Pseudotumors of the placenta

The placenta is one of the most common gross pathology specimens encountered by surgical pathologists, yet primary tumors are exceptionally rare and even rarer are entities with the potential to mimic malignancy. There are many nonneoplasticmass forming lesions in the placenta that are important to be aware of as many of these can be associated with adverse outcomes in the mother and fetus. Also important are entities which may be observed microscopically in the placenta and potentially confused as a malignancy. Knowledge of these potential pitfalls is essential to avoid making an incorrect diagnosis and causing undue alarm.