[Severe and extensive algodystrophies and malignant tumors. Apropos of 4 cases].

The authors report on 4 cases of particularly severe and extensive reflex neurovascular dystrophy, whose clinical course was marked by the onset of a malignant tumor, without any sign of improvement in the reflex neurovascular dystrophy, despite various therapeutic regimens, until the patient's death from malignancy. At this time, the authors compiled a total of 63 case reports (4 of which were reported) and have proposed a classification to differentiate 4 types of disorders in combination according to whether there is a very probable, probable, or possible link or whether the combination is strictly a coincidence. The pathogenic mechanism remains a mystery, when a link is observed; but it never corresponds to criteria to describe a paraneoplastic disorder. Finally, the authors insist on the practical value of detecting this combination, even if due to chance: in order to systematically detect cancer in the presence of any reflex neurovascular dystrophy, and especially to be conscious of a possible reflex neurovascular dystrophy, besides possible metastatic lesions, in the presence of osteoarticular pain present in a patient with cancer. Such a diagnosis, although difficult to realize, has great prognostic and therapeutic interest.