Objective For lung cancer complicated with sarcoidosis, there are no exact features that indicate whether lymphadenopathy is metastatic. This makes the validity of surgery uncertain for clinicians. The aim of this study was to clarify the clinical features of pulmonary sarcoidosis complicated by lung cancer, especially from the viewpoint of evaluating lymphadenopathy.

Methods We retrospectively reviewed medical records from 2004 to 2013 at our institution, and 18 patients who were diagnosed with sarcoidosis and lung cancer were thus found to be eligible. We investigated the relationship between the clinical and pathological findings of their swollen lymph nodes.

Results Of 18 patients, 11 conducted surgery, and the postoperative pathological evaluation of swollen lymph nodes was done in 8 of the patients. Postoperative N factor in all these patients was 0, even though lymphatic metastasis had been suspected preoperatively because of the unbalanced distribution of lymphadenopathy or the accumulation of fluorodeoxyglucose.

Conclusion In patients with lung cancer complicated by sarcoidosis, the clinical assessment of the state of lymphadenopathy is difficult to make. However, as many of them tend to be benign, we suggest that surgical resection should be considered for a complete cure in the absence of any remote metastasis.