Mixed invasive mucinous and non-mucinous adenocarcinoma of the lung with hematogenous metastases to multiple organs

Mixed invasive mucinous and non-mucinous adenocarcinoma is a rare variant of lung adenocarcinoma. In pure invasive mucinous adenocarcinoma, multilobar and bilateral involvement are common, and extrathoracic metastasis is rare. Here, we report a case of mixed invasive mucinous and non-mucinous adenocarcinoma with distant metastasis to multiple organs without marked enlargement of the primary lung lesion. The pathological findings indicated high tumor invasiveness and the patient died 10 months after diagnosis despite chemoimmunotherapy. Further investigations are necessary to elucidate the clinical characteristics and appropriate management of mixed invasive mucinous and non-mucinous adenocarcinoma.