[Multicentric reticulohistiocytosis (lipoid dermato-arthritis). A radiologic study of 3 cases].

The authors report their experience with 3 cases of multicentric reticulohistiocytosis observed over 6 years of outpatient radiological practice. The condition presents with the following radiological patterns: 1) clear-cut erosions of the articular surfaces, especially in the distal interphalangeal joints of the hands and in the metatarso-phalangeal joints of the feet, with symmetrical distribution (not necessarily); 2) osteolytic punched-out areas in the epiphyseal spongiosa, ranging in size from 1 mm to over 1 cm; 3) no osteoporosis, no osteo-proliferative or periosteal reactions, not even in the presence of large osteoarticular destructions; 4) frequent atlanto-epistropheal subluxation; 5) articular ankylosis at the sacroiliac joints only. The association of the above patterns and the relatively benign clinical course distinguish multicentric reticulohistiocytosis from rheumatoid arthritis, psoriasis arthritis, erosive osteoarthritis, and gout. A reliable diagnosis can be suggested on the basis of radiological findings alone, even before cutaneous or mucosal lesions appear--which are, at any rate, not sure to appear and typical of nails only. An unquestionable diagnosis can be made at histology of synovial and/or cutaneous nodules. Multicentric reticulohistiocytosis is considered an uncommon condition (nearly 100 cases in international literature to 1989); the authors believe it to be commoner though often misdiagnosed as a "variant of rheumatoid arthritis".