The prenatal recognition of an echogenic lung mass commonly is associated with problems of differential diagnosis. The following lesions may present with echogenic lung masses,2:

• Intrathoracic lung sequestration

• Cystic adenomatoid tumor of the microcystic form

• Tracheal obstruction (both lungs completely involved)

• Bronchial atresia

• Congenital lobar emphysema

Prognosis

Among 16 intrathoracic lung sequestrations in 14 fetuses with prenatally demonstrated feeding vessels arising from the aorta,

• 2 fetuses required placement of a thoracoamniotic shunt

• 4 fetuses completely lost evidence of a mass

Spontaneous involution has been demonstrated for:

• intrathoracic sequestration in fetuses[3],[4],1,2,[5],,[7] and newborns[8],

• intraabdominal sequestrations[9]

• bronchial plugs[10]

• type II congenital cystic adenomatoid malformation6

Pulmonary sequestrations tend to have a favorable outcome; many regress prenatally, those who persist can be treated postnatally, and the only one that require intervention are those with hydrops or effusion. The presence of mediastinal shift or even diaphragmatic inversion does not necessarily predict poor outcome. Only those fetuses with hydrops have poor outcome.

Case

This fetus was seen first at 20 weeks when a echogenic lung mass was seen with a vascular supply arising from the descending thoracic aorta. Note the mediastinal shift and subtle diaphragmatic inversion.

The lung mass displaces the heart and everts the diaphragm.

The mass surrounds the aorta and gets a feeding vessel from the descending aorta

A repeat scan at 24 week demonstrate some reduction of the mass

The feeding vessel.

At 28 weeks the mass had disappeared and the newborn was asymptomatic.

References

[1] Lacy DE, Shaw NJ, Pilling DW, Walkinshaw S Outcome of congenital lung abnormalities detected antenatally. Acta Paediatr 1999 Apr;88(4):454-8

[2] Lopoo JB, Goldstein RB, Lipshutz GS, Goldberg JD, Harrison MR, Albanese CT Fetal pulmonary sequestration: a favorable congenital lung lesion. Obstet Gynecol 1999 Oct;94(4):567-71

[3] Barret J, Chitayat D, Sermer M, Amankwah K, Morrow R, Toi A, Ryan G The prognostic factors in the prenatal diagnosis of the echogenic fetal lung. Prenat Diagn 1995 Sep;15(9):849-53

[4] Bromley B, Parad R, Estroff JA, Benacerraf BR Fetal lung masses: prenatal course and outcome. J Ultrasound Med 1995 Dec;14(12):927-36

[5] Petrikovsky B, Schneider EP, Klein VR, Gross B Clinical significance of echogenic foci in fetal lungs. J Clin Ultrasound 1997 Nov-Dec;25(9):493-5

[6] Winters WD, Effmann EL, Nghiem HV, Nyberg DA Disappearing fetal lung masses: importance of postnatal imaging studies. Pediatr Radiol 1997 Jun;27(6):535-9

[7] King SJ, Pilling DW, Walkinshaw S Fetal echogenic lung lesions: prenatal ultrasound diagnosis and outcome. Pediatr Radiol 1995;25(3):208-10

[8] Garcia-Pena P, Lucaya J, Hendry GM, McAndrew PT, Duran C Spontaneous involution of pulmonary sequestration in children: a report of two cases and review of the literature. Pediatr Radiol 1998 Apr;28(4):266-70

[9] Daneman A, Baunin C, Lobo E, Pracros JP, Avni F, Toi A, Metreweli C, Ho SSY, Moore L Disappearing suprarenal masses in fetuses and infants. Pediatr Radiol 1997 Aug;27(8):675-81

[10] Achiron R, Strauss S, Seidman DS, Lipitz S, Mashiach S, Goldman B Fetal lung hyperechogenicity: prenatal ultrasonographic diagnosis, natural history and neonatal outcome. Ultrasound Obstet Gynecol 1995 Jul;6(1):40-2