Chest CT not reliable for distinguishing malignant tumors from benign pulmonary anomalies in kids: JAMA

USA: Chest computed tomography (CT) may not be accurate and reliable in distinguishing pleuropulmonary blastomas (PPBs) from benign congenital lung malformations in children, reports an article published in JAMA Network Open.

Congenital lung malformations (CLMs), a group of benign pulmonary anomalies, are rare conditions, estimated to affect 1 in 10,000 infants. Although the malignant transformation of benign CLMs is thought to be uncommon, a recent study confirmed that approximately 10% of cystic lung lesions may harbor cystic pleuropulmonary blastoma (PPB), a malignant and potentially lethal lung tumour associated with the DICER1 variant. PPB is a rare and aggressive malignant tumor in children. Diagnosis of PPB may be challenging due to its atypical presentations. PPB requires a prompt diagnosis and a multidisciplinary approach. Prognosis is closely related to the size of the tumour and metastatic status at the time of diagnosis. To date, the ability of CT to distinguish between benign CLMs and malignant cystic PPBs is not clear.

Engwall-Gill AJ., Johns Hopkins University School of Medicine, USA and colleagues conducted a multi-institutional case-control study of 40 children with cystic lung lesions, to assess the efficiency of chest CT in detecting malignant tumours among postnatally detected lung lesions in children.

Investigators used a consortium database of 521 pathologically confirmed primary lung lesions to assess diagnostic accuracy. CT scans from young children (median age, 7-8 months) with either a pathologically confirmed benign CLM or confirmed malignant PPB were reviewed independently in a blinded fashion by a cohort of trained pediatric radiologists. The main Outcomes were set as Accuracy, sensitivity, and specificity of CT in correctly identifying children with malignant tumors

Key findings of the study:

• The sensitivity of CT for detecting PPB was 58%, and the specificity was 83%.

• High suspicion for malignancy correlated with PPB pathology.

• There was poor interrater reliability and no significant difference in specific imaging characteristics between PPB and benign cystic lesions.

• The overall accuracy rate for distinguishing benign vs malignant lesions was 81%.

The authors conclude that chest CT, the current criterion standard imaging modality used to assess the lung parenchyma, may not be able to accurately and reliably distinguish PPB from benign congenital lung malformations in children. The study showed that CT scans have limited diagnostic accuracy and lack specific imaging characteristics that help to reliably discern PPB lesions from macrocytic congenital pulmonary airway malformations(CPAMs).

Operative management is recommended to confirm pathologic diagnosis in postnatally detected cystic lesions, the authors wrote.

Reference:

Engwall-Gill AJ, Chan SS, Boyd KP, et al. Accuracy of Chest Computed Tomography in Distinguishing Cystic Pleuropulmonary Blastoma From Benign Congenital Lung Malformations in Children. JAMA Netw Open. 2022;5(6):e2219814. doi:10.1001/jamanetworkopen.2022.19814