Fig. 1.

Representative gross and microscopic appearance of TAPS placenta.

A. Fetal surface following removal of the intertwin membrane and injection of the chorionic vasculature. Vascular injection highlights the near-complete separation of the choriovascular beds. A single minuscule artery-to-artery anastomosis is shown by arrow. Color code: Left twin: artery: red, vein: green; right twin: artery: red, vein: yellow (venous bed only partially filled due to vascular disruption).

B. Maternal surface demonstrating marked color (redness) discordance with sharp demarcation of polycythemic (left) and anemic (right) territories. C-D. Representative micrographs of plethoric and pale placental parenchyma, respectively. Insert: ×600 magnification of Fig. 1D showing circulating erythroid precursors (hematoxylin-eosin staining, original magnification ×200. Scale bar = 20 μm)