the pathogenesis of PMD with its association with vascular endothelial growth factor-D (VEGF-D) encoded by an X-linked gene and androgenetic/biparental mosaicism, which is consistent with female dominancy and a poor outcome, we suggest that a male sex of the fetus and non-progressing PMD may have been associated with this good outcome.