Lambda – Panda sign is typically seen in
**Core Concept**
The Lambda-Panda sign is associated with a characteristic ultrasound finding in pregnancy, which helps in diagnosing a specific condition. This sign is related to fetal anatomy and is an important marker for obstetricians.
**Why the Correct Answer is Right**
The Lambda-Panda sign is typically seen in cases of twin-to-twin transfusion syndrome (TTTS), a condition that occurs in monochorionic diamniotic (MCDA) twin pregnancies. In TTTS, one twin (the recipient) receives more blood and nutrients than the other twin (the donor), leading to an imbalance in their growth and development. The Lambda-Panda sign is a result of the unequal growth and development of the twins, where the donor twin has a smaller head circumference and a more prominent lambda sign (a triangular area of echogenicity at the intersection of the intertwin membrane and the placental cord insertion site). The recipient twin has a larger head circumference and a more pronounced panda-like appearance on ultrasound, with a larger amount of echogenic bowel and placental thickness.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the Lambda-Panda sign is not typically associated with other conditions such as twin anemia-polycythemia sequence (TAPS) or discordant fetal growth in dichorionic diamniotic (DCDA) twin pregnancies.
**Option B:** This option is incorrect because the Lambda-Panda sign is not a characteristic finding in singleton pregnancies or other types of multiple gestations.
**Clinical Pearl / High-Yield Fact**
The Lambda-Panda sign is an important marker for TTTS, and early recognition of this sign can help obstetricians to diagnose and manage this condition promptly, thereby improving outcomes for the twins.
**Correct Answer: C. Twin-to-twin transfusion syndrome (TTTS)**