A Case of Hybrid of Congenital Pulmonary Airway Malformation and Anomalous Systemic Blood Supply Presenting Elevated Serum Levels of Carbohydrate Antigen 19‐9

Congenital pulmonary airway malformations (CPAM) are rare congenital pulmonary anomalies in adults and are at risk of malignant transformation. CPAM lesions with abnormal systemic blood supply are considered hybrid lesions (HL). There are few cases of HL in adults. Here, we report a 44‐year‐old woman who presented with elevated serum carbohydrate antigen19‐9 (CA19‐9) levels and was diagnosed with HL with abnormal arterial blood flow from the celiac artery. After surgical resection, serum CA19‐9 levels immediately decreased to the normal range. Immunohistochemical staining of the resected lung tissue showed positive staining for CA19‐9 in the bronchiolar ciliated columnar epithelial cells. This report highlights that elevated serum CA19‐9 levels may be seen in HL, even in the absence of malignancy.