Sarcoid-Like Lesions Mimicking Pulmonary Metastasis: A Case Series and Review of the Literature

Abstract

Background: The association of sarcoid-like lesions and malignancy is well described. Nonetheless, pulmonary lesions in malignant disease are typically presumed metastatic, and do not routinely receive histological validation. Here, we report on pulmonary sarcoid-like lesions identified in patients with a primary malignancy where pulmonary metastatic disease was suspected. Methods: Patients who underwent thoracic surgical procedures for confirmation or treatment of suspected pulmonary metastasis were retrospectively analysed. Results: In 8/186 patients (4.3%), histology revealed sarcoid-like lesions. In these cases, there were no clinical symptoms suggestive of sarcoidosis. All underlying primary malignancies in the sarcoid-like patients were treated with curative intent. The median age of patients with sarcoid-like lesions was 46.3 years (range 26–61). The median interval between primary diagnosis of malignancy and diagnosis of pulmonary lesions was 188 days (range 0–794), with thoracic surgical intervention performed at a median of 250 days (range 183–675). FDG-avidity was demonstrated in the sarcoid-like lesions in 2 out of 3 patients who underwent PET-CT. Conclusion: Sarcoid-like lesions may be challenging to identify and can mimic pulmonary metastases. Therefore, considering sarcoidosis as a differential diagnosis whenever first pulmonary metastasis is suspected is warranted. Carefully considered, histological validation of initial suspected pulmonary metastasis may avoid subsequent over- or undertreatment.