Pulmonary mucinous cystadenocarcinoma: report of a case and review of the literature.

A case of primary mucinous cystadenocarcinoma of the lung is presented. The patient was a 42-year-old woman with a 5-cm left lung mass. Left lower lobectomy was performed and analysis of a frozen section revealed mucinous cystadenocarcinoma. The tumor was a fibrous, walled cyst containing abundant mucinous material. Sparse groups of malignant cells were microscopically observed in pools of mucin; thus, the tumor resembled mucinous cystadenocarcinoma that occurs in the ovary, appendix, or pancreas. The tumor we found is a very rare intrapulmonary neoplasm that is differentiated from a metastatic lesion and mucinous bronchoalveolar carcinoma by its very different clinical course and prognosis.