Summary
A case of heterotopic bone formation in the scalp of a 39 year old woman is presented, with the relevant radiological and pathological findings.
A review of the previous literature is given and the lesion is discussed with reference to other examples of heterotopic ossification.
Factors such as trauma, ischaemia and inflammation are seen to be important predisposing factors in the formation of bone at abnormal sites.
A group of cases exists in which bone formation in the skin occurs without apparent cause. These can be grouped together under the descriptive term of osteosis cutis. They do not act as true neoplasms, some are hamartomas, the remainder are due to localized or diffuse metaplasia of connective tissue due to unknown stimuli.