[Lcoc-regional sarcoid reaction. Sarcoidosis and malignant tumors].

On the basis of eight cases, the authors consider the relationship between sarcoidosis and malignant tumours. The development of a malignant tumour simultaneously or during the years following the onset of sarcoidosis is a rarely seen phenomenon. Only seven cases out of 580 of sarcoidosis were noted in this series. The absence of comparison with control groups of similar age and sex as well as of prolonged observation in a certain number of sarcoidosis patients cured or lost from sight prevents any valid statistical assessment, but the average age (51 years) of the patients at the time of discovery of the tumour is that of the risk of spontaneous development of carcinoma. Thus the association "sarcoidosis-malignant tumour" would appear to be purely a question of chance. The finding of sarcoid-type histopathological reactions in lymph nodes involved in the spread of a malignant tumour often represents the residual expression or reactivated by the tumour of old sarcoidosis which had gone unnoticed. The development of a malignant tumour is capable of provoking in old sarcoidosis patients a late recurrence of the disease.