Introduction: The term sarcoid-like reaction (SLR) is used when non-necrotizing epithelioid-cell granulomas are detected without other criteria for systemic sarcoidosis (SA). SLR can occur, among others, in 4-14% of cancers. To avoid misdiagnosis, we present a case of sarcoid-like reaction in mediastinal lymph nodes to lung cancer. 

Clinical Case Description: A 67-year old woman, with a history of smoking 40 packet-years, applied for a screening program for lung cancer. The low dose CT Scan revealed a bilateral hilar and mediastinal lymphadenopathy and a 23 mm spiculated lesion in the left lung. Because the material collected from lymph nodes by EBUS-TBNA was non-diagnostic, a mediastinoscopy was performed. The biopsy revealed the non-caseating granuloma, sarcoidosis. The patient was admitted to the Outpatient Pulmonary Clinic to assess the severity of sarcoidosis. Apart from increased but similar signal activity in lymph nodes and a spiculated lesion in PET/CT, no sarcoid granuloma was detected in other organs. The metabolic activity of these nodes and spiculated lesion is similar, not allowing for different etiologies, although the spatial distribution of the lesions is somewhat unusual for a proliferative lesion in the left lung, with only the nodes on the contralateral side of the mediastinum affected. Suspecting the SLR to a lung cancer, a biopsy of the spiculated lesion was performed and squamous cell lung cancer grade 2 was detected. The patient was referred to the Thoracic Surgery Clinic, where a left upper lobectomy has been done. Histopathological examination of the resected tissue and mediastinal nodes confirmed the previous biopsy results. Cancer cells were absent in all examined nodes. The patient, without cancer and SLR recurrence, is under the care of a pulmonologist and oncologist.

Conclusions: SA is not always just sarcoidosis, because it can be a SLR in cancer, which if undiagnosed can lead to the patient's death.