Ectopic neuroglial tissue associated with intrapulmonary congenital cystic adenomatoid malformation

BACKGROUND: Few cases of ectopic neurological tissue have been reported in the lung. The aim of the present study was to give a brief overview of these cases and to examine an additional case of intrapulmonary neuroglial heterotopia. We have identified only sixteen similar cases in the literature. CASE DESCRIPTION: The object of our study was a male fetus of Asian parents at the 23rd week of gestation, in which ultrasound tests revealed the presence of anterior encephalocele. Routine postmortem examination of lung samples showed neuroglial tissue and a congenital adenomatoid cystic malformation of type II. The lesion was made up of multiple small cysts lined with columnar or ciliated cuboidal epithelium. A possible link between adenomatoid malformation and intrapulmonary neurological tissue has not so far been reported in the literature. Immunohistochemical analysis showed the presence in the pulmonary parenchyma of neuronal cells (neuron-specific enolase positive), astrocytes (glial fibrillary acidic protein positive) and intra-alveolar squamous cells (citokeratines positive), indicative of fetal aspiration of amniotic fluid. CONCLUSIONS: There are several possible explanations for the presence of intrapulmonary neuroglial heterotopia: fetal aspiration, neural crest migration defects or vascular embolization with implantation. However, in the view of the microscopic findings and at the same time recognizing the intrapulmonary aspiration of amniotic fluid, the authors maintain that the most likely explanation for the heterotopia is that of consequential multiple malformations. Moreover neuroglial ectopy and cystic adenomatoid congenital malformation of the lung could have appeared simultaneously, due to embryologic insult between the 4th and the 20th week of gestation.