congenital adenomatoid malformation of the lungs in a calf

A 7-month-old fetal calf had a diffuse, solid adenomatoid malformation of the left diaphragmatic lobe of the lungs. The malformation consisted of a large white mass with a lobular pattern. The lobules had a sponge-like structure without any cysts and contained dilated bronchioles, lined by a single layer of epithelial cells and a layer of elastic fibres. There were neither cartilaginous rings nor muscle fibres. The anomaly was associated with generalized fetal hydrops, oedema of the fetal membranes, and indications of hydramnion or hydrallantois.