Reactive angioentotheliomatosis is a rare benign cutaneous vascular disorder. However, microscopical-ly it is important in the differential diagnosis of some vascular malignancies and malignant lymphoma. Two of our patients at the age of 62 and 79 years had a solitary, erythematous, 6 and 9 months slowly evolving asymptomatic lesions over the Ieft shoulder joint. Skin biopsies proved an endothelial proliferation in the dilated vessels corresponding to reactive angioendotheliomatosis. A joint disorder in the unilateral shoul¬der under the skin lesion could be considered as an etiological stimulus - in the form of progressive poly-arthritis in one patient and a serious osteoarthritis with synovitis in the other. In the first patient the lesi¬on disappeared up to 1 year after actinotherapy, the other patient was not treated, the lesion persisted and the patient died 4 years after the diagnosis because of cardiac failure.

        Key words: reactive angioentotheliomatosis - joint disorder - clinical picture - histological picture