A unique case of pulmonary minimally invasive mucinous adenocarcinoma arising from atypical goblet cell hyperplasia in the bronchial epithelium of a 9-year-old girl.

BACKGROUND

Pulmonary mucinous adenocarcinoma without congenital pulmonary airway malformation (CPAM) is extremely rare in pediatric patients. Here, we report a unique case of minimally invasive mucinous adenocarcinoma without CPAM in a child and provide a comprehensive review of the clinical, radiographic, and histopathological characteristics of the published literature.

CASE PRESENTATION

A 9-year-old girl presented with persistent cough and sputum production, raising suspicion of respiratory infection. Chest computed tomography (CT) revealed a solid nodule measuring 1.9 cm × 1.6 cm in the right lower lobe. Prenatal ultrasonography revealed no congenital lung abnormality. The patient subsequently underwent video-assisted thoracoscopic surgery (VATS) without postoperative complications. Histologically, a focal area demonstrated marked atypical goblet cell hyperplasia in the bronchial epithelium, which abruptly transitioned to mucinous adenocarcinoma, predominantly characterized by a lepidic growth pattern and extensive extracellular mucin accumulation. Pathological examination confirmed pulmonary minimally invasive mucinous adenocarcinoma, staged as pT1miN0M0. Next-generation sequencing (NGS) identified the KRAS G12D mutation. The patient remained well 11 months after resection and did not require additional treatment.

CONCLUSIONS

We demonstrated a novel stepwise progression originating from atypical goblet cell hyperplasia in the bronchial epithelium, rather than from the CPAM, in a pediatric patient. KRAS mutations may play a critical role in the development of pulmonary mucinous adenocarcinoma in pediatric patients.