Intravascular histiocytosis associated with rheumatoid arthritis

Various dermatoses associated with rheumatoid arthritis (ra). have been described recently, a specific skin lesion termed “intravascular histiocytosis” has been proposed as a new entity among these dermatoses. we report a 58-year-old man with an 8-years history of ra who presented with numerous variable sized erythematous papules, plaques and nodules on the v region of the neck, right femoral region and bilateral shins. histopathological examination of these lesions demonstrated intraluminal aggregates mainly composed of cd68-positive histiocytes in markedly dilated vessels. in addition, after 6 months of follow-up, the patient was diagnosed as kaposi sarcoma (ks) for another skin lesion. we discuss the pathogenesis of this association and compare with other cases reported in the literature.