Pathology of asymptomatic, prenatally diagnosed cystic lung malformations

The management of asymptomatic congenital cystic lung malformations is controversial. Arguments for excision of asymptomatic lesions are the potential for infection and malignancy. Following antenatal detection, our institute performs a CT at 1month, clinic follow-up by 3months to discuss the controversial management, and offers surgery by 6months of age. We investigated the histopathology of asymptomatic lesions to determine whether there was evidence of subclinical infection or malignancy.

A retrospective review of prospectively collected antenatal congenital cystic lung malformations more than a 10year period (2005-2014) was conducted. Information was gathered from the antenatal registry and histopathology reports. Infection was defined by the presence of microabscesses or neutrophil/macrophage infiltration, as per histopathological criteria.

From the cohort of 99 patients, the study focused on 69 asymptomatic lesions. These cases comprised 34 congenital pulmonary airway malformations (CPAM), 15 pulmonary sequestrations (PS), and 20 hybrid lesions. Eighteen cases (26%) had microscopic disease - 16 cases of infection and 2 tumors. The infectious cases comprised 7 with microabscesses and 9 with neutrophil/macrophage infiltration. There were two cases of tumors, namely pleuropulmonary blastoma. These tumors were followed up by the oncology team with regular imaging until 3years of age and clinical review thereafter.

Twenty-six percent of antenatally detected, asymptomatic cystic lung malformations demonstrated either subclinical infection or malignancy. This information can be used for counseling parents and determining the method of treatment.