A 73-year-old woman presented with a chest X-ray finding of right lower lung field nodule, which was diagnosed by transbronchial lung biopsy (TBLB) as adenocarcinoma harboring epidermal growth factor receptor exon21 L858R. 18F-fluoro-2-deoxyglucose positron emission tomography (18FDG-PET) showed uptake in the nodule and the multiple mediastinal and hilar LNs. Cancer stage was determined as clinical T1bN3M0 stage SHB at another hospital. After a month of taking gefitinib (250 mg) daily, chest computed tomography (CT) showed a dramatic decrease in the size of the primary lesion from 20 to 10 mm, but the lymphadenopathy persisted (Fig. 1A-D). Because the treatment effect differed between the lymphadenopathy and primary lesion, she was admitted to our hospital for definitive LN diagnosis by EBUS-TBNA.
Physical examination on admission showed normal breath sounds and no superficial lymphadenopathy. Laboratory examinations showed the following: CEA, 4.3 ng/mL; SLX, 36 U/mL; soluble IL-2 receptor, 349 U/mL; angiotensin-converting enzyme, 14.6 U/mL; and Ca, 9.2 mg/dL. Chest X-ray and contrast-enhanced CT showed an irregularly shaped peripheral nodule in the right lower lobe and several bilateral mediastinal LNs with high FDG uptake on PET (Fig. 1E).
During EBUS-TBNA, the EBUS images showed homogeneous echogenicity and straight vessels in the LNs (Fig. 1F). Two samples were individually obtained from stations 4L and 4R by EBUS-TBNA. The pathological findings showed several non-caseating epithelioid granulomas, without tumor cells (Fig. 2A). Moreover, the PAB antibody detected small round bodies in the LNs (Fig. 2B), indicating that the lymphadenopathy was caused by sarcoidosis, not sarcoid reaction. Therefore, her stage was changed to clinical T1bN0M0 stage IA.
Following the discontinuation of the gefitinib course, right lower lobectomy and regional lymphadenectomy were immediately performed (Fig. 2C). Intraoperative findings showed non-coalescent and flat mediastinal LNs, showing the same pathological findings as those of the EBUS-TBNA LN samples. The final pathologic diagnosis was stage IA lung adenocarcinoma with sarcoidosis of the mediastinal LNs (Fig. 2D-F). There were no findings suggestive of sarcoidosis in the eyes, lung parenchyma, heart, skin, etc. The patient was followed up post operation for several years.