Intrapulmonary neuroglial heterotopia.

Nonteratomatous intrapulmonary neuroglial heterotopia not associated with birth trauma or frank vascular embolization has been described rarely. This article briefly reviews the literature, and presents two additional cases of intrapulmonary neuroglial heterotopia. We found 14 cases in the literature. Twelve of these cases had central nervous system disruption, where neuroglial elements were in direct contact with amniotic fluid. Several hypotheses have been proposed, including fetal aspiration of detached neural fragments within amniotic fluid, neural crest migration defects, and vascular embolization with implantation. Of our two cases, one represents the first occurrence where central nervous system abnormalities were secondary to mechanical disruption, rather than to a primary neural tube defect. Our second case represents the youngest documented occurrence (17 weeks gestation) of intrapulmonary neuroglial heterotopia. Additionally, immunohistochemical studies were performed on these lesions, the results of which favor their neural origin. We present these findings and suggest they support the aspiration mechanism for neuroglial heterotopia in lung tissue.