Buschke-Ollendorff syndrome in a 6-year-old patient: clinical and histopathological aspects of a rare disease.

Buschke-Ollendorff syndrome (BOS) is a rare genetic hereditary genodermatosis characterized by benign skeletal and cutaneous lesions. Skeletal alterations known as osteopoikilosis (OPK) or "spotted bone disease" are asymptomatic areas of sclerosing dysplasia. Two skin lesion patterns have been described because they may be of either elastic tissue (juvenile elastoma) or collagenous composition (dermatofibrosis lenticularis disseminata). We present the case of a 6-year-old male patient with yellowish papules that coalesced to form plaques localized on both thighs and on the upper limbs consistent with a connective tissue nevus (CTN) diagnosis. X-ray examination of the skeletal system revealed the presence of multiple small areas (measuring between 1 and 7 mm) of increased bone density (OPK) bilaterally. A skin biopsy was performed and did not show striking alterations in the number or dimension of the extracellular matrix fibers, but it showed mucin deposition between them, which is compatible with a CTN. This study reports on the clinical presentation and histological examination of this unusual disease.