ABSTRACT
A pulmonary mucinous cystadenocarcinoma is an extremely rare tumor that is considered to be a cystic variant of mucin-producing lung adenocarcinoma. We present a case of pulmonary mucinous cystadenocarcinoma in a 54-year-old woman. Chest CT scans showed a 4.3-cm-sized, lobulated, well-defined, and homogeneous mass in the right middle lobe with peripheral stippled calcifications that demonstrated low-attenuation with no enhancement after contrast administration; 18F-fluorodeoxyglucose (FDG) PET/CT demonstrated mild heterogeneous FDG uptake. The mass was diagnosed as adenocarcinoma with mucin production by transbronchial lung biopsy. Right middle lobectomy was performed, and the pathologic examination disclosed a pulmonary mucinous cystadenocarcinoma.