A 3-year-old boy dies in an automobile accident. At autopsy the right lung is markedly shrunken. Dissection shows that the right main stem bronchus ends blindly in nondescript tissue composed of rudimentary ducts and connective tissue. This finding represents an example of which of the following errors of morphogenesis?
Aplasia is the absence of an organ coupled with persistence of the organ anlage or a rudiment. Thus, aplasia of the lung refers to a condition in which the main bronchus ends blindly in nondescript tissue composed of rudimentary ducts and connective tissue. Dysraphic anomalies (choice C) are defects caused by the failure of apposed structures to fuse. Hypoplasia (choice D) refers to reduced size owing to the incomplete development of all or part of an organ. Examples include microphthalmia and microcephaly. Involution failures (choice E) reflect the persistence of embryonic or fetal structures that should involute at certain stages of development. A persistent thyroglossal duct is the result of incomplete involution of the tract that connects the base of the tongue with the thyroid.Diagnosis: Pulmonary aplasia
Aplasia
Atresia
Dysraphic anomaly
Hypoplasia
Genetics