Sarcoidosis and the occurrence of malignant diseases

Whereas the association between sarcoidosis and malignant diseases has been well described, it remains controversial whether this association is merely a coincidence or the consequence of a common pathophysiologic mechanism. We investigated the incidence of malignancies in a large cohort of patients with sarcoidosis from a German University Hospital. Patients with a malignant disease were identified in a retrospective analysis of a cohort of 425 patients with sarcoidosis at the Medical Center of the University of Heidelberg. The type of malignancies and the onset before, concomitant or after sarcoidosis were analyzed. Sixty-one patients with a malignant disease were identified in our cohort of 425 patients with sarcoidosis. Among them, there were 18 patients with malignant lymphoma, 13 with breast cancer and 5 with cervical cancer. Malignant lymphoma was diagnosed up to 30 years after sarcoidosis with a median of 6.9 years. Breast or cervical cancers were diagnosed up to 20 years before or after sarcoidosis, and the median was 0.0 years. A high prevalence of B-cell lymphoma, breast and cervical cancers was found in our sarcoidosis cohort. In most patients, B-cell lymphoma was diagnosed many years after chronic sarcoidosis. In contrast, the diagnosis of breast or cervical cancer was evenly distributed before, around and after the diagnosis of sarcoidosis. Our hypothesis is that the immune dysregulation which persists during or after chronic sarcoidosis might represent a contributing factor for the development of B-cell lymphoma.