Fetal laryngeal obstruction: sonographic detection

Abstract

A patient was referred at 21 weeks' gestation for unexplained fetal lung hyperechogenicity and ascites. Amniocentesis was normal. Fetal lung biopsy was consistent with the clinical diagnosis of cystic adenomatoid malformation of the lungs. However, autopsy of the stillborn infant demonstrated a cartilaginous bar, causing total laryngeal obstruction. The distinctive ultrasonographic appearance is presented.

Outcome of the Prenatally Diagnosed Congenital Cystic Adenomatoid Lung Malformation: A Canadian Experience

“…Even after removal of the lesion, we often find radiological and pathological elements that overlap for all congenital lung malformations. Histological criteria typical of CCAM are often present in cases of bronchial or laryngeal atresia [4,31], as we saw in 1 case. This overlap raises questions regarding the etiology of congenital lung malformations; it is believed that a partial or transient obstruction is responsible for lobar emphysema [2], and the same mechanism has been proposed for CCAM [4].…”

“…We therefore believe that a period of observation in utero is essential. If TAB seems a logical choice in cases of severe hydrops [8,31] where fetal intervention is contraindicated or refused, it should not be recommended simply because a mass is large, microcystic or causes severe mediastinal shift. Fetal therapy may consist of different approaches.…”

Cystic adenomatoid malformation of the lung: clinical evolution and management

“…Moreover, spontaneous regression has also been recently reported in fetuses with polyhydramnios or ascites [12]. Laryngeal obstruction has been observed to produce a prenatal ultrasonographic and histological appearance similar to CAML [2,6]. Therefore, it has been suggested that this association could explain the apparent resolution of some cases of CAML [12] and Dumez et al [4] reported such prenatal unpredictable``disappearance'' in approximately 21% of cases (3 of 14 cases).…”

“…This lends support to the hypothesis of a possible correlation between the prenatal image and the clinical disappearance or resolution of the lesion. Maybe the microcystic appearance could be à`f alse image'' related to a temporary laryngeal obstruction [2,13] or a simple inahalation of vernix caseosa. In one case of our series, who underwent prenatal resolution, a remarkable amount of vernix caseosa was clearly evident in the amniotic¯uid.…”

“…However, neither is it a routine procedure nor can it be useful in making a decision for surgery. In fact, it must be taken into account that a temporary laryngeal obstruction may produce a similar histological appearance [2,6] and that CAML might resolve postnatally. Approximately 26% of the surviving infants in a series with prenatally diagnosed CAML did not undergo surgery because of either absence of symptoms or resolution of pathology [12].…”