Coexistence of sarcoidosis and malignant disease: causality or coincidence?

A review of 131 cases of coexistent sarcoidosis and malignancy indicates that this association is not fortuitous: 1) A nonrandom sample of tumor types is observed. 2) The chronic active type of sarcoidosis is involved much more often than the subacute self-healing type. 3) The temporal relationship between sarcoidosis and subsequent malignancy is not a random one, at least not in malignant lymphoproliferative disease, in which sarcoidosis almost invariably precedes malignancy. 4) The observed incidences of malignant lymphoproliferative disease and of lung cancer are significantly higher than expected. The association of sarcoidosis and malignant lymphoproliferative disease is so constant that the existence of a sarcoidosis-lymphoma syndrome is suggested, in which the chronic active type of sarcoidosis appears to be responsible for an increased risk of malignant transformation of lymphoid cells.