Osteoma cutis associated with disordered ossification of the clavicle. A case report

Congenital multiple osteomas of the skin associated with disordered ossification of the clavicle occurred in a four-year-old boy. There were no clinical and laboratory findings of pseudohypoparathyroidism, pseudopseudohypoparathyroidism, or fibrodysplasia ossificans progressiva in this case. The clavicular bony mass was excised in segments. Samples of the cutaneous osteomas were removed for histologic study. On microscopic examination, the specimen from the clavicle consisted of trabecular bone in hyaline cartilage, resembling enchondral ossification, but the specimen from the osteoma cutis revealed a mature membraneous bone without cartilage.