Sarcoidlike reaction in patients with malignancy

PURPOSE: To determine the radiologic features, pathogenesis, and prognostic importance of sarcoidlike reaction in patients with malignancy. MATERIALS AND METHODS: Radiographs and computed tomographic (CT) scans of the chests of 10 patients with known malignancy and either concurrent or subsequent development of noncaseating granulomas (NCG) were reviewed and correlated with histopathologic reports and pertinent clinical data. RESULTS: Ten patients with malignancy were found to have either mediastinal or hilar lymph node enlargement (n = 4) or parenchymal lung disease (n = 6). The presumptive diagnosis was metastatic disease. In eight of 10 histopathologic specimens, no tumor was found, but innumerable NCGs were present. They were thought to be consistent with sarcoidlike reaction. In the other two specimens, only a small focus of tumor cells was found amidst innumerable NCGs. On CT scans of the chests, parenchymal lung disease took the form of either ground-glass attenuation (n = 1) or nodules following perivascular and peribronchial distributions (n = 5). CONCLUSION: Lymph node enlargement and parenchymal lung nodules may not indicate metastatic disease. Sampling of all abnormal areas may be helpful in staging the disease and in treating and determining the prognosis of patients. Likewise, the discovery of NCG does not necessarily indicate sarcoidosis and may represent sarcoidlike reaction.