Variation in Major Pulmonary Fissures: Incidence in Fetal Postmortem Examinations and a Review of Significant Extrapulmonary Structural Abnormalities in Sixty Cases

A retrospective study of 1513 fetal postmortem examination reports from 1967 to 1996 yielded 35 cases with anomalous major pulmonary fissures (2.3%), to which a further 25 cases were added from fetal postmortem examinations performed between 1929 and 1966. Of 60 cases with anomalous fissures, 43 had an absent right horizontal fissure and 8 had a supernumerary left horizontal fissure; the remaining 9 showed various patterns in which one lung lacked major fissures. Histological examination in 29 cases did not reveal any additional pulmonary abnormality and pulmonary maturity was appropriate for gestational age. Additional malformations were present in 40 cases and these were frequently multiple, the most common being central nervous system, cardiovascular, and genitourinary system defects; notable heart malformations (10 cases); hydrocephalus (5 cases); and cystic renal dysplasia (4 cases). Chromosomal abnormalities were demonstrated in six cases although this figure does not reflect their prevalence, as many cases predate the availability of karyotyping. In seven cases, including three with polysplenia syndrome and one with situs inversus totalis, there was evidence of an underlying abnormality of left–right asymmetry, and in 13 cases there was documented pulmonary hypoplasia.