A 35 month old girl had suffered from painful joint contractures of the whole body since a few months after birth, and she gradually developed numerous periarticular and subcutaneous nodules, hoarseness, swallowing difficulty with recurrent respiratory infections, nystagmus, and mental and developmental retardation. She was misdiagnosed as having juvenile rheumatoid arthritis at several university hospitals. Serologic studies for rheumatoid arthritis were all negative. Radiologic findings of the whole body showed osteoporosis and bony erosions; on brain CT the brain was diffusely atrophied. On cine-esophagography barium refluxed into the nasopharynx. Light microscopically, the reticular dermis and subcutis were markedly thickened with hyalinized sclerotic collagen bundles. There were interstitial and perivascular aggregates of foamy histiocytes which were positive for CD-68 immunostaining. On electron microscopy, foamy histiocytes were packed with numerous membrane-bound inclusions having C-shaped or worm-like profiles in addition to many myelin figures, occasional lipid droplets and rare banana-like bodies.