osteoma cutis

progressive dermal ossification during childhood, with hard, round to irregular nodules representing islands of heterotopic bone within the dermis or subcutis, followed by coalescence of the lesions into plaques, and later by invasion of deep connective tissues. It may be sporadic or inherited as an autosomal dominant trait; the affected gene encodes a subunit of the G protein stimulating adenylyl cyclase. Called also progressive osseous heteroplasia.