[A case of small-sized lung cancer complicated by sarcoidosis].

A woman in her seventies presented with bilateral hilar and mediastinal lymphadenopathy with high fluorodeoxyglucose (FDG) uptake by positron emission tomography (PET)-computed tomography (CT), small lung nodules, and uveitis. Mediastinoscopic biopsy yielded a histological finding of epithelioid granuloma and a diagnosis of sarcoidosis. A nodule, 1 cm in diameter, in the right middle lobe with moderate FDG uptake was deemed to be a sarcoidosis lesion. Steroid therapy for uveitis resulted in shrinkage of the hilar and mediastinal lymph nodes; however, 1 year later the nodule in the right middle lobe had enlarged to 2 cm in diameter. Right middle lobectomy was performed, and a histological diagnosis of lung squamous cell carcinoma was made. Six months later, right pretracheal lymphadenopathy with high FDG uptake was noted and was proved to be a metastatic squamous cell carcinoma by endobronchial ultrasound-guided transbronchial needle aspiration( EBUS-TBNA). After 7 courses of chemotherapy with docetaxel, the target lesion shrank and its abnormal FDG uptake disappeared. Small-sized lung cancer could be missed when complicated by sarcoidosis because the latter produces a background of multiple lesions, so careful diagnostic imaging and follow-up should be performed in patients diagnosed as having sarcoidosis.