Mucinous colloid adenocarcinoma of the lung with lymph node metastasis showing numerous punctate calcifications.

Mucinous colloid adenocarcinoma (MC) of the lung represents a rare but distinctive variant of primary pulmonary adenocarcinoma, which usually shows favorable prognosis. We describe the case of a 70-year-old man who had a well-demarcated mass with numerous punctuate calcifications in the right middle lobe. Four months after surgery, multiple bone metastases were found and the poor prognosis was suggested. This is the first case of primary pulmonary MC with the characteristic imaging findings and the rare aggressive clinical feature.