Nineteen cases of malignant lymphomata were selected for study from a group of about 1500 collected cases of malignant lymphomata because they showed histological evidence of non-infectious epithelioid-cell granulomata in one or more tissues.In the 19 cases selected, 5 cases of systemic sarcoidosis, 4 cases of an associated malignancy, 1 pre-malignant condition, and 1 case of an auto-immune disease were found.This remarkable association of sarcoid reactions or sarcoidosis with malignant lymphomata and associated malignancies seems to justify speculation on the possibility of a common aetiological factor, e.g. in the form of an altered immune reaction.